[dpdk-dev,v2,1/3] virtio: conditional compilation cleanup

Message ID 1467371814-26754-2-git-send-email-jerin.jacob@caviumnetworks.com (mailing list archive)
State Superseded, archived
Delegated to: Yuanhan Liu
Headers

Commit Message

Jerin Jacob July 1, 2016, 11:16 a.m. UTC
  Removed unnecessary compile time dependency on "use_simple_rxtx".

Signed-off-by: Jerin Jacob <jerin.jacob@caviumnetworks.com>
---
 drivers/net/virtio/Makefile             |  3 ---
 drivers/net/virtio/virtio_pci.h         |  1 +
 drivers/net/virtio/virtio_rxtx.c        | 28 +++++++++-------------------
 drivers/net/virtio/virtio_rxtx.h        |  3 +--
 drivers/net/virtio/virtio_rxtx_simple.c |  8 ++++++--
 drivers/net/virtio/virtio_user_ethdev.c |  1 +
 6 files changed, 18 insertions(+), 26 deletions(-)
  

Comments

Yuanhan Liu July 4, 2016, 7:36 a.m. UTC | #1
On Fri, Jul 01, 2016 at 04:46:36PM +0530, Jerin Jacob wrote:
> @@ -494,9 +486,6 @@ virtio_dev_tx_queue_setup(struct rte_eth_dev *dev,
>  {
>  	uint8_t vtpci_queue_idx = 2 * queue_idx + VTNET_SQ_TQ_QUEUE_IDX;
>  
> -#ifdef RTE_MACHINE_CPUFLAG_SSSE3
> -	struct virtio_hw *hw = dev->data->dev_private;
> -#endif
>  	struct virtnet_tx *txvq;
>  	struct virtqueue *vq;
>  	uint16_t tx_free_thresh;
> @@ -511,13 +500,14 @@ virtio_dev_tx_queue_setup(struct rte_eth_dev *dev,
>  	}
>  
>  #ifdef RTE_MACHINE_CPUFLAG_SSSE3
> +	struct virtio_hw *hw = dev->data->dev_private;

I'd suggest to move above declaration to ...

>  	/* Use simple rx/tx func if single segment and no offloads */
>  	if ((tx_conf->txq_flags & VIRTIO_SIMPLE_FLAGS) == VIRTIO_SIMPLE_FLAGS &&
>  	     !vtpci_with_feature(hw, VIRTIO_NET_F_MRG_RXBUF)) {

here: we should try to avoid declaring vars in the middle of a code block.

	--yliu
  
Jerin Jacob July 4, 2016, 8:36 a.m. UTC | #2
On Mon, Jul 04, 2016 at 03:36:48PM +0800, Yuanhan Liu wrote:
> On Fri, Jul 01, 2016 at 04:46:36PM +0530, Jerin Jacob wrote:
> > @@ -494,9 +486,6 @@ virtio_dev_tx_queue_setup(struct rte_eth_dev *dev,
> >  {
> >  	uint8_t vtpci_queue_idx = 2 * queue_idx + VTNET_SQ_TQ_QUEUE_IDX;
> >  
> > -#ifdef RTE_MACHINE_CPUFLAG_SSSE3
> > -	struct virtio_hw *hw = dev->data->dev_private;
> > -#endif
> >  	struct virtnet_tx *txvq;
> >  	struct virtqueue *vq;
> >  	uint16_t tx_free_thresh;
> > @@ -511,13 +500,14 @@ virtio_dev_tx_queue_setup(struct rte_eth_dev *dev,
> >  	}
> >  
> >  #ifdef RTE_MACHINE_CPUFLAG_SSSE3
> > +	struct virtio_hw *hw = dev->data->dev_private;
> 
> I'd suggest to move above declaration to ...
> 
> >  	/* Use simple rx/tx func if single segment and no offloads */
> >  	if ((tx_conf->txq_flags & VIRTIO_SIMPLE_FLAGS) == VIRTIO_SIMPLE_FLAGS &&
> >  	     !vtpci_with_feature(hw, VIRTIO_NET_F_MRG_RXBUF)) {
> 
> here: we should try to avoid declaring vars in the middle of a code block.

Next patch in this series, moving all rxtx handler selection code to
separate function(virtio_update_rxtx_handler()) where declaration comes
as first line in the function.i.e the comment is taken care of in the
series.

