[v2,2/2] net/virtio: on demand cleanup when doing in order xmit

Message ID 20190910161446.36361-2-yong.liu@intel.com
State New
Delegated to: Maxime Coquelin
Headers show
Series
  • [v2,1/2] net/virtio: update stats when in order xmit done
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Checks

Context Check Description
ci/Intel-compilation success Compilation OK
ci/checkpatch success coding style OK

Commit Message

Liu, Yong Sept. 10, 2019, 4:14 p.m.
Check whether space are enough before burst enqueue operation. If more
space is needed, will try to cleanup used descriptors for space on
demand. It can give more chances to free used descriptors, thus will
help RFC2544 performance.

Signed-off-by: Marvin Liu <yong.liu@intel.com>
---
 drivers/net/virtio/virtio_rxtx.c | 73 +++++++++++++++++++++++---------
 1 file changed, 54 insertions(+), 19 deletions(-)

Comments

Tiwei Bie Sept. 18, 2019, 2:43 a.m. | #1
On Wed, Sep 11, 2019 at 12:14:46AM +0800, Marvin Liu wrote:
> Check whether space are enough before burst enqueue operation. If more
> space is needed, will try to cleanup used descriptors for space on
> demand. It can give more chances to free used descriptors, thus will
> help RFC2544 performance.
> 
> Signed-off-by: Marvin Liu <yong.liu@intel.com>
> ---
>  drivers/net/virtio/virtio_rxtx.c | 73 +++++++++++++++++++++++---------
>  1 file changed, 54 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
> index d3ca36831..842b600c3 100644
> --- a/drivers/net/virtio/virtio_rxtx.c
> +++ b/drivers/net/virtio/virtio_rxtx.c
> @@ -2152,6 +2152,22 @@ virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
>  	return nb_tx;
>  }
>  
> +static __rte_always_inline int
> +virtio_xmit_try_cleanup_inorder(struct virtqueue *vq, uint16_t need)
> +{
> +	uint16_t nb_used, nb_clean, nb_descs;
> +	struct virtio_hw *hw = vq->hw;
> +
> +	nb_descs = vq->vq_free_cnt + need;
> +	nb_used = VIRTQUEUE_NUSED(vq);
> +	virtio_rmb(hw->weak_barriers);
> +	nb_clean = RTE_MIN(need, (int)nb_used);
> +
> +	virtio_xmit_cleanup_inorder(vq, nb_clean);
> +
> +	return (nb_descs - vq->vq_free_cnt);
> +}
> +
>  uint16_t
>  virtio_xmit_pkts_inorder(void *tx_queue,
>  			struct rte_mbuf **tx_pkts,
> @@ -2161,8 +2177,9 @@ virtio_xmit_pkts_inorder(void *tx_queue,
>  	struct virtqueue *vq = txvq->vq;
>  	struct virtio_hw *hw = vq->hw;
>  	uint16_t hdr_size = hw->vtnet_hdr_size;
> -	uint16_t nb_used, nb_avail, nb_tx = 0, nb_inorder_pkts = 0;
> +	uint16_t nb_used, nb_tx = 0, nb_inorder_pkts = 0;
>  	struct rte_mbuf *inorder_pkts[nb_pkts];
> +	int need, nb_left;
>  
>  	if (unlikely(hw->started == 0 && tx_pkts != hw->inject_pkts))
>  		return nb_tx;
> @@ -2175,17 +2192,12 @@ virtio_xmit_pkts_inorder(void *tx_queue,
>  	nb_used = VIRTQUEUE_NUSED(vq);
>  
>  	virtio_rmb(hw->weak_barriers);
> -	if (likely(nb_used > vq->vq_nentries - vq->vq_free_thresh))
> -		virtio_xmit_cleanup_inorder(vq, nb_used);
> -
> -	if (unlikely(!vq->vq_free_cnt))
> +	if (likely(nb_used > (vq->vq_nentries - vq->vq_free_thresh)))
>  		virtio_xmit_cleanup_inorder(vq, nb_used);
>  
> -	nb_avail = RTE_MIN(vq->vq_free_cnt, nb_pkts);
> -
> -	for (nb_tx = 0; nb_tx < nb_avail; nb_tx++) {
> +	for (nb_tx = 0; nb_tx < nb_pkts; nb_tx++) {
>  		struct rte_mbuf *txm = tx_pkts[nb_tx];
> -		int slots, need;
> +		int slots;
>  
>  		/* optimize ring usage */
>  		if ((vtpci_with_feature(hw, VIRTIO_F_ANY_LAYOUT) ||
> @@ -2199,11 +2211,25 @@ virtio_xmit_pkts_inorder(void *tx_queue,
>  			inorder_pkts[nb_inorder_pkts] = txm;
>  			nb_inorder_pkts++;
>  
> -			virtio_update_packet_stats(&txvq->stats, txm);
>  			continue;
>  		}
>  
>  		if (nb_inorder_pkts) {
> +			need = nb_inorder_pkts - vq->vq_free_cnt;
> +
> +			if (unlikely(need > 0)) {
> +				nb_left = virtio_xmit_try_cleanup_inorder(vq,
> +									need);

