[v2] mempool/ring: add support for new ring sync modes
diff mbox series

Message ID 20200629161024.29059-1-konstantin.ananyev@intel.com
State Superseded
Delegated to: David Marchand
Headers show
Series
  • [v2] mempool/ring: add support for new ring sync modes
Related show

Checks

Context Check Description
ci/Intel-compilation success Compilation OK
ci/iol-testing success Testing PASS
ci/iol-mellanox-Performance success Performance Testing PASS
ci/travis-robot success Travis build: passed
ci/iol-nxp-Performance success Performance Testing PASS
ci/iol-intel-Performance success Performance Testing PASS
ci/iol-broadcom-Performance success Performance Testing PASS
ci/checkpatch success coding style OK

Commit Message

Ananyev, Konstantin June 29, 2020, 4:10 p.m. UTC
v2:
 - update Release Notes (as per comments)

Two new sync modes were introduced into rte_ring:
relaxed tail sync (RTS) and head/tail sync (HTS).
This change provides user with ability to select these
modes for ring based mempool via mempool ops API.

Signed-off-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
Acked-by: Gage Eads <gage.eads@intel.com>
---
 doc/guides/rel_notes/release_20_08.rst  |  6 ++
 drivers/mempool/ring/rte_mempool_ring.c | 97 ++++++++++++++++++++++---
 2 files changed, 94 insertions(+), 9 deletions(-)

Comments

Olivier Matz July 9, 2020, 4:18 p.m. UTC | #1
Hi Konstantin,

On Mon, Jun 29, 2020 at 05:10:24PM +0100, Konstantin Ananyev wrote:
> v2:
>  - update Release Notes (as per comments)
> 
> Two new sync modes were introduced into rte_ring:
> relaxed tail sync (RTS) and head/tail sync (HTS).
> This change provides user with ability to select these
> modes for ring based mempool via mempool ops API.
> 
> Signed-off-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
> Acked-by: Gage Eads <gage.eads@intel.com>
> ---
>  doc/guides/rel_notes/release_20_08.rst  |  6 ++
>  drivers/mempool/ring/rte_mempool_ring.c | 97 ++++++++++++++++++++++---
>  2 files changed, 94 insertions(+), 9 deletions(-)
> 
> diff --git a/doc/guides/rel_notes/release_20_08.rst b/doc/guides/rel_notes/release_20_08.rst
> index eaaf11c37..7bdcf3aac 100644
> --- a/doc/guides/rel_notes/release_20_08.rst
> +++ b/doc/guides/rel_notes/release_20_08.rst
> @@ -84,6 +84,12 @@ New Features
>    * Dump ``rte_flow`` memory consumption.
>    * Measure packet per second forwarding.
>  
> +* **Added support for new sync modes into mempool ring driver.**
> +
> +  Added ability to select new ring synchronisation modes:
> +  ``relaxed tail sync (ring_mt_rts)`` and ``head/tail sync (ring_mt_hts)``
> +  via mempool ops API.
> +
>  
>  Removed Items
>  -------------
> diff --git a/drivers/mempool/ring/rte_mempool_ring.c b/drivers/mempool/ring/rte_mempool_ring.c
> index bc123fc52..15ec7dee7 100644
> --- a/drivers/mempool/ring/rte_mempool_ring.c
> +++ b/drivers/mempool/ring/rte_mempool_ring.c
> @@ -25,6 +25,22 @@ common_ring_sp_enqueue(struct rte_mempool *mp, void * const *obj_table,
>  			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
>  }
>  
> +static int
> +rts_ring_mp_enqueue(struct rte_mempool *mp, void * const *obj_table,
> +	unsigned int n)
> +{
> +	return rte_ring_mp_rts_enqueue_bulk(mp->pool_data,
> +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> +}
> +
> +static int
> +hts_ring_mp_enqueue(struct rte_mempool *mp, void * const *obj_table,
> +	unsigned int n)
> +{
> +	return rte_ring_mp_hts_enqueue_bulk(mp->pool_data,
> +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> +}
> +
>  static int
>  common_ring_mc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned n)
>  {
> @@ -39,17 +55,30 @@ common_ring_sc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned n)
>  			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
>  }
>  
> +static int
> +rts_ring_mc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned int n)
> +{
> +	return rte_ring_mc_rts_dequeue_bulk(mp->pool_data,
> +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> +}
> +
> +static int
> +hts_ring_mc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned int n)
> +{
> +	return rte_ring_mc_hts_dequeue_bulk(mp->pool_data,
> +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> +}
> +
>  static unsigned
>  common_ring_get_count(const struct rte_mempool *mp)
>  {
>  	return rte_ring_count(mp->pool_data);
>  }
>  
> -
>  static int
> -common_ring_alloc(struct rte_mempool *mp)
> +ring_alloc(struct rte_mempool *mp, uint32_t rg_flags)
>  {
> -	int rg_flags = 0, ret;
> +	int ret;
>  	char rg_name[RTE_RING_NAMESIZE];
>  	struct rte_ring *r;
>  
> @@ -60,12 +89,6 @@ common_ring_alloc(struct rte_mempool *mp)
>  		return -rte_errno;
>  	}
>  
> -	/* ring flags */
> -	if (mp->flags & MEMPOOL_F_SP_PUT)
> -		rg_flags |= RING_F_SP_ENQ;
> -	if (mp->flags & MEMPOOL_F_SC_GET)
> -		rg_flags |= RING_F_SC_DEQ;
> -
>  	/*
>  	 * Allocate the ring that will be used to store objects.
>  	 * Ring functions will return appropriate errors if we are
> @@ -82,6 +105,40 @@ common_ring_alloc(struct rte_mempool *mp)
>  	return 0;
>  }
>  
> +static int
> +common_ring_alloc(struct rte_mempool *mp)
> +{
> +	uint32_t rg_flags;
> +
> +	rg_flags = 0;

Maybe it could go on the same line

> +
> +	/* ring flags */

Not sure we need to keep this comment

> +	if (mp->flags & MEMPOOL_F_SP_PUT)
> +		rg_flags |= RING_F_SP_ENQ;
> +	if (mp->flags & MEMPOOL_F_SC_GET)
> +		rg_flags |= RING_F_SC_DEQ;
> +
> +	return ring_alloc(mp, rg_flags);
> +}
> +
> +static int
> +rts_ring_alloc(struct rte_mempool *mp)
> +{
> +	if ((mp->flags & (MEMPOOL_F_SP_PUT | MEMPOOL_F_SC_GET)) != 0)
> +		return -EINVAL;

Why do we need this? It is a problem to allow sc/sp in this mode (even
if it's not optimal)?

> +
> +	return ring_alloc(mp, RING_F_MP_RTS_ENQ | RING_F_MC_RTS_DEQ);
> +}
> +
> +static int
> +hts_ring_alloc(struct rte_mempool *mp)
> +{
> +	if ((mp->flags & (MEMPOOL_F_SP_PUT | MEMPOOL_F_SC_GET)) != 0)
> +		return -EINVAL;
> +
> +	return ring_alloc(mp, RING_F_MP_HTS_ENQ | RING_F_MC_HTS_DEQ);
> +}
> +
>  static void
>  common_ring_free(struct rte_mempool *mp)
>  {
> @@ -130,7 +187,29 @@ static const struct rte_mempool_ops ops_sp_mc = {
>  	.get_count = common_ring_get_count,
>  };
>  
> +/* ops for mempool with ring in MT_RTS sync mode */
> +static const struct rte_mempool_ops ops_mt_rts = {
> +	.name = "ring_mt_rts",
> +	.alloc = rts_ring_alloc,
> +	.free = common_ring_free,
> +	.enqueue = rts_ring_mp_enqueue,
> +	.dequeue = rts_ring_mc_dequeue,
> +	.get_count = common_ring_get_count,
> +};
> +
> +/* ops for mempool with ring in MT_HTS sync mode */
> +static const struct rte_mempool_ops ops_mt_hts = {
> +	.name = "ring_mt_hts",
> +	.alloc = hts_ring_alloc,
> +	.free = common_ring_free,
> +	.enqueue = hts_ring_mp_enqueue,
> +	.dequeue = hts_ring_mc_dequeue,
> +	.get_count = common_ring_get_count,
> +};
> +
>  MEMPOOL_REGISTER_OPS(ops_mp_mc);
>  MEMPOOL_REGISTER_OPS(ops_sp_sc);
>  MEMPOOL_REGISTER_OPS(ops_mp_sc);
>  MEMPOOL_REGISTER_OPS(ops_sp_mc);
> +MEMPOOL_REGISTER_OPS(ops_mt_rts);
> +MEMPOOL_REGISTER_OPS(ops_mt_hts);

Not really related to your patch, but I think we need a function to
dump the name of available mempool ops. We could even add a description.
The problem we have is that a user does not know on which criteria is
should use a driver or another (except for platform drivers).


Olivier
Ananyev, Konstantin July 9, 2020, 5:55 p.m. UTC | #2
Hi Olivier,
 
> Hi Konstantin,
> 
> On Mon, Jun 29, 2020 at 05:10:24PM +0100, Konstantin Ananyev wrote:
> > v2:
> >  - update Release Notes (as per comments)
> >
> > Two new sync modes were introduced into rte_ring:
> > relaxed tail sync (RTS) and head/tail sync (HTS).
> > This change provides user with ability to select these
> > modes for ring based mempool via mempool ops API.
> >
> > Signed-off-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
> > Acked-by: Gage Eads <gage.eads@intel.com>
> > ---
> >  doc/guides/rel_notes/release_20_08.rst  |  6 ++
> >  drivers/mempool/ring/rte_mempool_ring.c | 97 ++++++++++++++++++++++---
> >  2 files changed, 94 insertions(+), 9 deletions(-)
> >
> > diff --git a/doc/guides/rel_notes/release_20_08.rst b/doc/guides/rel_notes/release_20_08.rst
> > index eaaf11c37..7bdcf3aac 100644
> > --- a/doc/guides/rel_notes/release_20_08.rst
> > +++ b/doc/guides/rel_notes/release_20_08.rst
> > @@ -84,6 +84,12 @@ New Features
> >    * Dump ``rte_flow`` memory consumption.
> >    * Measure packet per second forwarding.
> >
> > +* **Added support for new sync modes into mempool ring driver.**
> > +
> > +  Added ability to select new ring synchronisation modes:
> > +  ``relaxed tail sync (ring_mt_rts)`` and ``head/tail sync (ring_mt_hts)``
> > +  via mempool ops API.
> > +
> >
> >  Removed Items
> >  -------------
> > diff --git a/drivers/mempool/ring/rte_mempool_ring.c b/drivers/mempool/ring/rte_mempool_ring.c
> > index bc123fc52..15ec7dee7 100644
> > --- a/drivers/mempool/ring/rte_mempool_ring.c
> > +++ b/drivers/mempool/ring/rte_mempool_ring.c
> > @@ -25,6 +25,22 @@ common_ring_sp_enqueue(struct rte_mempool *mp, void * const *obj_table,
> >  			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> >  }
> >
> > +static int
> > +rts_ring_mp_enqueue(struct rte_mempool *mp, void * const *obj_table,
> > +	unsigned int n)
> > +{
> > +	return rte_ring_mp_rts_enqueue_bulk(mp->pool_data,
> > +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > +}
> > +
> > +static int
> > +hts_ring_mp_enqueue(struct rte_mempool *mp, void * const *obj_table,
> > +	unsigned int n)
> > +{
> > +	return rte_ring_mp_hts_enqueue_bulk(mp->pool_data,
> > +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > +}
> > +
> >  static int
> >  common_ring_mc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned n)
> >  {
> > @@ -39,17 +55,30 @@ common_ring_sc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned n)
> >  			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> >  }
> >
> > +static int
> > +rts_ring_mc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned int n)
> > +{
> > +	return rte_ring_mc_rts_dequeue_bulk(mp->pool_data,
> > +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > +}
> > +
> > +static int
> > +hts_ring_mc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned int n)
> > +{
> > +	return rte_ring_mc_hts_dequeue_bulk(mp->pool_data,
> > +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > +}
> > +
> >  static unsigned
> >  common_ring_get_count(const struct rte_mempool *mp)
> >  {
> >  	return rte_ring_count(mp->pool_data);
> >  }
> >
> > -
> >  static int
> > -common_ring_alloc(struct rte_mempool *mp)
> > +ring_alloc(struct rte_mempool *mp, uint32_t rg_flags)
> >  {
> > -	int rg_flags = 0, ret;
> > +	int ret;
> >  	char rg_name[RTE_RING_NAMESIZE];
> >  	struct rte_ring *r;
> >
> > @@ -60,12 +89,6 @@ common_ring_alloc(struct rte_mempool *mp)
> >  		return -rte_errno;
> >  	}
> >
> > -	/* ring flags */
> > -	if (mp->flags & MEMPOOL_F_SP_PUT)
> > -		rg_flags |= RING_F_SP_ENQ;
> > -	if (mp->flags & MEMPOOL_F_SC_GET)
> > -		rg_flags |= RING_F_SC_DEQ;
> > -
> >  	/*
> >  	 * Allocate the ring that will be used to store objects.
> >  	 * Ring functions will return appropriate errors if we are
> > @@ -82,6 +105,40 @@ common_ring_alloc(struct rte_mempool *mp)
> >  	return 0;
> >  }
> >
> > +static int
> > +common_ring_alloc(struct rte_mempool *mp)
> > +{
> > +	uint32_t rg_flags;
> > +
> > +	rg_flags = 0;
> 
> Maybe it could go on the same line
> 
> > +
> > +	/* ring flags */
> 
> Not sure we need to keep this comment
> 
> > +	if (mp->flags & MEMPOOL_F_SP_PUT)
> > +		rg_flags |= RING_F_SP_ENQ;
> > +	if (mp->flags & MEMPOOL_F_SC_GET)
> > +		rg_flags |= RING_F_SC_DEQ;
> > +
> > +	return ring_alloc(mp, rg_flags);
> > +}
> > +
> > +static int
> > +rts_ring_alloc(struct rte_mempool *mp)
> > +{
> > +	if ((mp->flags & (MEMPOOL_F_SP_PUT | MEMPOOL_F_SC_GET)) != 0)
> > +		return -EINVAL;
> 
> Why do we need this? It is a problem to allow sc/sp in this mode (even
> if it's not optimal)?