> 
> 	--yliu
  
Yuanhan Liu July 4, 2016, 8:42 a.m. UTC | #3
On Mon, Jul 04, 2016 at 02:06:27PM +0530, Jerin Jacob wrote:
> On Mon, Jul 04, 2016 at 03:36:48PM +0800, Yuanhan Liu wrote:
> > On Fri, Jul 01, 2016 at 04:46:36PM +0530, Jerin Jacob wrote:
> > > @@ -494,9 +486,6 @@ virtio_dev_tx_queue_setup(struct rte_eth_dev *dev,
> > >  {
> > >  	uint8_t vtpci_queue_idx = 2 * queue_idx + VTNET_SQ_TQ_QUEUE_IDX;
> > >  
> > > -#ifdef RTE_MACHINE_CPUFLAG_SSSE3
> > > -	struct virtio_hw *hw = dev->data->dev_private;
> > > -#endif
> > >  	struct virtnet_tx *txvq;
> > >  	struct virtqueue *vq;
> > >  	uint16_t tx_free_thresh;
> > > @@ -511,13 +500,14 @@ virtio_dev_tx_queue_setup(struct rte_eth_dev *dev,
> > >  	}
> > >  
> > >  #ifdef RTE_MACHINE_CPUFLAG_SSSE3
> > > +	struct virtio_hw *hw = dev->data->dev_private;
> > 
> > I'd suggest to move above declaration to ...
> > 
> > >  	/* Use simple rx/tx func if single segment and no offloads */
> > >  	if ((tx_conf->txq_flags & VIRTIO_SIMPLE_FLAGS) == VIRTIO_SIMPLE_FLAGS &&
> > >  	     !vtpci_with_feature(hw, VIRTIO_NET_F_MRG_RXBUF)) {
> > 
> > here: we should try to avoid declaring vars in the middle of a code block.
> 
> Next patch in this series, moving all rxtx handler selection code to
> separate function(virtio_update_rxtx_handler()) where declaration comes
> as first line in the function.i.e the comment is taken care of in the
> series.

Yes, I saw that. But in principle, each patch is atomic: it's not a
good idea/practice to introduce issues in path A and then fix it in
path B.

	--yliu
  
Jerin Jacob July 4, 2016, 9:07 a.m. UTC | #4
On Mon, Jul 04, 2016 at 04:42:32PM +0800, Yuanhan Liu wrote:
> On Mon, Jul 04, 2016 at 02:06:27PM +0530, Jerin Jacob wrote:
> > On Mon, Jul 04, 2016 at 03:36:48PM +0800, Yuanhan Liu wrote:
> > > On Fri, Jul 01, 2016 at 04:46:36PM +0530, Jerin Jacob wrote:
> > > > @@ -494,9 +486,6 @@ virtio_dev_tx_queue_setup(struct rte_eth_dev *dev,
> > > >  {
> > > >  	uint8_t vtpci_queue_idx = 2 * queue_idx + VTNET_SQ_TQ_QUEUE_IDX;
> > > >  
> > > > -#ifdef RTE_MACHINE_CPUFLAG_SSSE3
> > > > -	struct virtio_hw *hw = dev->data->dev_private;
> > > > -#endif
> > > >  	struct virtnet_tx *txvq;
> > > >  	struct virtqueue *vq;
> > > >  	uint16_t tx_free_thresh;
> > > > @@ -511,13 +500,14 @@ virtio_dev_tx_queue_setup(struct rte_eth_dev *dev,
> > > >  	}
> > > >  
> > > >  #ifdef RTE_MACHINE_CPUFLAG_SSSE3
> > > > +	struct virtio_hw *hw = dev->data->dev_private;
> > > 
> > > I'd suggest to move above declaration to ...
> > > 
> > > >  	/* Use simple rx/tx func if single segment and no offloads */
> > > >  	if ((tx_conf->txq_flags & VIRTIO_SIMPLE_FLAGS) == VIRTIO_SIMPLE_FLAGS &&
> > > >  	     !vtpci_with_feature(hw, VIRTIO_NET_F_MRG_RXBUF)) {
> > > 
> > > here: we should try to avoid declaring vars in the middle of a code block.
> > 
> > Next patch in this series, moving all rxtx handler selection code to
> > separate function(virtio_update_rxtx_handler()) where declaration comes
> > as first line in the function.i.e the comment is taken care of in the
> > series.
> 
> Yes, I saw that. But in principle, each patch is atomic: it's not a
> good idea/practice to introduce issues in path A and then fix it in
> path B.

In my view it was not an issue as I was removing all possible
conditional compilation flag. If I were to move the declaration to top
then another conditional compilation RTE_MACHINE_CPUFLAG_SSSE3
flag I need to add around declaring the variable.

Hope this justifies the reason. If you are not convinced then let me know,
if will add the change in next revision.

