diff mbox series

[RFC,v3,4/5] lib/bpf: use wait event scheme for Rx/Tx iteration

Message ID 20210926063302.1541193-5-feifei.wang2@arm.com (mailing list archive)
State New
Delegated to: David Marchand
Headers show
Series add new definitions for wait scheme | expand

Checks

Context Check Description
ci/checkpatch success coding style OK

Commit Message

Feifei Wang Sept. 26, 2021, 6:33 a.m. UTC
Instead of polling for cbi->use to be updated, use wait event scheme.

Signed-off-by: Feifei Wang <feifei.wang2@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
---
 lib/bpf/bpf_pkt.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

Comments

Ananyev, Konstantin Oct. 7, 2021, 3:50 p.m. UTC | #1
> 
> Signed-off-by: Feifei Wang <feifei.wang2@arm.com>
> Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> ---
>  lib/bpf/bpf_pkt.c | 9 +++------
>  1 file changed, 3 insertions(+), 6 deletions(-)
> 
> diff --git a/lib/bpf/bpf_pkt.c b/lib/bpf/bpf_pkt.c
> index 6e8248f0d6..3af15ae97b 100644
> --- a/lib/bpf/bpf_pkt.c
> +++ b/lib/bpf/bpf_pkt.c
> @@ -113,7 +113,7 @@ bpf_eth_cbi_unuse(struct bpf_eth_cbi *cbi)
>  static void
>  bpf_eth_cbi_wait(const struct bpf_eth_cbi *cbi)
>  {
> -	uint32_t nuse, puse;
> +	uint32_t puse;
> 
>  	/* make sure all previous loads and stores are completed */
>  	rte_smp_mb();
> @@ -122,11 +122,8 @@ bpf_eth_cbi_wait(const struct bpf_eth_cbi *cbi)
> 
>  	/* in use, busy wait till current RX/TX iteration is finished */
>  	if ((puse & BPF_ETH_CBI_INUSE) != 0) {
> -		do {
> -			rte_pause();
> -			rte_compiler_barrier();
> -			nuse = cbi->use;
> -		} while (nuse == puse);
> +		rte_compiler_barrier();
> +		rte_wait_event_32(&cbi->use, UINT_MAX, puse, ==, __ATOMIC_RELAXED);

If we do use atomic load, while we still need a compiler_barrier() here?

>  	}
>  }
> 
> --
> 2.25.1
Ananyev, Konstantin Oct. 7, 2021, 5:40 p.m. UTC | #2
> -----Original Message-----
> From: Ananyev, Konstantin
> Sent: Thursday, October 7, 2021 4:50 PM
> To: Feifei Wang <feifei.wang2@arm.com>
> Cc: dev@dpdk.org; nd@arm.com; Ruifeng Wang <ruifeng.wang@arm.com>
> Subject: RE: [RFC PATCH v3 4/5] lib/bpf: use wait event scheme for Rx/Tx iteration
> 
> 
> 
> >
> > Signed-off-by: Feifei Wang <feifei.wang2@arm.com>
> > Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> > ---
> >  lib/bpf/bpf_pkt.c | 9 +++------
> >  1 file changed, 3 insertions(+), 6 deletions(-)
> >
> > diff --git a/lib/bpf/bpf_pkt.c b/lib/bpf/bpf_pkt.c
> > index 6e8248f0d6..3af15ae97b 100644
> > --- a/lib/bpf/bpf_pkt.c
> > +++ b/lib/bpf/bpf_pkt.c
> > @@ -113,7 +113,7 @@ bpf_eth_cbi_unuse(struct bpf_eth_cbi *cbi)
> >  static void
> >  bpf_eth_cbi_wait(const struct bpf_eth_cbi *cbi)
> >  {
> > -	uint32_t nuse, puse;
> > +	uint32_t puse;
> >
> >  	/* make sure all previous loads and stores are completed */
> >  	rte_smp_mb();
> > @@ -122,11 +122,8 @@ bpf_eth_cbi_wait(const struct bpf_eth_cbi *cbi)
> >
> >  	/* in use, busy wait till current RX/TX iteration is finished */
> >  	if ((puse & BPF_ETH_CBI_INUSE) != 0) {
> > -		do {
> > -			rte_pause();
> > -			rte_compiler_barrier();
> > -			nuse = cbi->use;
> > -		} while (nuse == puse);
> > +		rte_compiler_barrier();
> > +		rte_wait_event_32(&cbi->use, UINT_MAX, puse, ==, __ATOMIC_RELAXED);

Probably UINT32_MAX will be a bit better here.

> 
> If we do use atomic load, while we still need a compiler_barrier() here?
> 
> >  	}
> >  }
> >
> > --
> > 2.25.1
diff mbox series

Patch

diff --git a/lib/bpf/bpf_pkt.c b/lib/bpf/bpf_pkt.c
index 6e8248f0d6..3af15ae97b 100644
--- a/lib/bpf/bpf_pkt.c
+++ b/lib/bpf/bpf_pkt.c
@@ -113,7 +113,7 @@  bpf_eth_cbi_unuse(struct bpf_eth_cbi *cbi)
 static void
 bpf_eth_cbi_wait(const struct bpf_eth_cbi *cbi)
 {
-	uint32_t nuse, puse;
+	uint32_t puse;
 
 	/* make sure all previous loads and stores are completed */
 	rte_smp_mb();
@@ -122,11 +122,8 @@  bpf_eth_cbi_wait(const struct bpf_eth_cbi *cbi)
 
 	/* in use, busy wait till current RX/TX iteration is finished */
 	if ((puse & BPF_ETH_CBI_INUSE) != 0) {
-		do {
-			rte_pause();
-			rte_compiler_barrier();
-			nuse = cbi->use;
-		} while (nuse == puse);
+		rte_compiler_barrier();
+		rte_wait_event_32(&cbi->use, UINT_MAX, puse, ==, __ATOMIC_RELAXED);
 	}
 }