These new sync modes (RTS, HTS) are for MT.
For SP/SC - there is simply no point to use MT sync modes.
I suppose there are few choices:
1. Make F_SP_PUT/F_SC_GET flags silently override expected ops behaviour
   and create actual ring with ST sync mode for prod/cons. 
2. Report an error.
3. Silently ignore these flags.

As I can see for  "ring_mp_mc" ops, we doing #1, 
while for "stack" we are doing #3.
For RTS/HTS I chosoe #2, as it seems cleaner to me.
Any thoughts from your side what preferable behaviour should be?

> 
> > +
> > +	return ring_alloc(mp, RING_F_MP_RTS_ENQ | RING_F_MC_RTS_DEQ);
> > +}
> > +
> > +static int
> > +hts_ring_alloc(struct rte_mempool *mp)
> > +{
> > +	if ((mp->flags & (MEMPOOL_F_SP_PUT | MEMPOOL_F_SC_GET)) != 0)
> > +		return -EINVAL;
> > +
> > +	return ring_alloc(mp, RING_F_MP_HTS_ENQ | RING_F_MC_HTS_DEQ);
> > +}
> > +
> >  static void
> >  common_ring_free(struct rte_mempool *mp)
> >  {
> > @@ -130,7 +187,29 @@ static const struct rte_mempool_ops ops_sp_mc = {
> >  	.get_count = common_ring_get_count,
> >  };
> >
> > +/* ops for mempool with ring in MT_RTS sync mode */
> > +static const struct rte_mempool_ops ops_mt_rts = {
> > +	.name = "ring_mt_rts",
> > +	.alloc = rts_ring_alloc,
> > +	.free = common_ring_free,
> > +	.enqueue = rts_ring_mp_enqueue,
> > +	.dequeue = rts_ring_mc_dequeue,
> > +	.get_count = common_ring_get_count,
> > +};
> > +
> > +/* ops for mempool with ring in MT_HTS sync mode */
> > +static const struct rte_mempool_ops ops_mt_hts = {
> > +	.name = "ring_mt_hts",
> > +	.alloc = hts_ring_alloc,
> > +	.free = common_ring_free,
> > +	.enqueue = hts_ring_mp_enqueue,
> > +	.dequeue = hts_ring_mc_dequeue,
> > +	.get_count = common_ring_get_count,
> > +};
> > +
> >  MEMPOOL_REGISTER_OPS(ops_mp_mc);
> >  MEMPOOL_REGISTER_OPS(ops_sp_sc);
> >  MEMPOOL_REGISTER_OPS(ops_mp_sc);
> >  MEMPOOL_REGISTER_OPS(ops_sp_mc);
> > +MEMPOOL_REGISTER_OPS(ops_mt_rts);
> > +MEMPOOL_REGISTER_OPS(ops_mt_hts);
 
> Not really related to your patch, but I think we need a function to
> dump the name of available mempool ops. We could even add a description.
> The problem we have is that a user does not know on which criteria is
> should use a driver or another (except for platform drivers).

Agree, it will be usefull.
Though it probably subject for a separate patch.
Olivier Matz July 10, 2020, 12:52 p.m. UTC | #3
Hi Konstantin,

On Thu, Jul 09, 2020 at 05:55:30PM +0000, Ananyev, Konstantin wrote:
> Hi Olivier,
>  
> > Hi Konstantin,
> > 
> > On Mon, Jun 29, 2020 at 05:10:24PM +0100, Konstantin Ananyev wrote:
> > > v2:
> > >  - update Release Notes (as per comments)
> > >
> > > Two new sync modes were introduced into rte_ring:
> > > relaxed tail sync (RTS) and head/tail sync (HTS).
> > > This change provides user with ability to select these
> > > modes for ring based mempool via mempool ops API.
> > >
> > > Signed-off-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
> > > Acked-by: Gage Eads <gage.eads@intel.com>
> > > ---
> > >  doc/guides/rel_notes/release_20_08.rst  |  6 ++
> > >  drivers/mempool/ring/rte_mempool_ring.c | 97 ++++++++++++++++++++++---
> > >  2 files changed, 94 insertions(+), 9 deletions(-)
> > >
> > > diff --git a/doc/guides/rel_notes/release_20_08.rst b/doc/guides/rel_notes/release_20_08.rst
> > > index eaaf11c37..7bdcf3aac 100644
> > > --- a/doc/guides/rel_notes/release_20_08.rst
> > > +++ b/doc/guides/rel_notes/release_20_08.rst
> > > @@ -84,6 +84,12 @@ New Features
> > >    * Dump ``rte_flow`` memory consumption.
> > >    * Measure packet per second forwarding.
> > >
> > > +* **Added support for new sync modes into mempool ring driver.**
> > > +
> > > +  Added ability to select new ring synchronisation modes:
> > > +  ``relaxed tail sync (ring_mt_rts)`` and ``head/tail sync (ring_mt_hts)``
> > > +  via mempool ops API.
> > > +
> > >
> > >  Removed Items
> > >  -------------
> > > diff --git a/drivers/mempool/ring/rte_mempool_ring.c b/drivers/mempool/ring/rte_mempool_ring.c
> > > index bc123fc52..15ec7dee7 100644
> > > --- a/drivers/mempool/ring/rte_mempool_ring.c
> > > +++ b/drivers/mempool/ring/rte_mempool_ring.c
> > > @@ -25,6 +25,22 @@ common_ring_sp_enqueue(struct rte_mempool *mp, void * const *obj_table,
> > >  			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > >  }
> > >
> > > +static int
> > > +rts_ring_mp_enqueue(struct rte_mempool *mp, void * const *obj_table,
> > > +	unsigned int n)
> > > +{
> > > +	return rte_ring_mp_rts_enqueue_bulk(mp->pool_data,
> > > +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > +}
> > > +
> > > +static int
> > > +hts_ring_mp_enqueue(struct rte_mempool *mp, void * const *obj_table,
> > > +	unsigned int n)
> > > +{
> > > +	return rte_ring_mp_hts_enqueue_bulk(mp->pool_data,
> > > +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > +}
> > > +
> > >  static int
> > >  common_ring_mc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned n)
> > >  {
> > > @@ -39,17 +55,30 @@ common_ring_sc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned n)
> > >  			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > >  }
> > >
> > > +static int
> > > +rts_ring_mc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned int n)
> > > +{
> > > +	return rte_ring_mc_rts_dequeue_bulk(mp->pool_data,
> > > +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > +}
> > > +
> > > +static int
> > > +hts_ring_mc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned int n)
> > > +{
> > > +	return rte_ring_mc_hts_dequeue_bulk(mp->pool_data,
> > > +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > +}
> > > +
> > >  static unsigned
> > >  common_ring_get_count(const struct rte_mempool *mp)
> > >  {
> > >  	return rte_ring_count(mp->pool_data);
> > >  }
> > >
> > > -
> > >  static int
> > > -common_ring_alloc(struct rte_mempool *mp)
> > > +ring_alloc(struct rte_mempool *mp, uint32_t rg_flags)
> > >  {
> > > -	int rg_flags = 0, ret;
> > > +	int ret;
> > >  	char rg_name[RTE_RING_NAMESIZE];
> > >  	struct rte_ring *r;
> > >
> > > @@ -60,12 +89,6 @@ common_ring_alloc(struct rte_mempool *mp)
> > >  		return -rte_errno;
> > >  	}
> > >
> > > -	/* ring flags */
> > > -	if (mp->flags & MEMPOOL_F_SP_PUT)
> > > -		rg_flags |= RING_F_SP_ENQ;
> > > -	if (mp->flags & MEMPOOL_F_SC_GET)
> > > -		rg_flags |= RING_F_SC_DEQ;
> > > -
> > >  	/*
> > >  	 * Allocate the ring that will be used to store objects.
> > >  	 * Ring functions will return appropriate errors if we are
> > > @@ -82,6 +105,40 @@ common_ring_alloc(struct rte_mempool *mp)
> > >  	return 0;
> > >  }
> > >
> > > +static int
> > > +common_ring_alloc(struct rte_mempool *mp)
> > > +{
> > > +	uint32_t rg_flags;
> > > +
> > > +	rg_flags = 0;
> > 
> > Maybe it could go on the same line
> > 
> > > +
> > > +	/* ring flags */
> > 
> > Not sure we need to keep this comment
> > 
> > > +	if (mp->flags & MEMPOOL_F_SP_PUT)
> > > +		rg_flags |= RING_F_SP_ENQ;
> > > +	if (mp->flags & MEMPOOL_F_SC_GET)
> > > +		rg_flags |= RING_F_SC_DEQ;
> > > +
> > > +	return ring_alloc(mp, rg_flags);
> > > +}
> > > +
> > > +static int
> > > +rts_ring_alloc(struct rte_mempool *mp)
> > > +{
> > > +	if ((mp->flags & (MEMPOOL_F_SP_PUT | MEMPOOL_F_SC_GET)) != 0)
> > > +		return -EINVAL;
> > 
> > Why do we need this? It is a problem to allow sc/sp in this mode (even
> > if it's not optimal)?
> 
> These new sync modes (RTS, HTS) are for MT.
> For SP/SC - there is simply no point to use MT sync modes.
> I suppose there are few choices:
> 1. Make F_SP_PUT/F_SC_GET flags silently override expected ops behaviour
>    and create actual ring with ST sync mode for prod/cons. 
> 2. Report an error.
> 3. Silently ignore these flags.
> 
> As I can see for  "ring_mp_mc" ops, we doing #1, 
> while for "stack" we are doing #3.
> For RTS/HTS I chosoe #2, as it seems cleaner to me.
> Any thoughts from your side what preferable behaviour should be?

The F_SP_PUT/F_SC_GET are only used in rte_mempool_create() to select
the default ops among (ring_sp_sc, ring_mp_sc, ring_sp_mc,
ring_mp_mc). I don't think we should look at it when using specific ops.

So I'll tend to say 3. is the correct thing to do.