There is no need to introduce `nb_left`. Looks better
to just reuse `need`.

> +
> +				if (unlikely(nb_left > 0)) {
> +					PMD_TX_LOG(ERR,
> +						"No free tx descriptors to "
> +						"transmit");
> +					nb_inorder_pkts = vq->vq_free_cnt;

You need to handle nb_tx as well, otherwise mbufs will leak.
Or maybe just leave nb_inorder_pkts unchanged, and let the code
outside the loop handle it.


> +					break;
> +				}
> +			}
> +
>  			virtqueue_enqueue_xmit_inorder(txvq, inorder_pkts,
>  							nb_inorder_pkts);
>  			nb_inorder_pkts = 0;
> @@ -2212,15 +2238,9 @@ virtio_xmit_pkts_inorder(void *tx_queue,
>  		slots = txm->nb_segs + 1;
>  		need = slots - vq->vq_free_cnt;
>  		if (unlikely(need > 0)) {
> -			nb_used = VIRTQUEUE_NUSED(vq);
> -			virtio_rmb(hw->weak_barriers);
> -			need = RTE_MIN(need, (int)nb_used);
> -
> -			virtio_xmit_cleanup_inorder(vq, need);
> +			nb_left = virtio_xmit_try_cleanup_inorder(vq, slots);
>  
> -			need = slots - vq->vq_free_cnt;
> -
> -			if (unlikely(need > 0)) {
> +			if (unlikely(nb_left > 0)) {
>  				PMD_TX_LOG(ERR,
>  					"No free tx descriptors to transmit");
>  				break;
> @@ -2233,9 +2253,24 @@ virtio_xmit_pkts_inorder(void *tx_queue,
>  	}
>  
>  	/* Transmit all inorder packets */
> -	if (nb_inorder_pkts)
> +	if (nb_inorder_pkts) {
> +		need = nb_inorder_pkts - vq->vq_free_cnt;
> +
> +		if (unlikely(need > 0)) {
> +			nb_left = virtio_xmit_try_cleanup_inorder(vq,
> +								  need);
> +
> +			if (unlikely(nb_left > 0)) {
> +				PMD_TX_LOG(ERR,
> +					"No free tx descriptors to transmit");
> +				nb_inorder_pkts = vq->vq_free_cnt;
> +				nb_tx -= nb_left;
> +			}
> +		}
> +
>  		virtqueue_enqueue_xmit_inorder(txvq, inorder_pkts,
>  						nb_inorder_pkts);
> +	}
>  
>  	txvq->stats.packets += nb_tx;
>  
> -- 
> 2.17.1
>
Liu, Yong Sept. 18, 2019, 3:23 a.m. | #2
Thanks for comments, will update in next patch.