Jerin

> 
> 	--yliu
  
Yuanhan Liu July 4, 2016, 11:02 a.m. UTC | #5
On Mon, Jul 04, 2016 at 02:37:55PM +0530, Jerin Jacob wrote:
> On Mon, Jul 04, 2016 at 04:42:32PM +0800, Yuanhan Liu wrote:
> > On Mon, Jul 04, 2016 at 02:06:27PM +0530, Jerin Jacob wrote:
> > > On Mon, Jul 04, 2016 at 03:36:48PM +0800, Yuanhan Liu wrote:
> > > > On Fri, Jul 01, 2016 at 04:46:36PM +0530, Jerin Jacob wrote:
> > > > > @@ -494,9 +486,6 @@ virtio_dev_tx_queue_setup(struct rte_eth_dev *dev,
> > > > >  {
> > > > >  	uint8_t vtpci_queue_idx = 2 * queue_idx + VTNET_SQ_TQ_QUEUE_IDX;
> > > > >  
> > > > > -#ifdef RTE_MACHINE_CPUFLAG_SSSE3
> > > > > -	struct virtio_hw *hw = dev->data->dev_private;
> > > > > -#endif
> > > > >  	struct virtnet_tx *txvq;
> > > > >  	struct virtqueue *vq;
> > > > >  	uint16_t tx_free_thresh;
> > > > > @@ -511,13 +500,14 @@ virtio_dev_tx_queue_setup(struct rte_eth_dev *dev,
> > > > >  	}
> > > > >  
> > > > >  #ifdef RTE_MACHINE_CPUFLAG_SSSE3
> > > > > +	struct virtio_hw *hw = dev->data->dev_private;
> > > > 
> > > > I'd suggest to move above declaration to ...
> > > > 
> > > > >  	/* Use simple rx/tx func if single segment and no offloads */
> > > > >  	if ((tx_conf->txq_flags & VIRTIO_SIMPLE_FLAGS) == VIRTIO_SIMPLE_FLAGS &&
> > > > >  	     !vtpci_with_feature(hw, VIRTIO_NET_F_MRG_RXBUF)) {
> > > > 
> > > > here: we should try to avoid declaring vars in the middle of a code block.
> > > 
> > > Next patch in this series, moving all rxtx handler selection code to
> > > separate function(virtio_update_rxtx_handler()) where declaration comes
> > > as first line in the function.i.e the comment is taken care of in the
> > > series.
> > 
> > Yes, I saw that. But in principle, each patch is atomic: it's not a
> > good idea/practice to introduce issues in path A and then fix it in
> > path B.
> 
> In my view it was not an issue as I was removing all possible
> conditional compilation flag. If I were to move the declaration to top
> then another conditional compilation RTE_MACHINE_CPUFLAG_SSSE3
> flag I need to add around declaring the variable.

Nope, I was suggesting to move it inside the "if" block. So, this
is actually consistent with what you are trying to do. Besides, it
removes an declaration in the middle.

	--yliu

> Hope this justifies the reason. If you are not convinced then let me know,
> if will add the change in next revision.
> 
> Jerin
> 
> > 
> > 	--yliu
  
Jerin Jacob July 4, 2016, 12:15 p.m. UTC | #6
On Mon, Jul 04, 2016 at 07:02:25PM +0800, Yuanhan Liu wrote:
> On Mon, Jul 04, 2016 at 02:37:55PM +0530, Jerin Jacob wrote:
> > On Mon, Jul 04, 2016 at 04:42:32PM +0800, Yuanhan Liu wrote:
> > > On Mon, Jul 04, 2016 at 02:06:27PM +0530, Jerin Jacob wrote:
> > > > On Mon, Jul 04, 2016 at 03:36:48PM +0800, Yuanhan Liu wrote:
> > > > > On Fri, Jul 01, 2016 at 04:46:36PM +0530, Jerin Jacob wrote:
> > > > > > @@ -494,9 +486,6 @@ virtio_dev_tx_queue_setup(struct rte_eth_dev *dev,
> > > > > >  {
> > > > > >  	uint8_t vtpci_queue_idx = 2 * queue_idx + VTNET_SQ_TQ_QUEUE_IDX;
> > > > > >  
> > > > > > -#ifdef RTE_MACHINE_CPUFLAG_SSSE3
> > > > > > -	struct virtio_hw *hw = dev->data->dev_private;
> > > > > > -#endif
> > > > > >  	struct virtnet_tx *txvq;
> > > > > >  	struct virtqueue *vq;
> > > > > >  	uint16_t tx_free_thresh;
> > > > > > @@ -511,13 +500,14 @@ virtio_dev_tx_queue_setup(struct rte_eth_dev *dev,
> > > > > >  	}
> > > > > >  
> > > > > >  #ifdef RTE_MACHINE_CPUFLAG_SSSE3
> > > > > > +	struct virtio_hw *hw = dev->data->dev_private;
> > > > > 
> > > > > I'd suggest to move above declaration to ...
> > > > > 
> > > > > >  	/* Use simple rx/tx func if single segment and no offloads */
> > > > > >  	if ((tx_conf->txq_flags & VIRTIO_SIMPLE_FLAGS) == VIRTIO_SIMPLE_FLAGS &&
> > > > > >  	     !vtpci_with_feature(hw, VIRTIO_NET_F_MRG_RXBUF)) {
> > > > > 
> > > > > here: we should try to avoid declaring vars in the middle of a code block.
> > > > 
> > > > Next patch in this series, moving all rxtx handler selection code to
> > > > separate function(virtio_update_rxtx_handler()) where declaration comes
> > > > as first line in the function.i.e the comment is taken care of in the
> > > > series.
> > > 
> > > Yes, I saw that. But in principle, each patch is atomic: it's not a
> > > good idea/practice to introduce issues in path A and then fix it in
> > > path B.
> > 
> > In my view it was not an issue as I was removing all possible
> > conditional compilation flag. If I were to move the declaration to top
> > then another conditional compilation RTE_MACHINE_CPUFLAG_SSSE3
> > flag I need to add around declaring the variable.
> 
> Nope, I was suggesting to move it inside the "if" block. So, this
> is actually consistent with what you are trying to do. Besides, it
> removes an declaration in the middle.