> 
> > 
> > > +
> > > +	return ring_alloc(mp, RING_F_MP_RTS_ENQ | RING_F_MC_RTS_DEQ);
> > > +}
> > > +
> > > +static int
> > > +hts_ring_alloc(struct rte_mempool *mp)
> > > +{
> > > +	if ((mp->flags & (MEMPOOL_F_SP_PUT | MEMPOOL_F_SC_GET)) != 0)
> > > +		return -EINVAL;
> > > +
> > > +	return ring_alloc(mp, RING_F_MP_HTS_ENQ | RING_F_MC_HTS_DEQ);
> > > +}
> > > +
> > >  static void
> > >  common_ring_free(struct rte_mempool *mp)
> > >  {
> > > @@ -130,7 +187,29 @@ static const struct rte_mempool_ops ops_sp_mc = {
> > >  	.get_count = common_ring_get_count,
> > >  };
> > >
> > > +/* ops for mempool with ring in MT_RTS sync mode */
> > > +static const struct rte_mempool_ops ops_mt_rts = {
> > > +	.name = "ring_mt_rts",
> > > +	.alloc = rts_ring_alloc,
> > > +	.free = common_ring_free,
> > > +	.enqueue = rts_ring_mp_enqueue,
> > > +	.dequeue = rts_ring_mc_dequeue,
> > > +	.get_count = common_ring_get_count,
> > > +};
> > > +
> > > +/* ops for mempool with ring in MT_HTS sync mode */
> > > +static const struct rte_mempool_ops ops_mt_hts = {
> > > +	.name = "ring_mt_hts",
> > > +	.alloc = hts_ring_alloc,
> > > +	.free = common_ring_free,
> > > +	.enqueue = hts_ring_mp_enqueue,
> > > +	.dequeue = hts_ring_mc_dequeue,
> > > +	.get_count = common_ring_get_count,
> > > +};
> > > +
> > >  MEMPOOL_REGISTER_OPS(ops_mp_mc);
> > >  MEMPOOL_REGISTER_OPS(ops_sp_sc);
> > >  MEMPOOL_REGISTER_OPS(ops_mp_sc);
> > >  MEMPOOL_REGISTER_OPS(ops_sp_mc);
> > > +MEMPOOL_REGISTER_OPS(ops_mt_rts);
> > > +MEMPOOL_REGISTER_OPS(ops_mt_hts);
>  
> > Not really related to your patch, but I think we need a function to
> > dump the name of available mempool ops. We could even add a description.
> > The problem we have is that a user does not know on which criteria is
> > should use a driver or another (except for platform drivers).
> 
> Agree, it will be usefull.
> Though it probably subject for a separate patch.
>
Ananyev, Konstantin July 10, 2020, 3:15 p.m. UTC | #4
Hi Olivier,
 
> Hi Konstantin,
> 
> On Thu, Jul 09, 2020 at 05:55:30PM +0000, Ananyev, Konstantin wrote:
> > Hi Olivier,
> >
> > > Hi Konstantin,
> > >
> > > On Mon, Jun 29, 2020 at 05:10:24PM +0100, Konstantin Ananyev wrote:
> > > > v2:
> > > >  - update Release Notes (as per comments)
> > > >
> > > > Two new sync modes were introduced into rte_ring:
> > > > relaxed tail sync (RTS) and head/tail sync (HTS).
> > > > This change provides user with ability to select these
> > > > modes for ring based mempool via mempool ops API.
> > > >
> > > > Signed-off-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
> > > > Acked-by: Gage Eads <gage.eads@intel.com>
> > > > ---
> > > >  doc/guides/rel_notes/release_20_08.rst  |  6 ++
> > > >  drivers/mempool/ring/rte_mempool_ring.c | 97 ++++++++++++++++++++++---
> > > >  2 files changed, 94 insertions(+), 9 deletions(-)
> > > >
> > > > diff --git a/doc/guides/rel_notes/release_20_08.rst b/doc/guides/rel_notes/release_20_08.rst
> > > > index eaaf11c37..7bdcf3aac 100644
> > > > --- a/doc/guides/rel_notes/release_20_08.rst
> > > > +++ b/doc/guides/rel_notes/release_20_08.rst
> > > > @@ -84,6 +84,12 @@ New Features
> > > >    * Dump ``rte_flow`` memory consumption.
> > > >    * Measure packet per second forwarding.
> > > >
> > > > +* **Added support for new sync modes into mempool ring driver.**
> > > > +
> > > > +  Added ability to select new ring synchronisation modes:
> > > > +  ``relaxed tail sync (ring_mt_rts)`` and ``head/tail sync (ring_mt_hts)``
> > > > +  via mempool ops API.
> > > > +
> > > >
> > > >  Removed Items
> > > >  -------------
> > > > diff --git a/drivers/mempool/ring/rte_mempool_ring.c b/drivers/mempool/ring/rte_mempool_ring.c
> > > > index bc123fc52..15ec7dee7 100644
> > > > --- a/drivers/mempool/ring/rte_mempool_ring.c
> > > > +++ b/drivers/mempool/ring/rte_mempool_ring.c
> > > > @@ -25,6 +25,22 @@ common_ring_sp_enqueue(struct rte_mempool *mp, void * const *obj_table,
> > > >  			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > >  }
> > > >
> > > > +static int
> > > > +rts_ring_mp_enqueue(struct rte_mempool *mp, void * const *obj_table,
> > > > +	unsigned int n)
> > > > +{
> > > > +	return rte_ring_mp_rts_enqueue_bulk(mp->pool_data,
> > > > +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > +}
> > > > +
> > > > +static int
> > > > +hts_ring_mp_enqueue(struct rte_mempool *mp, void * const *obj_table,
> > > > +	unsigned int n)
> > > > +{
> > > > +	return rte_ring_mp_hts_enqueue_bulk(mp->pool_data,
> > > > +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > +}
> > > > +
> > > >  static int
> > > >  common_ring_mc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned n)
> > > >  {
> > > > @@ -39,17 +55,30 @@ common_ring_sc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned n)
> > > >  			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > >  }
> > > >
> > > > +static int
> > > > +rts_ring_mc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned int n)
> > > > +{
> > > > +	return rte_ring_mc_rts_dequeue_bulk(mp->pool_data,
> > > > +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > +}
> > > > +
> > > > +static int
> > > > +hts_ring_mc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned int n)
> > > > +{
> > > > +	return rte_ring_mc_hts_dequeue_bulk(mp->pool_data,
> > > > +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > +}
> > > > +
> > > >  static unsigned
> > > >  common_ring_get_count(const struct rte_mempool *mp)
> > > >  {
> > > >  	return rte_ring_count(mp->pool_data);
> > > >  }
> > > >
> > > > -
> > > >  static int
> > > > -common_ring_alloc(struct rte_mempool *mp)
> > > > +ring_alloc(struct rte_mempool *mp, uint32_t rg_flags)
> > > >  {
> > > > -	int rg_flags = 0, ret;
> > > > +	int ret;
> > > >  	char rg_name[RTE_RING_NAMESIZE];
> > > >  	struct rte_ring *r;
> > > >
> > > > @@ -60,12 +89,6 @@ common_ring_alloc(struct rte_mempool *mp)
> > > >  		return -rte_errno;
> > > >  	}
> > > >
> > > > -	/* ring flags */
> > > > -	if (mp->flags & MEMPOOL_F_SP_PUT)
> > > > -		rg_flags |= RING_F_SP_ENQ;
> > > > -	if (mp->flags & MEMPOOL_F_SC_GET)
> > > > -		rg_flags |= RING_F_SC_DEQ;
> > > > -
> > > >  	/*
> > > >  	 * Allocate the ring that will be used to store objects.
> > > >  	 * Ring functions will return appropriate errors if we are
> > > > @@ -82,6 +105,40 @@ common_ring_alloc(struct rte_mempool *mp)
> > > >  	return 0;
> > > >  }
> > > >
> > > > +static int
> > > > +common_ring_alloc(struct rte_mempool *mp)
> > > > +{
> > > > +	uint32_t rg_flags;
> > > > +
> > > > +	rg_flags = 0;
> > >
> > > Maybe it could go on the same line
> > >
> > > > +
> > > > +	/* ring flags */
> > >
> > > Not sure we need to keep this comment
> > >
> > > > +	if (mp->flags & MEMPOOL_F_SP_PUT)
> > > > +		rg_flags |= RING_F_SP_ENQ;
> > > > +	if (mp->flags & MEMPOOL_F_SC_GET)
> > > > +		rg_flags |= RING_F_SC_DEQ;
> > > > +
> > > > +	return ring_alloc(mp, rg_flags);
> > > > +}
> > > > +
> > > > +static int
> > > > +rts_ring_alloc(struct rte_mempool *mp)
> > > > +{
> > > > +	if ((mp->flags & (MEMPOOL_F_SP_PUT | MEMPOOL_F_SC_GET)) != 0)
> > > > +		return -EINVAL;
> > >
> > > Why do we need this? It is a problem to allow sc/sp in this mode (even
> > > if it's not optimal)?
> >
> > These new sync modes (RTS, HTS) are for MT.
> > For SP/SC - there is simply no point to use MT sync modes.
> > I suppose there are few choices:
> > 1. Make F_SP_PUT/F_SC_GET flags silently override expected ops behaviour
> >    and create actual ring with ST sync mode for prod/cons.
> > 2. Report an error.
> > 3. Silently ignore these flags.
> >
> > As I can see for  "ring_mp_mc" ops, we doing #1,
> > while for "stack" we are doing #3.
> > For RTS/HTS I chosoe #2, as it seems cleaner to me.
> > Any thoughts from your side what preferable behaviour should be?
> 
> The F_SP_PUT/F_SC_GET are only used in rte_mempool_create() to select
> the default ops among (ring_sp_sc, ring_mp_sc, ring_sp_mc,
> ring_mp_mc). 

As I understand, nothing prevents user from doing:

mp = rte_mempool_create_empty(name, n, elt_size, cache_size,
                 sizeof(struct rte_pktmbuf_pool_private), socket_id, 0);


>I don't think we should look at it when using specific ops.
> 
> So I'll tend to say 3. is the correct thing to do.

Ok, will resend v3 then.