> -----Original Message-----
> From: Bie, Tiwei
> Sent: Wednesday, September 18, 2019 10:44 AM
> To: Liu, Yong <yong.liu@intel.com>
> Cc: maxime.coquelin@redhat.com; dev@dpdk.org
> Subject: Re: [PATCH v2 2/2] net/virtio: on demand cleanup when doing in
> order xmit
> 
> On Wed, Sep 11, 2019 at 12:14:46AM +0800, Marvin Liu wrote:
> > Check whether space are enough before burst enqueue operation. If more
> > space is needed, will try to cleanup used descriptors for space on
> > demand. It can give more chances to free used descriptors, thus will
> > help RFC2544 performance.
> >
> > Signed-off-by: Marvin Liu <yong.liu@intel.com>
> > ---
> >  drivers/net/virtio/virtio_rxtx.c | 73 +++++++++++++++++++++++---------
> >  1 file changed, 54 insertions(+), 19 deletions(-)
> >
> > diff --git a/drivers/net/virtio/virtio_rxtx.c
> b/drivers/net/virtio/virtio_rxtx.c
> > index d3ca36831..842b600c3 100644
> > --- a/drivers/net/virtio/virtio_rxtx.c
> > +++ b/drivers/net/virtio/virtio_rxtx.c
> > @@ -2152,6 +2152,22 @@ virtio_xmit_pkts(void *tx_queue, struct rte_mbuf
> **tx_pkts, uint16_t nb_pkts)
> >  	return nb_tx;
> >  }
> >
> > +static __rte_always_inline int
> > +virtio_xmit_try_cleanup_inorder(struct virtqueue *vq, uint16_t need)
> > +{
> > +	uint16_t nb_used, nb_clean, nb_descs;
> > +	struct virtio_hw *hw = vq->hw;
> > +
> > +	nb_descs = vq->vq_free_cnt + need;
> > +	nb_used = VIRTQUEUE_NUSED(vq);
> > +	virtio_rmb(hw->weak_barriers);
> > +	nb_clean = RTE_MIN(need, (int)nb_used);
> > +
> > +	virtio_xmit_cleanup_inorder(vq, nb_clean);
> > +
> > +	return (nb_descs - vq->vq_free_cnt);
> > +}
> > +
> >  uint16_t
> >  virtio_xmit_pkts_inorder(void *tx_queue,
> >  			struct rte_mbuf **tx_pkts,
> > @@ -2161,8 +2177,9 @@ virtio_xmit_pkts_inorder(void *tx_queue,
> >  	struct virtqueue *vq = txvq->vq;
> >  	struct virtio_hw *hw = vq->hw;
> >  	uint16_t hdr_size = hw->vtnet_hdr_size;
> > -	uint16_t nb_used, nb_avail, nb_tx = 0, nb_inorder_pkts = 0;
> > +	uint16_t nb_used, nb_tx = 0, nb_inorder_pkts = 0;
> >  	struct rte_mbuf *inorder_pkts[nb_pkts];
> > +	int need, nb_left;
> >
> >  	if (unlikely(hw->started == 0 && tx_pkts != hw->inject_pkts))
> >  		return nb_tx;
> > @@ -2175,17 +2192,12 @@ virtio_xmit_pkts_inorder(void *tx_queue,
> >  	nb_used = VIRTQUEUE_NUSED(vq);
> >
> >  	virtio_rmb(hw->weak_barriers);
> > -	if (likely(nb_used > vq->vq_nentries - vq->vq_free_thresh))
> > -		virtio_xmit_cleanup_inorder(vq, nb_used);
> > -
> > -	if (unlikely(!vq->vq_free_cnt))
> > +	if (likely(nb_used > (vq->vq_nentries - vq->vq_free_thresh)))
> >  		virtio_xmit_cleanup_inorder(vq, nb_used);
> >
> > -	nb_avail = RTE_MIN(vq->vq_free_cnt, nb_pkts);
> > -
> > -	for (nb_tx = 0; nb_tx < nb_avail; nb_tx++) {
> > +	for (nb_tx = 0; nb_tx < nb_pkts; nb_tx++) {
> >  		struct rte_mbuf *txm = tx_pkts[nb_tx];
> > -		int slots, need;
> > +		int slots;
> >
> >  		/* optimize ring usage */
> >  		if ((vtpci_with_feature(hw, VIRTIO_F_ANY_LAYOUT) ||