Just to get the clarity on "moving inside the 'if' block"

Are you suggesting to have like below?

 #ifdef RTE_MACHINE_CPUFLAG_SSSE3
+       struct virtio_hw *hw;
        /* Use simple rx/tx func if single segment and no offloads */
        if ((tx_conf->txq_flags & VIRTIO_SIMPLE_FLAGS) ==
VIRTIO_SIMPLE_FLAGS &&
             !vtpci_with_feature(hw, VIRTIO_NET_F_MRG_RXBUF)) {
                PMD_INIT_LOG(INFO, "Using simple rx/tx path");
                dev->tx_pkt_burst = virtio_xmit_pkts_simple;
                dev->rx_pkt_burst = virtio_recv_pkts_vec;
-               use_simple_rxtx = 1;
+		hw = dev->data->dev_private;
+               hw->use_simple_rxtx = 1;
        }
 #endif


Instead of following scheme in existing patch,

 #ifdef RTE_MACHINE_CPUFLAG_SSSE3
+       struct virtio_hw *hw = dev->data->dev_private;
        /* Use simple rx/tx func if single segment and no offloads */
        if ((tx_conf->txq_flags & VIRTIO_SIMPLE_FLAGS) ==
VIRTIO_SIMPLE_FLAGS &&
             !vtpci_with_feature(hw, VIRTIO_NET_F_MRG_RXBUF)) {
                PMD_INIT_LOG(INFO, "Using simple rx/tx path");
                dev->tx_pkt_burst = virtio_xmit_pkts_simple;
                dev->rx_pkt_burst = virtio_recv_pkts_vec;
-               use_simple_rxtx = 1;
+               hw->use_simple_rxtx = 1;
        }
 #endif


The former case will have issue as "hw" been used in "if" with vtpci_with_feature.

OR

if you meant just floating "struct virtio_hw *hw" without RTE_MACHINE_CPUFLAG_SSSE3
then it comes error on non x86 as unused "hw" variable.

If you meant something else then let me know?

> 
> 	--yliu
> 
> > Hope this justifies the reason. If you are not convinced then let me know,
> > if will add the change in next revision.
> > 
> > Jerin
> > 
> > > 
> > > 	--yliu
  
Yuanhan Liu July 4, 2016, 12:26 p.m. UTC | #7
On Mon, Jul 04, 2016 at 05:45:57PM +0530, Jerin Jacob wrote:
> On Mon, Jul 04, 2016 at 07:02:25PM +0800, Yuanhan Liu wrote:
> > On Mon, Jul 04, 2016 at 02:37:55PM +0530, Jerin Jacob wrote:
> > > On Mon, Jul 04, 2016 at 04:42:32PM +0800, Yuanhan Liu wrote:
> > > > On Mon, Jul 04, 2016 at 02:06:27PM +0530, Jerin Jacob wrote:
> > > > > On Mon, Jul 04, 2016 at 03:36:48PM +0800, Yuanhan Liu wrote:
> > > > > > On Fri, Jul 01, 2016 at 04:46:36PM +0530, Jerin Jacob wrote:
> > > > > > > @@ -494,9 +486,6 @@ virtio_dev_tx_queue_setup(struct rte_eth_dev *dev,
> > > > > > >  {
> > > > > > >  	uint8_t vtpci_queue_idx = 2 * queue_idx + VTNET_SQ_TQ_QUEUE_IDX;
> > > > > > >  
> > > > > > > -#ifdef RTE_MACHINE_CPUFLAG_SSSE3
> > > > > > > -	struct virtio_hw *hw = dev->data->dev_private;
> > > > > > > -#endif
> > > > > > >  	struct virtnet_tx *txvq;
> > > > > > >  	struct virtqueue *vq;
> > > > > > >  	uint16_t tx_free_thresh;
> > > > > > > @@ -511,13 +500,14 @@ virtio_dev_tx_queue_setup(struct rte_eth_dev *dev,
> > > > > > >  	}
> > > > > > >  
> > > > > > >  #ifdef RTE_MACHINE_CPUFLAG_SSSE3
> > > > > > > +	struct virtio_hw *hw = dev->data->dev_private;
> > > > > > 
> > > > > > I'd suggest to move above declaration to ...
> > > > > > 
> > > > > > >  	/* Use simple rx/tx func if single segment and no offloads */
> > > > > > >  	if ((tx_conf->txq_flags & VIRTIO_SIMPLE_FLAGS) == VIRTIO_SIMPLE_FLAGS &&
> > > > > > >  	     !vtpci_with_feature(hw, VIRTIO_NET_F_MRG_RXBUF)) {
> > > > > > 
> > > > > > here: we should try to avoid declaring vars in the middle of a code block.
> > > > > 
> > > > > Next patch in this series, moving all rxtx handler selection code to
> > > > > separate function(virtio_update_rxtx_handler()) where declaration comes
> > > > > as first line in the function.i.e the comment is taken care of in the
> > > > > series.
> > > > 
> > > > Yes, I saw that. But in principle, each patch is atomic: it's not a
> > > > good idea/practice to introduce issues in path A and then fix it in
> > > > path B.
> > > 
> > > In my view it was not an issue as I was removing all possible
> > > conditional compilation flag. If I were to move the declaration to top
> > > then another conditional compilation RTE_MACHINE_CPUFLAG_SSSE3
> > > flag I need to add around declaring the variable.
> > 
> > Nope, I was suggesting to move it inside the "if" block. So, this
> > is actually consistent with what you are trying to do. Besides, it
> > removes an declaration in the middle.
> 
> Just to get the clarity on "moving inside the 'if' block"
> 
> Are you suggesting to have like below?
> 
>  #ifdef RTE_MACHINE_CPUFLAG_SSSE3
> +       struct virtio_hw *hw;
>         /* Use simple rx/tx func if single segment and no offloads */
>         if ((tx_conf->txq_flags & VIRTIO_SIMPLE_FLAGS) ==
> VIRTIO_SIMPLE_FLAGS &&
>              !vtpci_with_feature(hw, VIRTIO_NET_F_MRG_RXBUF)) {
>                 PMD_INIT_LOG(INFO, "Using simple rx/tx path");
>                 dev->tx_pkt_burst = virtio_xmit_pkts_simple;
>                 dev->rx_pkt_burst = virtio_recv_pkts_vec;
> -               use_simple_rxtx = 1;
> +		hw = dev->data->dev_private;
> +               hw->use_simple_rxtx = 1;
>         }
>  #endif
> 
> 
> Instead of following scheme in existing patch,
> 
>  #ifdef RTE_MACHINE_CPUFLAG_SSSE3
> +       struct virtio_hw *hw = dev->data->dev_private;
>         /* Use simple rx/tx func if single segment and no offloads */
>         if ((tx_conf->txq_flags & VIRTIO_SIMPLE_FLAGS) ==
> VIRTIO_SIMPLE_FLAGS &&
>              !vtpci_with_feature(hw, VIRTIO_NET_F_MRG_RXBUF)) {
>                 PMD_INIT_LOG(INFO, "Using simple rx/tx path");
>                 dev->tx_pkt_burst = virtio_xmit_pkts_simple;
>                 dev->rx_pkt_burst = virtio_recv_pkts_vec;
> -               use_simple_rxtx = 1;
> +               hw->use_simple_rxtx = 1;
>         }
>  #endif
> 
> 
> The former case will have issue as "hw" been used in "if" with vtpci_with_feature.