> 
> >
> > >
> > > > +
> > > > +	return ring_alloc(mp, RING_F_MP_RTS_ENQ | RING_F_MC_RTS_DEQ);
> > > > +}
> > > > +
> > > > +static int
> > > > +hts_ring_alloc(struct rte_mempool *mp)
> > > > +{
> > > > +	if ((mp->flags & (MEMPOOL_F_SP_PUT | MEMPOOL_F_SC_GET)) != 0)
> > > > +		return -EINVAL;
> > > > +
> > > > +	return ring_alloc(mp, RING_F_MP_HTS_ENQ | RING_F_MC_HTS_DEQ);
> > > > +}
> > > > +
> > > >  static void
> > > >  common_ring_free(struct rte_mempool *mp)
> > > >  {
> > > > @@ -130,7 +187,29 @@ static const struct rte_mempool_ops ops_sp_mc = {
> > > >  	.get_count = common_ring_get_count,
> > > >  };
> > > >
> > > > +/* ops for mempool with ring in MT_RTS sync mode */
> > > > +static const struct rte_mempool_ops ops_mt_rts = {
> > > > +	.name = "ring_mt_rts",
> > > > +	.alloc = rts_ring_alloc,
> > > > +	.free = common_ring_free,
> > > > +	.enqueue = rts_ring_mp_enqueue,
> > > > +	.dequeue = rts_ring_mc_dequeue,
> > > > +	.get_count = common_ring_get_count,
> > > > +};
> > > > +
> > > > +/* ops for mempool with ring in MT_HTS sync mode */
> > > > +static const struct rte_mempool_ops ops_mt_hts = {
> > > > +	.name = "ring_mt_hts",
> > > > +	.alloc = hts_ring_alloc,
> > > > +	.free = common_ring_free,
> > > > +	.enqueue = hts_ring_mp_enqueue,
> > > > +	.dequeue = hts_ring_mc_dequeue,
> > > > +	.get_count = common_ring_get_count,
> > > > +};
> > > > +
> > > >  MEMPOOL_REGISTER_OPS(ops_mp_mc);
> > > >  MEMPOOL_REGISTER_OPS(ops_sp_sc);
> > > >  MEMPOOL_REGISTER_OPS(ops_mp_sc);
> > > >  MEMPOOL_REGISTER_OPS(ops_sp_mc);
> > > > +MEMPOOL_REGISTER_OPS(ops_mt_rts);
> > > > +MEMPOOL_REGISTER_OPS(ops_mt_hts);
> >
> > > Not really related to your patch, but I think we need a function to
> > > dump the name of available mempool ops. We could even add a description.
> > > The problem we have is that a user does not know on which criteria is
> > > should use a driver or another (except for platform drivers).
> >
> > Agree, it will be usefull.
> > Though it probably subject for a separate patch.
> >
Ananyev, Konstantin July 10, 2020, 3:20 p.m. UTC | #5
> 
> Hi Olivier,
> 
> > Hi Konstantin,
> >
> > On Thu, Jul 09, 2020 at 05:55:30PM +0000, Ananyev, Konstantin wrote:
> > > Hi Olivier,
> > >
> > > > Hi Konstantin,
> > > >
> > > > On Mon, Jun 29, 2020 at 05:10:24PM +0100, Konstantin Ananyev wrote:
> > > > > v2:
> > > > >  - update Release Notes (as per comments)
> > > > >
> > > > > Two new sync modes were introduced into rte_ring:
> > > > > relaxed tail sync (RTS) and head/tail sync (HTS).
> > > > > This change provides user with ability to select these
> > > > > modes for ring based mempool via mempool ops API.
> > > > >
> > > > > Signed-off-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
> > > > > Acked-by: Gage Eads <gage.eads@intel.com>
> > > > > ---
> > > > >  doc/guides/rel_notes/release_20_08.rst  |  6 ++
> > > > >  drivers/mempool/ring/rte_mempool_ring.c | 97 ++++++++++++++++++++++---
> > > > >  2 files changed, 94 insertions(+), 9 deletions(-)
> > > > >
> > > > > diff --git a/doc/guides/rel_notes/release_20_08.rst b/doc/guides/rel_notes/release_20_08.rst
> > > > > index eaaf11c37..7bdcf3aac 100644
> > > > > --- a/doc/guides/rel_notes/release_20_08.rst
> > > > > +++ b/doc/guides/rel_notes/release_20_08.rst
> > > > > @@ -84,6 +84,12 @@ New Features
> > > > >    * Dump ``rte_flow`` memory consumption.
> > > > >    * Measure packet per second forwarding.
> > > > >
> > > > > +* **Added support for new sync modes into mempool ring driver.**
> > > > > +
> > > > > +  Added ability to select new ring synchronisation modes:
> > > > > +  ``relaxed tail sync (ring_mt_rts)`` and ``head/tail sync (ring_mt_hts)``
> > > > > +  via mempool ops API.
> > > > > +
> > > > >
> > > > >  Removed Items
> > > > >  -------------
> > > > > diff --git a/drivers/mempool/ring/rte_mempool_ring.c b/drivers/mempool/ring/rte_mempool_ring.c
> > > > > index bc123fc52..15ec7dee7 100644
> > > > > --- a/drivers/mempool/ring/rte_mempool_ring.c
> > > > > +++ b/drivers/mempool/ring/rte_mempool_ring.c
> > > > > @@ -25,6 +25,22 @@ common_ring_sp_enqueue(struct rte_mempool *mp, void * const *obj_table,
> > > > >  			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > >  }
> > > > >
> > > > > +static int
> > > > > +rts_ring_mp_enqueue(struct rte_mempool *mp, void * const *obj_table,
> > > > > +	unsigned int n)
> > > > > +{
> > > > > +	return rte_ring_mp_rts_enqueue_bulk(mp->pool_data,
> > > > > +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > > +}
> > > > > +
> > > > > +static int
> > > > > +hts_ring_mp_enqueue(struct rte_mempool *mp, void * const *obj_table,
> > > > > +	unsigned int n)
> > > > > +{
> > > > > +	return rte_ring_mp_hts_enqueue_bulk(mp->pool_data,
> > > > > +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > > +}
> > > > > +
> > > > >  static int
> > > > >  common_ring_mc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned n)
> > > > >  {
> > > > > @@ -39,17 +55,30 @@ common_ring_sc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned n)
> > > > >  			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > >  }
> > > > >
> > > > > +static int
> > > > > +rts_ring_mc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned int n)
> > > > > +{
> > > > > +	return rte_ring_mc_rts_dequeue_bulk(mp->pool_data,
> > > > > +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > > +}
> > > > > +
> > > > > +static int
> > > > > +hts_ring_mc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned int n)
> > > > > +{
> > > > > +	return rte_ring_mc_hts_dequeue_bulk(mp->pool_data,
> > > > > +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > > +}
> > > > > +
> > > > >  static unsigned
> > > > >  common_ring_get_count(const struct rte_mempool *mp)
> > > > >  {
> > > > >  	return rte_ring_count(mp->pool_data);
> > > > >  }
> > > > >
> > > > > -
> > > > >  static int
> > > > > -common_ring_alloc(struct rte_mempool *mp)
> > > > > +ring_alloc(struct rte_mempool *mp, uint32_t rg_flags)
> > > > >  {
> > > > > -	int rg_flags = 0, ret;
> > > > > +	int ret;
> > > > >  	char rg_name[RTE_RING_NAMESIZE];
> > > > >  	struct rte_ring *r;
> > > > >
> > > > > @@ -60,12 +89,6 @@ common_ring_alloc(struct rte_mempool *mp)
> > > > >  		return -rte_errno;
> > > > >  	}
> > > > >
> > > > > -	/* ring flags */
> > > > > -	if (mp->flags & MEMPOOL_F_SP_PUT)
> > > > > -		rg_flags |= RING_F_SP_ENQ;
> > > > > -	if (mp->flags & MEMPOOL_F_SC_GET)
> > > > > -		rg_flags |= RING_F_SC_DEQ;
> > > > > -
> > > > >  	/*
> > > > >  	 * Allocate the ring that will be used to store objects.
> > > > >  	 * Ring functions will return appropriate errors if we are
> > > > > @@ -82,6 +105,40 @@ common_ring_alloc(struct rte_mempool *mp)
> > > > >  	return 0;
> > > > >  }
> > > > >
> > > > > +static int
> > > > > +common_ring_alloc(struct rte_mempool *mp)
> > > > > +{
> > > > > +	uint32_t rg_flags;
> > > > > +
> > > > > +	rg_flags = 0;
> > > >
> > > > Maybe it could go on the same line
> > > >
> > > > > +
> > > > > +	/* ring flags */
> > > >
> > > > Not sure we need to keep this comment
> > > >
> > > > > +	if (mp->flags & MEMPOOL_F_SP_PUT)
> > > > > +		rg_flags |= RING_F_SP_ENQ;
> > > > > +	if (mp->flags & MEMPOOL_F_SC_GET)
> > > > > +		rg_flags |= RING_F_SC_DEQ;
> > > > > +
> > > > > +	return ring_alloc(mp, rg_flags);
> > > > > +}
> > > > > +
> > > > > +static int
> > > > > +rts_ring_alloc(struct rte_mempool *mp)
> > > > > +{
> > > > > +	if ((mp->flags & (MEMPOOL_F_SP_PUT | MEMPOOL_F_SC_GET)) != 0)
> > > > > +		return -EINVAL;
> > > >
> > > > Why do we need this? It is a problem to allow sc/sp in this mode (even
> > > > if it's not optimal)?
> > >
> > > These new sync modes (RTS, HTS) are for MT.
> > > For SP/SC - there is simply no point to use MT sync modes.
> > > I suppose there are few choices:
> > > 1. Make F_SP_PUT/F_SC_GET flags silently override expected ops behaviour
> > >    and create actual ring with ST sync mode for prod/cons.
> > > 2. Report an error.
> > > 3. Silently ignore these flags.
> > >
> > > As I can see for  "ring_mp_mc" ops, we doing #1,
> > > while for "stack" we are doing #3.
> > > For RTS/HTS I chosoe #2, as it seems cleaner to me.
> > > Any thoughts from your side what preferable behaviour should be?
> >
> > The F_SP_PUT/F_SC_GET are only used in rte_mempool_create() to select
> > the default ops among (ring_sp_sc, ring_mp_sc, ring_sp_mc,
> > ring_mp_mc).
> 
> As I understand, nothing prevents user from doing:
> 
> mp = rte_mempool_create_empty(name, n, elt_size, cache_size,
>                  sizeof(struct rte_pktmbuf_pool_private), socket_id, 0);

Apologies, hit send accidently.
I meant user can do:

mp = rte_mempool_create_empty(..., F_SP_PUT | F_SC_GET);
rte_mempool_set_ops_byname(mp, "ring_mp_mc", NULL);

An in that case, he'll get SP/SC ring underneath.

> 
> 
> >I don't think we should look at it when using specific ops.
> >
> > So I'll tend to say 3. is the correct thing to do.
> 
> Ok, will resend v3 then.
>
Olivier Matz July 13, 2020, 1:30 p.m. UTC | #6
Hi Konstantin,

On Fri, Jul 10, 2020 at 03:20:12PM +0000, Ananyev, Konstantin wrote:
> 
> 
> > 
> > Hi Olivier,
> > 
> > > Hi Konstantin,
> > >
> > > On Thu, Jul 09, 2020 at 05:55:30PM +0000, Ananyev, Konstantin wrote:
> > > > Hi Olivier,
> > > >
> > > > > Hi Konstantin,
> > > > >
> > > > > On Mon, Jun 29, 2020 at 05:10:24PM +0100, Konstantin Ananyev wrote:
> > > > > > v2:
> > > > > >  - update Release Notes (as per comments)
> > > > > >
> > > > > > Two new sync modes were introduced into rte_ring:
> > > > > > relaxed tail sync (RTS) and head/tail sync (HTS).
> > > > > > This change provides user with ability to select these
> > > > > > modes for ring based mempool via mempool ops API.
> > > > > >
> > > > > > Signed-off-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
> > > > > > Acked-by: Gage Eads <gage.eads@intel.com>
> > > > > > ---
> > > > > >  doc/guides/rel_notes/release_20_08.rst  |  6 ++
> > > > > >  drivers/mempool/ring/rte_mempool_ring.c | 97 ++++++++++++++++++++++---
> > > > > >  2 files changed, 94 insertions(+), 9 deletions(-)
> > > > > >
> > > > > > diff --git a/doc/guides/rel_notes/release_20_08.rst b/doc/guides/rel_notes/release_20_08.rst
> > > > > > index eaaf11c37..7bdcf3aac 100644
> > > > > > --- a/doc/guides/rel_notes/release_20_08.rst
> > > > > > +++ b/doc/guides/rel_notes/release_20_08.rst
> > > > > > @@ -84,6 +84,12 @@ New Features
> > > > > >    * Dump ``rte_flow`` memory consumption.
> > > > > >    * Measure packet per second forwarding.
> > > > > >
> > > > > > +* **Added support for new sync modes into mempool ring driver.**
> > > > > > +
> > > > > > +  Added ability to select new ring synchronisation modes:
> > > > > > +  ``relaxed tail sync (ring_mt_rts)`` and ``head/tail sync (ring_mt_hts)``
> > > > > > +  via mempool ops API.
> > > > > > +
> > > > > >
> > > > > >  Removed Items
> > > > > >  -------------
> > > > > > diff --git a/drivers/mempool/ring/rte_mempool_ring.c b/drivers/mempool/ring/rte_mempool_ring.c
> > > > > > index bc123fc52..15ec7dee7 100644
> > > > > > --- a/drivers/mempool/ring/rte_mempool_ring.c
> > > > > > +++ b/drivers/mempool/ring/rte_mempool_ring.c
> > > > > > @@ -25,6 +25,22 @@ common_ring_sp_enqueue(struct rte_mempool *mp, void * const *obj_table,
> > > > > >  			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > > >  }
> > > > > >
> > > > > > +static int
> > > > > > +rts_ring_mp_enqueue(struct rte_mempool *mp, void * const *obj_table,
> > > > > > +	unsigned int n)
> > > > > > +{
> > > > > > +	return rte_ring_mp_rts_enqueue_bulk(mp->pool_data,
> > > > > > +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > > > +}
> > > > > > +
> > > > > > +static int
> > > > > > +hts_ring_mp_enqueue(struct rte_mempool *mp, void * const *obj_table,
> > > > > > +	unsigned int n)
> > > > > > +{
> > > > > > +	return rte_ring_mp_hts_enqueue_bulk(mp->pool_data,
> > > > > > +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > > > +}
> > > > > > +
> > > > > >  static int
> > > > > >  common_ring_mc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned n)
> > > > > >  {
> > > > > > @@ -39,17 +55,30 @@ common_ring_sc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned n)
> > > > > >  			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > > >  }
> > > > > >
> > > > > > +static int
> > > > > > +rts_ring_mc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned int n)
> > > > > > +{
> > > > > > +	return rte_ring_mc_rts_dequeue_bulk(mp->pool_data,
> > > > > > +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > > > +}
> > > > > > +
> > > > > > +static int
> > > > > > +hts_ring_mc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned int n)
> > > > > > +{
> > > > > > +	return rte_ring_mc_hts_dequeue_bulk(mp->pool_data,
> > > > > > +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > > > +}
> > > > > > +
> > > > > >  static unsigned
> > > > > >  common_ring_get_count(const struct rte_mempool *mp)
> > > > > >  {
> > > > > >  	return rte_ring_count(mp->pool_data);
> > > > > >  }
> > > > > >
> > > > > > -
> > > > > >  static int
> > > > > > -common_ring_alloc(struct rte_mempool *mp)
> > > > > > +ring_alloc(struct rte_mempool *mp, uint32_t rg_flags)
> > > > > >  {
> > > > > > -	int rg_flags = 0, ret;
> > > > > > +	int ret;
> > > > > >  	char rg_name[RTE_RING_NAMESIZE];
> > > > > >  	struct rte_ring *r;
> > > > > >
> > > > > > @@ -60,12 +89,6 @@ common_ring_alloc(struct rte_mempool *mp)
> > > > > >  		return -rte_errno;
> > > > > >  	}
> > > > > >
> > > > > > -	/* ring flags */
> > > > > > -	if (mp->flags & MEMPOOL_F_SP_PUT)
> > > > > > -		rg_flags |= RING_F_SP_ENQ;
> > > > > > -	if (mp->flags & MEMPOOL_F_SC_GET)
> > > > > > -		rg_flags |= RING_F_SC_DEQ;
> > > > > > -
> > > > > >  	/*
> > > > > >  	 * Allocate the ring that will be used to store objects.
> > > > > >  	 * Ring functions will return appropriate errors if we are
> > > > > > @@ -82,6 +105,40 @@ common_ring_alloc(struct rte_mempool *mp)
> > > > > >  	return 0;
> > > > > >  }
> > > > > >
> > > > > > +static int
> > > > > > +common_ring_alloc(struct rte_mempool *mp)
> > > > > > +{
> > > > > > +	uint32_t rg_flags;
> > > > > > +
> > > > > > +	rg_flags = 0;
> > > > >
> > > > > Maybe it could go on the same line
> > > > >
> > > > > > +
> > > > > > +	/* ring flags */
> > > > >
> > > > > Not sure we need to keep this comment
> > > > >
> > > > > > +	if (mp->flags & MEMPOOL_F_SP_PUT)
> > > > > > +		rg_flags |= RING_F_SP_ENQ;
> > > > > > +	if (mp->flags & MEMPOOL_F_SC_GET)
> > > > > > +		rg_flags |= RING_F_SC_DEQ;
> > > > > > +
> > > > > > +	return ring_alloc(mp, rg_flags);
> > > > > > +}
> > > > > > +
> > > > > > +static int
> > > > > > +rts_ring_alloc(struct rte_mempool *mp)
> > > > > > +{
> > > > > > +	if ((mp->flags & (MEMPOOL_F_SP_PUT | MEMPOOL_F_SC_GET)) != 0)
> > > > > > +		return -EINVAL;
> > > > >
> > > > > Why do we need this? It is a problem to allow sc/sp in this mode (even
> > > > > if it's not optimal)?
> > > >
> > > > These new sync modes (RTS, HTS) are for MT.
> > > > For SP/SC - there is simply no point to use MT sync modes.
> > > > I suppose there are few choices:
> > > > 1. Make F_SP_PUT/F_SC_GET flags silently override expected ops behaviour
> > > >    and create actual ring with ST sync mode for prod/cons.
> > > > 2. Report an error.
> > > > 3. Silently ignore these flags.
> > > >
> > > > As I can see for  "ring_mp_mc" ops, we doing #1,
> > > > while for "stack" we are doing #3.
> > > > For RTS/HTS I chosoe #2, as it seems cleaner to me.
> > > > Any thoughts from your side what preferable behaviour should be?
> > >
> > > The F_SP_PUT/F_SC_GET are only used in rte_mempool_create() to select
> > > the default ops among (ring_sp_sc, ring_mp_sc, ring_sp_mc,
> > > ring_mp_mc).
> > 
> > As I understand, nothing prevents user from doing:
> > 
> > mp = rte_mempool_create_empty(name, n, elt_size, cache_size,
> >                  sizeof(struct rte_pktmbuf_pool_private), socket_id, 0);
> 
> Apologies, hit send accidently.
> I meant user can do:
> 
> mp = rte_mempool_create_empty(..., F_SP_PUT | F_SC_GET);
> rte_mempool_set_ops_byname(mp, "ring_mp_mc", NULL);
> 
> An in that case, he'll get SP/SC ring underneath.

It looks it's not the case. Since commit 449c49b93a6b ("mempool: support
handler operations"), the flags SP_PUT/SC_GET are converted into a call
to rte_mempool_set_ops_byname() in rte_mempool_create() only.

In rte_mempool_create_empty(), these flags are ignored. It is expected
that the user calls rte_mempool_set_ops_byname() by itself.

I don't think it is a good behavior:

1/ The documentation of rte_mempool_create_empty() does not say that the
   flags are ignored, and a user can expect that F_SP_PUT | F_SC_GET
   sets the default ops like rte_mempool_create().

2/ If rte_mempool_set_ops_byname() is not called after
   rte_mempool_create_empty() (and it looks it happens in dpdk's code),
   the default ops are the ones registered at index 0. This depends on
   the link order.

So I propose to move the following code in
rte_mempool_create_empty().

	if ((flags & MEMPOOL_F_SP_PUT) && (flags & MEMPOOL_F_SC_GET))
		ret = rte_mempool_set_ops_byname(mp, "ring_sp_sc", NULL);
	else if (flags & MEMPOOL_F_SP_PUT)
		ret = rte_mempool_set_ops_byname(mp, "ring_sp_mc", NULL);
	else if (flags & MEMPOOL_F_SC_GET)
		ret = rte_mempool_set_ops_byname(mp, "ring_mp_sc", NULL);
	else
		ret = rte_mempool_set_ops_byname(mp, "ring_mp_mc", NULL);

What do you think?



> 
> > 
> > 
> > >I don't think we should look at it when using specific ops.
> > >
> > > So I'll tend to say 3. is the correct thing to do.
> > 
> > Ok, will resend v3 then.
> >
Ananyev, Konstantin July 13, 2020, 2:46 p.m. UTC | #7
Hi Olivier,

> Hi Konstantin,
> 
> On Fri, Jul 10, 2020 at 03:20:12PM +0000, Ananyev, Konstantin wrote:
> >
> >
> > >
> > > Hi Olivier,
> > >
> > > > Hi Konstantin,
> > > >
> > > > On Thu, Jul 09, 2020 at 05:55:30PM +0000, Ananyev, Konstantin wrote:
> > > > > Hi Olivier,
> > > > >
> > > > > > Hi Konstantin,
> > > > > >
> > > > > > On Mon, Jun 29, 2020 at 05:10:24PM +0100, Konstantin Ananyev wrote:
> > > > > > > v2:
> > > > > > >  - update Release Notes (as per comments)
> > > > > > >
> > > > > > > Two new sync modes were introduced into rte_ring:
> > > > > > > relaxed tail sync (RTS) and head/tail sync (HTS).
> > > > > > > This change provides user with ability to select these
> > > > > > > modes for ring based mempool via mempool ops API.
> > > > > > >
> > > > > > > Signed-off-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
> > > > > > > Acked-by: Gage Eads <gage.eads@intel.com>
> > > > > > > ---
> > > > > > >  doc/guides/rel_notes/release_20_08.rst  |  6 ++
> > > > > > >  drivers/mempool/ring/rte_mempool_ring.c | 97 ++++++++++++++++++++++---
> > > > > > >  2 files changed, 94 insertions(+), 9 deletions(-)
> > > > > > >
> > > > > > > diff --git a/doc/guides/rel_notes/release_20_08.rst b/doc/guides/rel_notes/release_20_08.rst
> > > > > > > index eaaf11c37..7bdcf3aac 100644
> > > > > > > --- a/doc/guides/rel_notes/release_20_08.rst
> > > > > > > +++ b/doc/guides/rel_notes/release_20_08.rst
> > > > > > > @@ -84,6 +84,12 @@ New Features
> > > > > > >    * Dump ``rte_flow`` memory consumption.
> > > > > > >    * Measure packet per second forwarding.
> > > > > > >
> > > > > > > +* **Added support for new sync modes into mempool ring driver.**
> > > > > > > +
> > > > > > > +  Added ability to select new ring synchronisation modes:
> > > > > > > +  ``relaxed tail sync (ring_mt_rts)`` and ``head/tail sync (ring_mt_hts)``
> > > > > > > +  via mempool ops API.
> > > > > > > +
> > > > > > >
> > > > > > >  Removed Items
> > > > > > >  -------------
> > > > > > > diff --git a/drivers/mempool/ring/rte_mempool_ring.c b/drivers/mempool/ring/rte_mempool_ring.c
> > > > > > > index bc123fc52..15ec7dee7 100644
> > > > > > > --- a/drivers/mempool/ring/rte_mempool_ring.c
> > > > > > > +++ b/drivers/mempool/ring/rte_mempool_ring.c
> > > > > > > @@ -25,6 +25,22 @@ common_ring_sp_enqueue(struct rte_mempool *mp, void * const *obj_table,
> > > > > > >  			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > > > >  }
> > > > > > >
> > > > > > > +static int
> > > > > > > +rts_ring_mp_enqueue(struct rte_mempool *mp, void * const *obj_table,
> > > > > > > +	unsigned int n)
> > > > > > > +{
> > > > > > > +	return rte_ring_mp_rts_enqueue_bulk(mp->pool_data,
> > > > > > > +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > > > > +}
> > > > > > > +
> > > > > > > +static int
> > > > > > > +hts_ring_mp_enqueue(struct rte_mempool *mp, void * const *obj_table,
> > > > > > > +	unsigned int n)
> > > > > > > +{
> > > > > > > +	return rte_ring_mp_hts_enqueue_bulk(mp->pool_data,
> > > > > > > +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > > > > +}
> > > > > > > +
> > > > > > >  static int
> > > > > > >  common_ring_mc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned n)
> > > > > > >  {
> > > > > > > @@ -39,17 +55,30 @@ common_ring_sc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned n)
> > > > > > >  			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > > > >  }
> > > > > > >
> > > > > > > +static int
> > > > > > > +rts_ring_mc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned int n)
> > > > > > > +{
> > > > > > > +	return rte_ring_mc_rts_dequeue_bulk(mp->pool_data,
> > > > > > > +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > > > > +}
> > > > > > > +
> > > > > > > +static int
> > > > > > > +hts_ring_mc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned int n)
> > > > > > > +{
> > > > > > > +	return rte_ring_mc_hts_dequeue_bulk(mp->pool_data,
> > > > > > > +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > > > > +}
> > > > > > > +
> > > > > > >  static unsigned
> > > > > > >  common_ring_get_count(const struct rte_mempool *mp)
> > > > > > >  {
> > > > > > >  	return rte_ring_count(mp->pool_data);
> > > > > > >  }
> > > > > > >
> > > > > > > -
> > > > > > >  static int
> > > > > > > -common_ring_alloc(struct rte_mempool *mp)
> > > > > > > +ring_alloc(struct rte_mempool *mp, uint32_t rg_flags)
> > > > > > >  {
> > > > > > > -	int rg_flags = 0, ret;
> > > > > > > +	int ret;
> > > > > > >  	char rg_name[RTE_RING_NAMESIZE];
> > > > > > >  	struct rte_ring *r;
> > > > > > >
> > > > > > > @@ -60,12 +89,6 @@ common_ring_alloc(struct rte_mempool *mp)
> > > > > > >  		return -rte_errno;
> > > > > > >  	}
> > > > > > >
> > > > > > > -	/* ring flags */
> > > > > > > -	if (mp->flags & MEMPOOL_F_SP_PUT)
> > > > > > > -		rg_flags |= RING_F_SP_ENQ;
> > > > > > > -	if (mp->flags & MEMPOOL_F_SC_GET)
> > > > > > > -		rg_flags |= RING_F_SC_DEQ;
> > > > > > > -
> > > > > > >  	/*
> > > > > > >  	 * Allocate the ring that will be used to store objects.
> > > > > > >  	 * Ring functions will return appropriate errors if we are
> > > > > > > @@ -82,6 +105,40 @@ common_ring_alloc(struct rte_mempool *mp)
> > > > > > >  	return 0;
> > > > > > >  }
> > > > > > >
> > > > > > > +static int
> > > > > > > +common_ring_alloc(struct rte_mempool *mp)
> > > > > > > +{
> > > > > > > +	uint32_t rg_flags;
> > > > > > > +
> > > > > > > +	rg_flags = 0;
> > > > > >
> > > > > > Maybe it could go on the same line
> > > > > >
> > > > > > > +
> > > > > > > +	/* ring flags */
> > > > > >
> > > > > > Not sure we need to keep this comment
> > > > > >
> > > > > > > +	if (mp->flags & MEMPOOL_F_SP_PUT)
> > > > > > > +		rg_flags |= RING_F_SP_ENQ;
> > > > > > > +	if (mp->flags & MEMPOOL_F_SC_GET)
> > > > > > > +		rg_flags |= RING_F_SC_DEQ;
> > > > > > > +
> > > > > > > +	return ring_alloc(mp, rg_flags);
> > > > > > > +}
> > > > > > > +
> > > > > > > +static int
> > > > > > > +rts_ring_alloc(struct rte_mempool *mp)
> > > > > > > +{
> > > > > > > +	if ((mp->flags & (MEMPOOL_F_SP_PUT | MEMPOOL_F_SC_GET)) != 0)
> > > > > > > +		return -EINVAL;
> > > > > >
> > > > > > Why do we need this? It is a problem to allow sc/sp in this mode (even
> > > > > > if it's not optimal)?
> > > > >
> > > > > These new sync modes (RTS, HTS) are for MT.
> > > > > For SP/SC - there is simply no point to use MT sync modes.
> > > > > I suppose there are few choices:
> > > > > 1. Make F_SP_PUT/F_SC_GET flags silently override expected ops behaviour
> > > > >    and create actual ring with ST sync mode for prod/cons.
> > > > > 2. Report an error.
> > > > > 3. Silently ignore these flags.
> > > > >
> > > > > As I can see for  "ring_mp_mc" ops, we doing #1,
> > > > > while for "stack" we are doing #3.
> > > > > For RTS/HTS I chosoe #2, as it seems cleaner to me.
> > > > > Any thoughts from your side what preferable behaviour should be?
> > > >
> > > > The F_SP_PUT/F_SC_GET are only used in rte_mempool_create() to select
> > > > the default ops among (ring_sp_sc, ring_mp_sc, ring_sp_mc,
> > > > ring_mp_mc).
> > >
> > > As I understand, nothing prevents user from doing:
> > >
> > > mp = rte_mempool_create_empty(name, n, elt_size, cache_size,
> > >                  sizeof(struct rte_pktmbuf_pool_private), socket_id, 0);
> >
> > Apologies, hit send accidently.
> > I meant user can do:
> >
> > mp = rte_mempool_create_empty(..., F_SP_PUT | F_SC_GET);
> > rte_mempool_set_ops_byname(mp, "ring_mp_mc", NULL);
> >
> > An in that case, he'll get SP/SC ring underneath.
> 
> It looks it's not the case. Since commit 449c49b93a6b ("mempool: support
> handler operations"), the flags SP_PUT/SC_GET are converted into a call
> to rte_mempool_set_ops_byname() in rte_mempool_create() only.
> 
> In rte_mempool_create_empty(), these flags are ignored. It is expected
> that the user calls rte_mempool_set_ops_byname() by itself.