Oh, my bad. I overlooked it. Sorry for that!

> OR
> 
> if you meant just floating "struct virtio_hw *hw" without RTE_MACHINE_CPUFLAG_SSSE3
> then it comes error on non x86 as unused "hw" variable.
> 
> If you meant something else then let me know?

I then prefer to keep the "#ifdef .. #endif" on top then. It will stop
us from offending a minor rule, while you can remove the ugly "#ifdef"
block in the next patch.

Works to you?

	--yliu
  
Jerin Jacob July 4, 2016, 12:50 p.m. UTC | #8
On Mon, Jul 04, 2016 at 08:26:30PM +0800, Yuanhan Liu wrote:
> On Mon, Jul 04, 2016 at 05:45:57PM +0530, Jerin Jacob wrote:
> > On Mon, Jul 04, 2016 at 07:02:25PM +0800, Yuanhan Liu wrote:
> > > On Mon, Jul 04, 2016 at 02:37:55PM +0530, Jerin Jacob wrote:
> > > > On Mon, Jul 04, 2016 at 04:42:32PM +0800, Yuanhan Liu wrote:
> > > > > On Mon, Jul 04, 2016 at 02:06:27PM +0530, Jerin Jacob wrote:
> > > > > > On Mon, Jul 04, 2016 at 03:36:48PM +0800, Yuanhan Liu wrote:
> > > > > > > On Fri, Jul 01, 2016 at 04:46:36PM +0530, Jerin Jacob wrote:
> > > > > > > > @@ -494,9 +486,6 @@ virtio_dev_tx_queue_setup(struct rte_eth_dev *dev,
> > > > > > > >  {
> > > > > > > >  	uint8_t vtpci_queue_idx = 2 * queue_idx + VTNET_SQ_TQ_QUEUE_IDX;
> > > > > > > >  
> > > > > > > > -#ifdef RTE_MACHINE_CPUFLAG_SSSE3
> > > > > > > > -	struct virtio_hw *hw = dev->data->dev_private;
> > > > > > > > -#endif
> > > > > > > >  	struct virtnet_tx *txvq;
> > > > > > > >  	struct virtqueue *vq;
> > > > > > > >  	uint16_t tx_free_thresh;
> > > > > > > > @@ -511,13 +500,14 @@ virtio_dev_tx_queue_setup(struct rte_eth_dev *dev,
> > > > > > > >  	}
> > > > > > > >  
> > > > > > > >  #ifdef RTE_MACHINE_CPUFLAG_SSSE3
> > > > > > > > +	struct virtio_hw *hw = dev->data->dev_private;
> > > > > > > 
> > > > > > > I'd suggest to move above declaration to ...
> > > > > > > 
> > > > > > > >  	/* Use simple rx/tx func if single segment and no offloads */
> > > > > > > >  	if ((tx_conf->txq_flags & VIRTIO_SIMPLE_FLAGS) == VIRTIO_SIMPLE_FLAGS &&
> > > > > > > >  	     !vtpci_with_feature(hw, VIRTIO_NET_F_MRG_RXBUF)) {
> > > > > > > 
> > > > > > > here: we should try to avoid declaring vars in the middle of a code block.
> > > > > > 
> > > > > > Next patch in this series, moving all rxtx handler selection code to
> > > > > > separate function(virtio_update_rxtx_handler()) where declaration comes
> > > > > > as first line in the function.i.e the comment is taken care of in the
> > > > > > series.
> > > > > 
> > > > > Yes, I saw that. But in principle, each patch is atomic: it's not a
> > > > > good idea/practice to introduce issues in path A and then fix it in
> > > > > path B.
> > > > 
> > > > In my view it was not an issue as I was removing all possible
> > > > conditional compilation flag. If I were to move the declaration to top
> > > > then another conditional compilation RTE_MACHINE_CPUFLAG_SSSE3
> > > > flag I need to add around declaring the variable.
> > > 