As I understand the code - not exactly.
rte_mempool_create_empty() doesn't make any specific actions based on 'flags' value,
but it does store it's value inside mp->flags.
Later, when mempool_ops_alloc_once() is called these flags will be used by
common_ring_alloc() and might override selected by ops ring behaviour.

> 
> I don't think it is a good behavior:
> 
> 1/ The documentation of rte_mempool_create_empty() does not say that the
>    flags are ignored, and a user can expect that F_SP_PUT | F_SC_GET
>    sets the default ops like rte_mempool_create().
> 
> 2/ If rte_mempool_set_ops_byname() is not called after
>    rte_mempool_create_empty() (and it looks it happens in dpdk's code),
>    the default ops are the ones registered at index 0. This depends on
>    the link order.
> 
> So I propose to move the following code in
> rte_mempool_create_empty().
> 
> 	if ((flags & MEMPOOL_F_SP_PUT) && (flags & MEMPOOL_F_SC_GET))
> 		ret = rte_mempool_set_ops_byname(mp, "ring_sp_sc", NULL);
> 	else if (flags & MEMPOOL_F_SP_PUT)
> 		ret = rte_mempool_set_ops_byname(mp, "ring_sp_mc", NULL);
> 	else if (flags & MEMPOOL_F_SC_GET)
> 		ret = rte_mempool_set_ops_byname(mp, "ring_mp_sc", NULL);
> 	else
> 		ret = rte_mempool_set_ops_byname(mp, "ring_mp_mc", NULL);
> 
> What do you think?

I think it will be a good thing - as in that case we'll always have
"ring_mp_mc" selected as default one.
As another thought, it porbably would be good to deprecate and later remove
MEMPOOL_F_SP_PUT and MEMPOOL_F_SC_GET completely.
These days user can select this behaviour via mempool ops and such dualism
just makes things more error-prone and harder to maintain.
Especially as we don't have clear policy what should be the higher priority
for sync mode selection: mempool ops or flags.
Olivier Matz July 13, 2020, 3 p.m. UTC | #8
On Mon, Jul 13, 2020 at 02:46:35PM +0000, Ananyev, Konstantin wrote:
> Hi Olivier,
> 
> > Hi Konstantin,
> > 
> > On Fri, Jul 10, 2020 at 03:20:12PM +0000, Ananyev, Konstantin wrote:
> > >
> > >
> > > >
> > > > Hi Olivier,
> > > >
> > > > > Hi Konstantin,
> > > > >
> > > > > On Thu, Jul 09, 2020 at 05:55:30PM +0000, Ananyev, Konstantin wrote:
> > > > > > Hi Olivier,
> > > > > >
> > > > > > > Hi Konstantin,
> > > > > > >
> > > > > > > On Mon, Jun 29, 2020 at 05:10:24PM +0100, Konstantin Ananyev wrote:
> > > > > > > > v2:
> > > > > > > >  - update Release Notes (as per comments)
> > > > > > > >
> > > > > > > > Two new sync modes were introduced into rte_ring:
> > > > > > > > relaxed tail sync (RTS) and head/tail sync (HTS).
> > > > > > > > This change provides user with ability to select these
> > > > > > > > modes for ring based mempool via mempool ops API.
> > > > > > > >
> > > > > > > > Signed-off-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
> > > > > > > > Acked-by: Gage Eads <gage.eads@intel.com>
> > > > > > > > ---
> > > > > > > >  doc/guides/rel_notes/release_20_08.rst  |  6 ++
> > > > > > > >  drivers/mempool/ring/rte_mempool_ring.c | 97 ++++++++++++++++++++++---
> > > > > > > >  2 files changed, 94 insertions(+), 9 deletions(-)
> > > > > > > >
> > > > > > > > diff --git a/doc/guides/rel_notes/release_20_08.rst b/doc/guides/rel_notes/release_20_08.rst
> > > > > > > > index eaaf11c37..7bdcf3aac 100644
> > > > > > > > --- a/doc/guides/rel_notes/release_20_08.rst
> > > > > > > > +++ b/doc/guides/rel_notes/release_20_08.rst
> > > > > > > > @@ -84,6 +84,12 @@ New Features
> > > > > > > >    * Dump ``rte_flow`` memory consumption.
> > > > > > > >    * Measure packet per second forwarding.
> > > > > > > >
> > > > > > > > +* **Added support for new sync modes into mempool ring driver.**
> > > > > > > > +
> > > > > > > > +  Added ability to select new ring synchronisation modes:
> > > > > > > > +  ``relaxed tail sync (ring_mt_rts)`` and ``head/tail sync (ring_mt_hts)``
> > > > > > > > +  via mempool ops API.
> > > > > > > > +
> > > > > > > >
> > > > > > > >  Removed Items
> > > > > > > >  -------------
> > > > > > > > diff --git a/drivers/mempool/ring/rte_mempool_ring.c b/drivers/mempool/ring/rte_mempool_ring.c
> > > > > > > > index bc123fc52..15ec7dee7 100644
> > > > > > > > --- a/drivers/mempool/ring/rte_mempool_ring.c
> > > > > > > > +++ b/drivers/mempool/ring/rte_mempool_ring.c
> > > > > > > > @@ -25,6 +25,22 @@ common_ring_sp_enqueue(struct rte_mempool *mp, void * const *obj_table,
> > > > > > > >  			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > > > > >  }
> > > > > > > >
> > > > > > > > +static int
> > > > > > > > +rts_ring_mp_enqueue(struct rte_mempool *mp, void * const *obj_table,
> > > > > > > > +	unsigned int n)
> > > > > > > > +{
> > > > > > > > +	return rte_ring_mp_rts_enqueue_bulk(mp->pool_data,
> > > > > > > > +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > > > > > +}
> > > > > > > > +
> > > > > > > > +static int
> > > > > > > > +hts_ring_mp_enqueue(struct rte_mempool *mp, void * const *obj_table,
> > > > > > > > +	unsigned int n)
> > > > > > > > +{
> > > > > > > > +	return rte_ring_mp_hts_enqueue_bulk(mp->pool_data,
> > > > > > > > +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > > > > > +}
> > > > > > > > +
> > > > > > > >  static int
> > > > > > > >  common_ring_mc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned n)
> > > > > > > >  {
> > > > > > > > @@ -39,17 +55,30 @@ common_ring_sc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned n)
> > > > > > > >  			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > > > > >  }
> > > > > > > >
> > > > > > > > +static int
> > > > > > > > +rts_ring_mc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned int n)
> > > > > > > > +{
> > > > > > > > +	return rte_ring_mc_rts_dequeue_bulk(mp->pool_data,
> > > > > > > > +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > > > > > +}
> > > > > > > > +
> > > > > > > > +static int
> > > > > > > > +hts_ring_mc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned int n)
> > > > > > > > +{
> > > > > > > > +	return rte_ring_mc_hts_dequeue_bulk(mp->pool_data,
> > > > > > > > +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > > > > > +}
> > > > > > > > +
> > > > > > > >  static unsigned
> > > > > > > >  common_ring_get_count(const struct rte_mempool *mp)
> > > > > > > >  {
> > > > > > > >  	return rte_ring_count(mp->pool_data);
> > > > > > > >  }
> > > > > > > >
> > > > > > > > -
> > > > > > > >  static int
> > > > > > > > -common_ring_alloc(struct rte_mempool *mp)
> > > > > > > > +ring_alloc(struct rte_mempool *mp, uint32_t rg_flags)
> > > > > > > >  {
> > > > > > > > -	int rg_flags = 0, ret;
> > > > > > > > +	int ret;
> > > > > > > >  	char rg_name[RTE_RING_NAMESIZE];
> > > > > > > >  	struct rte_ring *r;
> > > > > > > >
> > > > > > > > @@ -60,12 +89,6 @@ common_ring_alloc(struct rte_mempool *mp)
> > > > > > > >  		return -rte_errno;
> > > > > > > >  	}
> > > > > > > >
> > > > > > > > -	/* ring flags */
> > > > > > > > -	if (mp->flags & MEMPOOL_F_SP_PUT)
> > > > > > > > -		rg_flags |= RING_F_SP_ENQ;
> > > > > > > > -	if (mp->flags & MEMPOOL_F_SC_GET)
> > > > > > > > -		rg_flags |= RING_F_SC_DEQ;
> > > > > > > > -
> > > > > > > >  	/*
> > > > > > > >  	 * Allocate the ring that will be used to store objects.
> > > > > > > >  	 * Ring functions will return appropriate errors if we are
> > > > > > > > @@ -82,6 +105,40 @@ common_ring_alloc(struct rte_mempool *mp)
> > > > > > > >  	return 0;
> > > > > > > >  }
> > > > > > > >
> > > > > > > > +static int
> > > > > > > > +common_ring_alloc(struct rte_mempool *mp)
> > > > > > > > +{
> > > > > > > > +	uint32_t rg_flags;
> > > > > > > > +
> > > > > > > > +	rg_flags = 0;
> > > > > > >
> > > > > > > Maybe it could go on the same line
> > > > > > >
> > > > > > > > +
> > > > > > > > +	/* ring flags */
> > > > > > >
> > > > > > > Not sure we need to keep this comment
> > > > > > >
> > > > > > > > +	if (mp->flags & MEMPOOL_F_SP_PUT)
> > > > > > > > +		rg_flags |= RING_F_SP_ENQ;
> > > > > > > > +	if (mp->flags & MEMPOOL_F_SC_GET)
> > > > > > > > +		rg_flags |= RING_F_SC_DEQ;
> > > > > > > > +
> > > > > > > > +	return ring_alloc(mp, rg_flags);
> > > > > > > > +}
> > > > > > > > +
> > > > > > > > +static int
> > > > > > > > +rts_ring_alloc(struct rte_mempool *mp)
> > > > > > > > +{
> > > > > > > > +	if ((mp->flags & (MEMPOOL_F_SP_PUT | MEMPOOL_F_SC_GET)) != 0)
> > > > > > > > +		return -EINVAL;
> > > > > > >
> > > > > > > Why do we need this? It is a problem to allow sc/sp in this mode (even
> > > > > > > if it's not optimal)?
> > > > > >
> > > > > > These new sync modes (RTS, HTS) are for MT.
> > > > > > For SP/SC - there is simply no point to use MT sync modes.
> > > > > > I suppose there are few choices:
> > > > > > 1. Make F_SP_PUT/F_SC_GET flags silently override expected ops behaviour
> > > > > >    and create actual ring with ST sync mode for prod/cons.
> > > > > > 2. Report an error.
> > > > > > 3. Silently ignore these flags.
> > > > > >
> > > > > > As I can see for  "ring_mp_mc" ops, we doing #1,
> > > > > > while for "stack" we are doing #3.
> > > > > > For RTS/HTS I chosoe #2, as it seems cleaner to me.
> > > > > > Any thoughts from your side what preferable behaviour should be?
> > > > >
> > > > > The F_SP_PUT/F_SC_GET are only used in rte_mempool_create() to select
> > > > > the default ops among (ring_sp_sc, ring_mp_sc, ring_sp_mc,
> > > > > ring_mp_mc).
> > > >
> > > > As I understand, nothing prevents user from doing:
> > > >
> > > > mp = rte_mempool_create_empty(name, n, elt_size, cache_size,
> > > >                  sizeof(struct rte_pktmbuf_pool_private), socket_id, 0);
> > >
> > > Apologies, hit send accidently.
> > > I meant user can do:
> > >
> > > mp = rte_mempool_create_empty(..., F_SP_PUT | F_SC_GET);
> > > rte_mempool_set_ops_byname(mp, "ring_mp_mc", NULL);
> > >
> > > An in that case, he'll get SP/SC ring underneath.
> > 
> > It looks it's not the case. Since commit 449c49b93a6b ("mempool: support
> > handler operations"), the flags SP_PUT/SC_GET are converted into a call
> > to rte_mempool_set_ops_byname() in rte_mempool_create() only.
> > 
> > In rte_mempool_create_empty(), these flags are ignored. It is expected
> > that the user calls rte_mempool_set_ops_byname() by itself.
> 
> As I understand the code - not exactly.
> rte_mempool_create_empty() doesn't make any specific actions based on 'flags' value,
> but it does store it's value inside mp->flags.
> Later, when mempool_ops_alloc_once() is called these flags will be used by
> common_ring_alloc() and might override selected by ops ring behaviour.
> 
> > 
> > I don't think it is a good behavior:
> > 
> > 1/ The documentation of rte_mempool_create_empty() does not say that the
> >    flags are ignored, and a user can expect that F_SP_PUT | F_SC_GET
> >    sets the default ops like rte_mempool_create().
> > 
> > 2/ If rte_mempool_set_ops_byname() is not called after
> >    rte_mempool_create_empty() (and it looks it happens in dpdk's code),
> >    the default ops are the ones registered at index 0. This depends on
> >    the link order.
> > 
> > So I propose to move the following code in
> > rte_mempool_create_empty().
> > 
> > 	if ((flags & MEMPOOL_F_SP_PUT) && (flags & MEMPOOL_F_SC_GET))
> > 		ret = rte_mempool_set_ops_byname(mp, "ring_sp_sc", NULL);
> > 	else if (flags & MEMPOOL_F_SP_PUT)
> > 		ret = rte_mempool_set_ops_byname(mp, "ring_sp_mc", NULL);
> > 	else if (flags & MEMPOOL_F_SC_GET)
> > 		ret = rte_mempool_set_ops_byname(mp, "ring_mp_sc", NULL);
> > 	else
> > 		ret = rte_mempool_set_ops_byname(mp, "ring_mp_mc", NULL);
> > 
> > What do you think?
> 
> I think it will be a good thing - as in that case we'll always have
> "ring_mp_mc" selected as default one.
> As another thought, it porbably would be good to deprecate and later remove
> MEMPOOL_F_SP_PUT and MEMPOOL_F_SC_GET completely.
> These days user can select this behaviour via mempool ops and such dualism
> just makes things more error-prone and harder to maintain.
> Especially as we don't have clear policy what should be the higher priority
> for sync mode selection: mempool ops or flags. 
> 