> > > Nope, I was suggesting to move it inside the "if" block. So, this
> > > is actually consistent with what you are trying to do. Besides, it
> > > removes an declaration in the middle.
> > 
> > Just to get the clarity on "moving inside the 'if' block"
> > 
> > Are you suggesting to have like below?
> > 
> >  #ifdef RTE_MACHINE_CPUFLAG_SSSE3
> > +       struct virtio_hw *hw;
> >         /* Use simple rx/tx func if single segment and no offloads */
> >         if ((tx_conf->txq_flags & VIRTIO_SIMPLE_FLAGS) ==
> > VIRTIO_SIMPLE_FLAGS &&
> >              !vtpci_with_feature(hw, VIRTIO_NET_F_MRG_RXBUF)) {
> >                 PMD_INIT_LOG(INFO, "Using simple rx/tx path");
> >                 dev->tx_pkt_burst = virtio_xmit_pkts_simple;
> >                 dev->rx_pkt_burst = virtio_recv_pkts_vec;
> > -               use_simple_rxtx = 1;
> > +		hw = dev->data->dev_private;
> > +               hw->use_simple_rxtx = 1;
> >         }
> >  #endif
> > 
> > 
> > Instead of following scheme in existing patch,
> > 
> >  #ifdef RTE_MACHINE_CPUFLAG_SSSE3
> > +       struct virtio_hw *hw = dev->data->dev_private;
> >         /* Use simple rx/tx func if single segment and no offloads */
> >         if ((tx_conf->txq_flags & VIRTIO_SIMPLE_FLAGS) ==
> > VIRTIO_SIMPLE_FLAGS &&
> >              !vtpci_with_feature(hw, VIRTIO_NET_F_MRG_RXBUF)) {
> >                 PMD_INIT_LOG(INFO, "Using simple rx/tx path");
> >                 dev->tx_pkt_burst = virtio_xmit_pkts_simple;
> >                 dev->rx_pkt_burst = virtio_recv_pkts_vec;
> > -               use_simple_rxtx = 1;
> > +               hw->use_simple_rxtx = 1;
> >         }
> >  #endif
> > 
> > 
> > The former case will have issue as "hw" been used in "if" with vtpci_with_feature.
> 
> Oh, my bad. I overlooked it. Sorry for that!
> 
> > OR
> > 
> > if you meant just floating "struct virtio_hw *hw" without RTE_MACHINE_CPUFLAG_SSSE3
> > then it comes error on non x86 as unused "hw" variable.
> > 
> > If you meant something else then let me know?
> 
> I then prefer to keep the "#ifdef .. #endif" on top then. It will stop
> us from offending a minor rule, while you can remove the ugly "#ifdef"
> block in the next patch.
> 
> Works to you?

OK. As you wish :-)

> 
> 	--yliu
  
Yuanhan Liu July 4, 2016, 12:57 p.m. UTC | #9
On Mon, Jul 04, 2016 at 06:20:42PM +0530, Jerin Jacob wrote:
> > > The former case will have issue as "hw" been used in "if" with vtpci_with_feature.
> > 
> > Oh, my bad. I overlooked it. Sorry for that!
> > 
> > > OR
> > > 
> > > if you meant just floating "struct virtio_hw *hw" without RTE_MACHINE_CPUFLAG_SSSE3
> > > then it comes error on non x86 as unused "hw" variable.
> > > 
> > > If you meant something else then let me know?
> > 
> > I then prefer to keep the "#ifdef .. #endif" on top then. It will stop
> > us from offending a minor rule, while you can remove the ugly "#ifdef"
> > block in the next patch.
> > 
> > Works to you?
> 
> OK. As you wish :-)

Thank you!