I'll tend to agree, however it would mean deprecate rte_mempool_create()
too, because we wouldn't be able to set ops with it. Or we would have to
add a 12th (!) argument to the function, to set the ops name.

I don't like having that many arguments to this function, but it seems
it is widely used, probably because it is just one function call (vs
create_empty + set_ops + populate). So adding a "ops_name" argument is
maybe the right thing to do, given we can keep abi compat.
Ananyev, Konstantin July 13, 2020, 4:29 p.m. UTC | #9
> On Mon, Jul 13, 2020 at 02:46:35PM +0000, Ananyev, Konstantin wrote:
> > Hi Olivier,
> >
> > > Hi Konstantin,
> > >
> > > On Fri, Jul 10, 2020 at 03:20:12PM +0000, Ananyev, Konstantin wrote:
> > > >
> > > >
> > > > >
> > > > > Hi Olivier,
> > > > >
> > > > > > Hi Konstantin,
> > > > > >
> > > > > > On Thu, Jul 09, 2020 at 05:55:30PM +0000, Ananyev, Konstantin wrote:
> > > > > > > Hi Olivier,
> > > > > > >
> > > > > > > > Hi Konstantin,
> > > > > > > >
> > > > > > > > On Mon, Jun 29, 2020 at 05:10:24PM +0100, Konstantin Ananyev wrote:
> > > > > > > > > v2:
> > > > > > > > >  - update Release Notes (as per comments)
> > > > > > > > >
> > > > > > > > > Two new sync modes were introduced into rte_ring:
> > > > > > > > > relaxed tail sync (RTS) and head/tail sync (HTS).
> > > > > > > > > This change provides user with ability to select these
> > > > > > > > > modes for ring based mempool via mempool ops API.
> > > > > > > > >
> > > > > > > > > Signed-off-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
> > > > > > > > > Acked-by: Gage Eads <gage.eads@intel.com>
> > > > > > > > > ---
> > > > > > > > >  doc/guides/rel_notes/release_20_08.rst  |  6 ++
> > > > > > > > >  drivers/mempool/ring/rte_mempool_ring.c | 97 ++++++++++++++++++++++---
> > > > > > > > >  2 files changed, 94 insertions(+), 9 deletions(-)
> > > > > > > > >
> > > > > > > > > diff --git a/doc/guides/rel_notes/release_20_08.rst b/doc/guides/rel_notes/release_20_08.rst
> > > > > > > > > index eaaf11c37..7bdcf3aac 100644
> > > > > > > > > --- a/doc/guides/rel_notes/release_20_08.rst
> > > > > > > > > +++ b/doc/guides/rel_notes/release_20_08.rst
> > > > > > > > > @@ -84,6 +84,12 @@ New Features
> > > > > > > > >    * Dump ``rte_flow`` memory consumption.
> > > > > > > > >    * Measure packet per second forwarding.
> > > > > > > > >
> > > > > > > > > +* **Added support for new sync modes into mempool ring driver.**
> > > > > > > > > +
> > > > > > > > > +  Added ability to select new ring synchronisation modes:
> > > > > > > > > +  ``relaxed tail sync (ring_mt_rts)`` and ``head/tail sync (ring_mt_hts)``
> > > > > > > > > +  via mempool ops API.
> > > > > > > > > +
> > > > > > > > >
> > > > > > > > >  Removed Items
> > > > > > > > >  -------------
> > > > > > > > > diff --git a/drivers/mempool/ring/rte_mempool_ring.c b/drivers/mempool/ring/rte_mempool_ring.c
> > > > > > > > > index bc123fc52..15ec7dee7 100644
> > > > > > > > > --- a/drivers/mempool/ring/rte_mempool_ring.c
> > > > > > > > > +++ b/drivers/mempool/ring/rte_mempool_ring.c
> > > > > > > > > @@ -25,6 +25,22 @@ common_ring_sp_enqueue(struct rte_mempool *mp, void * const *obj_table,
> > > > > > > > >  			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > > > > > >  }
> > > > > > > > >
> > > > > > > > > +static int
> > > > > > > > > +rts_ring_mp_enqueue(struct rte_mempool *mp, void * const *obj_table,
> > > > > > > > > +	unsigned int n)
> > > > > > > > > +{
> > > > > > > > > +	return rte_ring_mp_rts_enqueue_bulk(mp->pool_data,
> > > > > > > > > +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > > > > > > +}
> > > > > > > > > +
> > > > > > > > > +static int
> > > > > > > > > +hts_ring_mp_enqueue(struct rte_mempool *mp, void * const *obj_table,
> > > > > > > > > +	unsigned int n)
> > > > > > > > > +{
> > > > > > > > > +	return rte_ring_mp_hts_enqueue_bulk(mp->pool_data,
> > > > > > > > > +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > > > > > > +}
> > > > > > > > > +
> > > > > > > > >  static int
> > > > > > > > >  common_ring_mc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned n)
> > > > > > > > >  {
> > > > > > > > > @@ -39,17 +55,30 @@ common_ring_sc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned n)
> > > > > > > > >  			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > > > > > >  }
> > > > > > > > >
> > > > > > > > > +static int
> > > > > > > > > +rts_ring_mc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned int n)
> > > > > > > > > +{
> > > > > > > > > +	return rte_ring_mc_rts_dequeue_bulk(mp->pool_data,
> > > > > > > > > +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > > > > > > +}
> > > > > > > > > +
> > > > > > > > > +static int
> > > > > > > > > +hts_ring_mc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned int n)
> > > > > > > > > +{
> > > > > > > > > +	return rte_ring_mc_hts_dequeue_bulk(mp->pool_data,
> > > > > > > > > +			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
> > > > > > > > > +}
> > > > > > > > > +
> > > > > > > > >  static unsigned
> > > > > > > > >  common_ring_get_count(const struct rte_mempool *mp)
> > > > > > > > >  {
> > > > > > > > >  	return rte_ring_count(mp->pool_data);
> > > > > > > > >  }
> > > > > > > > >
> > > > > > > > > -
> > > > > > > > >  static int
> > > > > > > > > -common_ring_alloc(struct rte_mempool *mp)
> > > > > > > > > +ring_alloc(struct rte_mempool *mp, uint32_t rg_flags)
> > > > > > > > >  {
> > > > > > > > > -	int rg_flags = 0, ret;
> > > > > > > > > +	int ret;
> > > > > > > > >  	char rg_name[RTE_RING_NAMESIZE];
> > > > > > > > >  	struct rte_ring *r;
> > > > > > > > >
> > > > > > > > > @@ -60,12 +89,6 @@ common_ring_alloc(struct rte_mempool *mp)
> > > > > > > > >  		return -rte_errno;
> > > > > > > > >  	}
> > > > > > > > >
> > > > > > > > > -	/* ring flags */
> > > > > > > > > -	if (mp->flags & MEMPOOL_F_SP_PUT)
> > > > > > > > > -		rg_flags |= RING_F_SP_ENQ;
> > > > > > > > > -	if (mp->flags & MEMPOOL_F_SC_GET)
> > > > > > > > > -		rg_flags |= RING_F_SC_DEQ;
> > > > > > > > > -
> > > > > > > > >  	/*
> > > > > > > > >  	 * Allocate the ring that will be used to store objects.
> > > > > > > > >  	 * Ring functions will return appropriate errors if we are
> > > > > > > > > @@ -82,6 +105,40 @@ common_ring_alloc(struct rte_mempool *mp)
> > > > > > > > >  	return 0;
> > > > > > > > >  }
> > > > > > > > >
> > > > > > > > > +static int
> > > > > > > > > +common_ring_alloc(struct rte_mempool *mp)
> > > > > > > > > +{
> > > > > > > > > +	uint32_t rg_flags;
> > > > > > > > > +
> > > > > > > > > +	rg_flags = 0;
> > > > > > > >
> > > > > > > > Maybe it could go on the same line
> > > > > > > >
> > > > > > > > > +
> > > > > > > > > +	/* ring flags */
> > > > > > > >
> > > > > > > > Not sure we need to keep this comment
> > > > > > > >
> > > > > > > > > +	if (mp->flags & MEMPOOL_F_SP_PUT)
> > > > > > > > > +		rg_flags |= RING_F_SP_ENQ;
> > > > > > > > > +	if (mp->flags & MEMPOOL_F_SC_GET)
> > > > > > > > > +		rg_flags |= RING_F_SC_DEQ;
> > > > > > > > > +
> > > > > > > > > +	return ring_alloc(mp, rg_flags);
> > > > > > > > > +}
> > > > > > > > > +
> > > > > > > > > +static int
> > > > > > > > > +rts_ring_alloc(struct rte_mempool *mp)
> > > > > > > > > +{
> > > > > > > > > +	if ((mp->flags & (MEMPOOL_F_SP_PUT | MEMPOOL_F_SC_GET)) != 0)
> > > > > > > > > +		return -EINVAL;
> > > > > > > >
> > > > > > > > Why do we need this? It is a problem to allow sc/sp in this mode (even
> > > > > > > > if it's not optimal)?
> > > > > > >
> > > > > > > These new sync modes (RTS, HTS) are for MT.
> > > > > > > For SP/SC - there is simply no point to use MT sync modes.
> > > > > > > I suppose there are few choices:
> > > > > > > 1. Make F_SP_PUT/F_SC_GET flags silently override expected ops behaviour
> > > > > > >    and create actual ring with ST sync mode for prod/cons.
> > > > > > > 2. Report an error.
> > > > > > > 3. Silently ignore these flags.
> > > > > > >
> > > > > > > As I can see for  "ring_mp_mc" ops, we doing #1,
> > > > > > > while for "stack" we are doing #3.
> > > > > > > For RTS/HTS I chosoe #2, as it seems cleaner to me.
> > > > > > > Any thoughts from your side what preferable behaviour should be?
> > > > > >
> > > > > > The F_SP_PUT/F_SC_GET are only used in rte_mempool_create() to select
> > > > > > the default ops among (ring_sp_sc, ring_mp_sc, ring_sp_mc,
> > > > > > ring_mp_mc).
> > > > >
> > > > > As I understand, nothing prevents user from doing:
> > > > >
> > > > > mp = rte_mempool_create_empty(name, n, elt_size, cache_size,
> > > > >                  sizeof(struct rte_pktmbuf_pool_private), socket_id, 0);
> > > >
> > > > Apologies, hit send accidently.
> > > > I meant user can do:
> > > >
> > > > mp = rte_mempool_create_empty(..., F_SP_PUT | F_SC_GET);
> > > > rte_mempool_set_ops_byname(mp, "ring_mp_mc", NULL);
> > > >
> > > > An in that case, he'll get SP/SC ring underneath.
> > >
> > > It looks it's not the case. Since commit 449c49b93a6b ("mempool: support
> > > handler operations"), the flags SP_PUT/SC_GET are converted into a call
> > > to rte_mempool_set_ops_byname() in rte_mempool_create() only.
> > >
> > > In rte_mempool_create_empty(), these flags are ignored. It is expected
> > > that the user calls rte_mempool_set_ops_byname() by itself.
> >
> > As I understand the code - not exactly.
> > rte_mempool_create_empty() doesn't make any specific actions based on 'flags' value,
> > but it does store it's value inside mp->flags.
> > Later, when mempool_ops_alloc_once() is called these flags will be used by
> > common_ring_alloc() and might override selected by ops ring behaviour.
> >
> > >
> > > I don't think it is a good behavior:
> > >
> > > 1/ The documentation of rte_mempool_create_empty() does not say that the
> > >    flags are ignored, and a user can expect that F_SP_PUT | F_SC_GET
> > >    sets the default ops like rte_mempool_create().
> > >
> > > 2/ If rte_mempool_set_ops_byname() is not called after
> > >    rte_mempool_create_empty() (and it looks it happens in dpdk's code),
> > >    the default ops are the ones registered at index 0. This depends on
> > >    the link order.
> > >
> > > So I propose to move the following code in
> > > rte_mempool_create_empty().
> > >
> > > 	if ((flags & MEMPOOL_F_SP_PUT) && (flags & MEMPOOL_F_SC_GET))
> > > 		ret = rte_mempool_set_ops_byname(mp, "ring_sp_sc", NULL);
> > > 	else if (flags & MEMPOOL_F_SP_PUT)
> > > 		ret = rte_mempool_set_ops_byname(mp, "ring_sp_mc", NULL);
> > > 	else if (flags & MEMPOOL_F_SC_GET)
> > > 		ret = rte_mempool_set_ops_byname(mp, "ring_mp_sc", NULL);
> > > 	else
> > > 		ret = rte_mempool_set_ops_byname(mp, "ring_mp_mc", NULL);
> > >
> > > What do you think?
> >
> > I think it will be a good thing - as in that case we'll always have
> > "ring_mp_mc" selected as default one.
> > As another thought, it porbably would be good to deprecate and later remove
> > MEMPOOL_F_SP_PUT and MEMPOOL_F_SC_GET completely.
> > These days user can select this behaviour via mempool ops and such dualism
> > just makes things more error-prone and harder to maintain.
> > Especially as we don't have clear policy what should be the higher priority
> > for sync mode selection: mempool ops or flags.
> >
> 
> I'll tend to agree, however it would mean deprecate rte_mempool_create()
> too, because we wouldn't be able to set ops with it. Or we would have to
> add a 12th (!) argument to the function, to set the ops name.
> 
> I don't like having that many arguments to this function, but it seems
> it is widely used, probably because it is just one function call (vs
> create_empty + set_ops + populate). So adding a "ops_name" argument is
> maybe the right thing to do, given we can keep abi compat.

My thought was - just keep rte_mempool_create()
parameter list as it is, and always set ops to "ring_mp_mc" for it.
Users who'd like some other ops would force to use
create_empty+set_ops+populate.
That's pretty much the same what we have right now,
the only diff will be ring with SP/SC mode.

Patch
diff mbox series

diff --git a/doc/guides/rel_notes/release_20_08.rst b/doc/guides/rel_notes/release_20_08.rst
index eaaf11c37..7bdcf3aac 100644
--- a/doc/guides/rel_notes/release_20_08.rst
+++ b/doc/guides/rel_notes/release_20_08.rst
@@ -84,6 +84,12 @@  New Features
   * Dump ``rte_flow`` memory consumption.
   * Measure packet per second forwarding.
 
+* **Added support for new sync modes into mempool ring driver.**
+
+  Added ability to select new ring synchronisation modes:
+  ``relaxed tail sync (ring_mt_rts)`` and ``head/tail sync (ring_mt_hts)``
+  via mempool ops API.
+
 
 Removed Items
 -------------
diff --git a/drivers/mempool/ring/rte_mempool_ring.c b/drivers/mempool/ring/rte_mempool_ring.c
index bc123fc52..15ec7dee7 100644
--- a/drivers/mempool/ring/rte_mempool_ring.c
+++ b/drivers/mempool/ring/rte_mempool_ring.c
@@ -25,6 +25,22 @@  common_ring_sp_enqueue(struct rte_mempool *mp, void * const *obj_table,
 			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
 }
 
+static int
+rts_ring_mp_enqueue(struct rte_mempool *mp, void * const *obj_table,
+	unsigned int n)
+{
+	return rte_ring_mp_rts_enqueue_bulk(mp->pool_data,
+			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
+}
+
+static int
+hts_ring_mp_enqueue(struct rte_mempool *mp, void * const *obj_table,
+	unsigned int n)
+{
+	return rte_ring_mp_hts_enqueue_bulk(mp->pool_data,
+			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
+}
+
 static int
 common_ring_mc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned n)
 {
@@ -39,17 +55,30 @@  common_ring_sc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned n)
 			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
 }
 
+static int
+rts_ring_mc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned int n)
+{
+	return rte_ring_mc_rts_dequeue_bulk(mp->pool_data,
+			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
+}
+
+static int
+hts_ring_mc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned int n)
+{
+	return rte_ring_mc_hts_dequeue_bulk(mp->pool_data,
+			obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
+}
+
 static unsigned
 common_ring_get_count(const struct rte_mempool *mp)
 {
 	return rte_ring_count(mp->pool_data);
 }
 
-
 static int
-common_ring_alloc(struct rte_mempool *mp)
+ring_alloc(struct rte_mempool *mp, uint32_t rg_flags)
 {
-	int rg_flags = 0, ret;
+	int ret;
 	char rg_name[RTE_RING_NAMESIZE];
 	struct rte_ring *r;
 
@@ -60,12 +89,6 @@  common_ring_alloc(struct rte_mempool *mp)
 		return -rte_errno;
 	}
 
-	/* ring flags */
-	if (mp->flags & MEMPOOL_F_SP_PUT)
-		rg_flags |= RING_F_SP_ENQ;
-	if (mp->flags & MEMPOOL_F_SC_GET)
-		rg_flags |= RING_F_SC_DEQ;
-
 	/*
 	 * Allocate the ring that will be used to store objects.
 	 * Ring functions will return appropriate errors if we are
@@ -82,6 +105,40 @@  common_ring_alloc(struct rte_mempool *mp)
 	return 0;
 }
 
+static int
+common_ring_alloc(struct rte_mempool *mp)
+{
+	uint32_t rg_flags;
+
+	rg_flags = 0;
+
+	/* ring flags */
+	if (mp->flags & MEMPOOL_F_SP_PUT)
+		rg_flags |= RING_F_SP_ENQ;
+	if (mp->flags & MEMPOOL_F_SC_GET)
+		rg_flags |= RING_F_SC_DEQ;
+
+	return ring_alloc(mp, rg_flags);
+}
+
+static int
+rts_ring_alloc(struct rte_mempool *mp)
+{
+	if ((mp->flags & (MEMPOOL_F_SP_PUT | MEMPOOL_F_SC_GET)) != 0)
+		return -EINVAL;
+
+	return ring_alloc(mp, RING_F_MP_RTS_ENQ | RING_F_MC_RTS_DEQ);
+}
+
+static int
+hts_ring_alloc(struct rte_mempool *mp)
+{
+	if ((mp->flags & (MEMPOOL_F_SP_PUT | MEMPOOL_F_SC_GET)) != 0)
+		return -EINVAL;
+
+	return ring_alloc(mp, RING_F_MP_HTS_ENQ | RING_F_MC_HTS_DEQ);
+}
+
 static void
 common_ring_free(struct rte_mempool *mp)
 {
@@ -130,7 +187,29 @@  static const struct rte_mempool_ops ops_sp_mc = {
 	.get_count = common_ring_get_count,
 };
 
+/* ops for mempool with ring in MT_RTS sync mode */
+static const struct rte_mempool_ops ops_mt_rts = {
+	.name = "ring_mt_rts",
+	.alloc = rts_ring_alloc,
+	.free = common_ring_free,
+	.enqueue = rts_ring_mp_enqueue,
+	.dequeue = rts_ring_mc_dequeue,
+	.get_count = common_ring_get_count,
+};
+
+/* ops for mempool with ring in MT_HTS sync mode */
+static const struct rte_mempool_ops ops_mt_hts = {
+	.name = "ring_mt_hts",
+	.alloc = hts_ring_alloc,
+	.free = common_ring_free,
+	.enqueue = hts_ring_mp_enqueue,
+	.dequeue = hts_ring_mc_dequeue,
+	.get_count = common_ring_get_count,
+};
+
 MEMPOOL_REGISTER_OPS(ops_mp_mc);
 MEMPOOL_REGISTER_OPS(ops_sp_sc);
 MEMPOOL_REGISTER_OPS(ops_mp_sc);
 MEMPOOL_REGISTER_OPS(ops_sp_mc);
+MEMPOOL_REGISTER_OPS(ops_mt_rts);
+MEMPOOL_REGISTER_OPS(ops_mt_hts);