	--yliu
  

Patch

diff --git a/drivers/net/virtio/Makefile b/drivers/net/virtio/Makefile
index 3020b68..b9b0d8d 100644
--- a/drivers/net/virtio/Makefile
+++ b/drivers/net/virtio/Makefile
@@ -50,10 +50,7 @@  SRCS-$(CONFIG_RTE_LIBRTE_VIRTIO_PMD) += virtqueue.c
 SRCS-$(CONFIG_RTE_LIBRTE_VIRTIO_PMD) += virtio_pci.c
 SRCS-$(CONFIG_RTE_LIBRTE_VIRTIO_PMD) += virtio_rxtx.c
 SRCS-$(CONFIG_RTE_LIBRTE_VIRTIO_PMD) += virtio_ethdev.c
-
-ifeq ($(findstring RTE_MACHINE_CPUFLAG_SSSE3,$(CFLAGS)),RTE_MACHINE_CPUFLAG_SSSE3)
 SRCS-$(CONFIG_RTE_LIBRTE_VIRTIO_PMD) += virtio_rxtx_simple.c
-endif
 
 ifeq ($(CONFIG_RTE_VIRTIO_USER),y)
 SRCS-$(CONFIG_RTE_LIBRTE_VIRTIO_PMD) += virtio_user/vhost_user.c
diff --git a/drivers/net/virtio/virtio_pci.h b/drivers/net/virtio/virtio_pci.h
index dd7693f..b8295a7 100644
--- a/drivers/net/virtio/virtio_pci.h
+++ b/drivers/net/virtio/virtio_pci.h
@@ -253,6 +253,7 @@  struct virtio_hw {
 	uint8_t	    use_msix;
 	uint8_t     started;
 	uint8_t     modern;
+	uint8_t     use_simple_rxtx;
 	uint8_t     mac_addr[ETHER_ADDR_LEN];
 	uint32_t    notify_off_multiplier;
 	uint8_t     *isr;
diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
index a27208e..63b53f7 100644
--- a/drivers/net/virtio/virtio_rxtx.c
+++ b/drivers/net/virtio/virtio_rxtx.c
@@ -67,10 +67,6 @@ 
 #define VIRTIO_SIMPLE_FLAGS ((uint32_t)ETH_TXQ_FLAGS_NOMULTSEGS | \
 	ETH_TXQ_FLAGS_NOOFFLOADS)
 
-#ifdef RTE_MACHINE_CPUFLAG_SSSE3
-static int use_simple_rxtx;
-#endif
-
 static void
 vq_ring_free_chain(struct virtqueue *vq, uint16_t desc_idx)
 {
@@ -333,6 +329,7 @@  virtio_dev_rxtx_start(struct rte_eth_dev *dev)
 	 */
 	uint16_t i;
 	uint16_t desc_idx;
+	struct virtio_hw *hw = dev->data->dev_private;
 
 	PMD_INIT_FUNC_TRACE();
 
@@ -353,8 +350,7 @@  virtio_dev_rxtx_start(struct rte_eth_dev *dev)
 		nbufs = 0;
 		error = ENOSPC;
 
-#ifdef RTE_MACHINE_CPUFLAG_SSSE3
-		if (use_simple_rxtx) {
+		if (hw->use_simple_rxtx) {
 			for (desc_idx = 0; desc_idx < vq->vq_nentries;
 			     desc_idx++) {
 				vq->vq_ring.avail->ring[desc_idx] = desc_idx;
@@ -362,7 +358,7 @@  virtio_dev_rxtx_start(struct rte_eth_dev *dev)
 					VRING_DESC_F_WRITE;
 			}
 		}
-#endif
+
 		memset(&rxvq->fake_mbuf, 0, sizeof(rxvq->fake_mbuf));
 		for (desc_idx = 0; desc_idx < RTE_PMD_VIRTIO_RX_MAX_BURST;
 		     desc_idx++) {
@@ -378,12 +374,11 @@  virtio_dev_rxtx_start(struct rte_eth_dev *dev)
 			/******************************************
 			*         Enqueue allocated buffers        *
 			*******************************************/
-#ifdef RTE_MACHINE_CPUFLAG_SSSE3
-			if (use_simple_rxtx)
+			if (hw->use_simple_rxtx)
 				error = virtqueue_enqueue_recv_refill_simple(vq, m);
 			else
-#endif
 				error = virtqueue_enqueue_recv_refill(vq, m);
+
 			if (error) {
 				rte_pktmbuf_free(m);
 				break;
@@ -404,8 +399,7 @@  virtio_dev_rxtx_start(struct rte_eth_dev *dev)
 		struct virtqueue *vq = txvq->vq;
 
 		virtio_dev_vring_start(vq);
-#ifdef RTE_MACHINE_CPUFLAG_SSSE3
-		if (use_simple_rxtx) {
+		if (hw->use_simple_rxtx) {
 			uint16_t mid_idx  = vq->vq_nentries >> 1;
 
 			for (desc_idx = 0; desc_idx < mid_idx; desc_idx++) {
@@ -426,7 +420,7 @@  virtio_dev_rxtx_start(struct rte_eth_dev *dev)
 			     desc_idx++)
 				vq->vq_ring.avail->ring[desc_idx] = desc_idx;
 		}
-#endif
+
 		VIRTQUEUE_DUMP(vq);
 	}
 }
@@ -456,9 +450,7 @@  virtio_dev_rx_queue_setup(struct rte_eth_dev *dev,
 
 	dev->data->rx_queues[queue_idx] = rxvq;
 
-#ifdef RTE_MACHINE_CPUFLAG_SSSE3
 	virtio_rxq_vec_setup(rxvq);
-#endif
 
 	return 0;
 }
@@ -494,9 +486,6 @@  virtio_dev_tx_queue_setup(struct rte_eth_dev *dev,
 {
 	uint8_t vtpci_queue_idx = 2 * queue_idx + VTNET_SQ_TQ_QUEUE_IDX;
 
-#ifdef RTE_MACHINE_CPUFLAG_SSSE3
-	struct virtio_hw *hw = dev->data->dev_private;
-#endif
 	struct virtnet_tx *txvq;
 	struct virtqueue *vq;
 	uint16_t tx_free_thresh;
@@ -511,13 +500,14 @@  virtio_dev_tx_queue_setup(struct rte_eth_dev *dev,
 	}
 
 #ifdef RTE_MACHINE_CPUFLAG_SSSE3
+	struct virtio_hw *hw = dev->data->dev_private;
 	/* Use simple rx/tx func if single segment and no offloads */
 	if ((tx_conf->txq_flags & VIRTIO_SIMPLE_FLAGS) == VIRTIO_SIMPLE_FLAGS &&
 	     !vtpci_with_feature(hw, VIRTIO_NET_F_MRG_RXBUF)) {
 		PMD_INIT_LOG(INFO, "Using simple rx/tx path");
 		dev->tx_pkt_burst = virtio_xmit_pkts_simple;
 		dev->rx_pkt_burst = virtio_recv_pkts_vec;
-		use_simple_rxtx = 1;
+		hw->use_simple_rxtx = 1;
 	}
 #endif
 
diff --git a/drivers/net/virtio/virtio_rxtx.h b/drivers/net/virtio/virtio_rxtx.h
index 058b56a..28f82d6 100644
--- a/drivers/net/virtio/virtio_rxtx.h
+++ b/drivers/net/virtio/virtio_rxtx.h
@@ -86,10 +86,9 @@  struct virtnet_ctl {
 	const struct rte_memzone *mz;   /**< mem zone to populate RX ring. */
 };
 
-#ifdef RTE_MACHINE_CPUFLAG_SSSE3
 int virtio_rxq_vec_setup(struct virtnet_rx *rxvq);
 
 int virtqueue_enqueue_recv_refill_simple(struct virtqueue *vq,
 	struct rte_mbuf *m);
-#endif
+
 #endif /* _VIRTIO_RXTX_H_ */
diff --git a/drivers/net/virtio/virtio_rxtx_simple.c b/drivers/net/virtio/virtio_rxtx_simple.c
index 242ad90..67430da 100644
--- a/drivers/net/virtio/virtio_rxtx_simple.c
+++ b/drivers/net/virtio/virtio_rxtx_simple.c
@@ -37,8 +37,6 @@ 
 #include <string.h>
 #include <errno.h>
 
-#include <tmmintrin.h>
-
 #include <rte_cycles.h>
 #include <rte_memory.h>
 #include <rte_memzone.h>
@@ -131,6 +129,10 @@  virtio_rxq_rearm_vec(struct virtnet_rx *rxvq)
 	vq_update_avail_idx(vq);
 }
 
+#ifdef RTE_MACHINE_CPUFLAG_SSSE3
+
+#include <tmmintrin.h>
+
 /* virtio vPMD receive routine, only accept(nb_pkts >= RTE_VIRTIO_DESC_PER_LOOP)
  *
  * This routine is for non-mergeable RX, one desc for each guest buffer.
@@ -293,6 +295,8 @@  virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
 	return nb_pkts_received;
 }
 
+#endif
+
 #define VIRTIO_TX_FREE_THRESH 32
 #define VIRTIO_TX_MAX_FREE_BUF_SZ 32
 #define VIRTIO_TX_FREE_NR 32
diff --git a/drivers/net/virtio/virtio_user_ethdev.c b/drivers/net/virtio/virtio_user_ethdev.c
index 5ab2471..bef8130 100644
--- a/drivers/net/virtio/virtio_user_ethdev.c
+++ b/drivers/net/virtio/virtio_user_ethdev.c
@@ -303,6 +303,7 @@  virtio_user_eth_dev_alloc(const char *name)
 	hw->vtpci_ops = &virtio_user_ops;
 	hw->use_msix = 0;
 	hw->modern   = 0;
+	hw->use_simple_rxtx = 0;
 	hw->virtio_user_dev = dev;
 	data->dev_private = hw;
 	data->numa_node = SOCKET_ID_ANY;