> > @@ -2199,11 +2211,25 @@ virtio_xmit_pkts_inorder(void *tx_queue,
> >  			inorder_pkts[nb_inorder_pkts] = txm;
> >  			nb_inorder_pkts++;
> >
> > -			virtio_update_packet_stats(&txvq->stats, txm);
> >  			continue;
> >  		}
> >
> >  		if (nb_inorder_pkts) {
> > +			need = nb_inorder_pkts - vq->vq_free_cnt;
> > +
> > +			if (unlikely(need > 0)) {
> > +				nb_left = virtio_xmit_try_cleanup_inorder(vq,
> > +									need);
> 
> There is no need to introduce `nb_left`. Looks better
> to just reuse `need`.
> 
> > +
> > +				if (unlikely(nb_left > 0)) {
> > +					PMD_TX_LOG(ERR,
> > +						"No free tx descriptors to "
> > +						"transmit");
> > +					nb_inorder_pkts = vq->vq_free_cnt;
> 
> You need to handle nb_tx as well, otherwise mbufs will leak.
> Or maybe just leave nb_inorder_pkts unchanged, and let the code
> outside the loop handle it.
> 
> 
> > +					break;
> > +				}
> > +			}
> > +
> >  			virtqueue_enqueue_xmit_inorder(txvq, inorder_pkts,
> >  							nb_inorder_pkts);
> >  			nb_inorder_pkts = 0;
> > @@ -2212,15 +2238,9 @@ virtio_xmit_pkts_inorder(void *tx_queue,
> >  		slots = txm->nb_segs + 1;
> >  		need = slots - vq->vq_free_cnt;
> >  		if (unlikely(need > 0)) {
> > -			nb_used = VIRTQUEUE_NUSED(vq);
> > -			virtio_rmb(hw->weak_barriers);
> > -			need = RTE_MIN(need, (int)nb_used);
> > -
> > -			virtio_xmit_cleanup_inorder(vq, need);
> > +			nb_left = virtio_xmit_try_cleanup_inorder(vq, slots);
> >
> > -			need = slots - vq->vq_free_cnt;
> > -
> > -			if (unlikely(need > 0)) {
> > +			if (unlikely(nb_left > 0)) {
> >  				PMD_TX_LOG(ERR,
> >  					"No free tx descriptors to transmit");
> >  				break;
> > @@ -2233,9 +2253,24 @@ virtio_xmit_pkts_inorder(void *tx_queue,
> >  	}
> >
> >  	/* Transmit all inorder packets */
> > -	if (nb_inorder_pkts)
> > +	if (nb_inorder_pkts) {
> > +		need = nb_inorder_pkts - vq->vq_free_cnt;
> > +
> > +		if (unlikely(need > 0)) {
> > +			nb_left = virtio_xmit_try_cleanup_inorder(vq,
> > +								  need);
> > +
> > +			if (unlikely(nb_left > 0)) {
> > +				PMD_TX_LOG(ERR,
> > +					"No free tx descriptors to transmit");
> > +				nb_inorder_pkts = vq->vq_free_cnt;
> > +				nb_tx -= nb_left;
> > +			}
> > +		}
> > +
> >  		virtqueue_enqueue_xmit_inorder(txvq, inorder_pkts,
> >  						nb_inorder_pkts);
> > +	}
> >
> >  	txvq->stats.packets += nb_tx;
> >
> > --
> > 2.17.1
> >

Patch

diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
index d3ca36831..842b600c3 100644
--- a/drivers/net/virtio/virtio_rxtx.c
+++ b/drivers/net/virtio/virtio_rxtx.c
@@ -2152,6 +2152,22 @@  virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
 	return nb_tx;
 }
 
+static __rte_always_inline int
+virtio_xmit_try_cleanup_inorder(struct virtqueue *vq, uint16_t need)
+{
+	uint16_t nb_used, nb_clean, nb_descs;
+	struct virtio_hw *hw = vq->hw;
+
+	nb_descs = vq->vq_free_cnt + need;
+	nb_used = VIRTQUEUE_NUSED(vq);
+	virtio_rmb(hw->weak_barriers);
+	nb_clean = RTE_MIN(need, (int)nb_used);
+
+	virtio_xmit_cleanup_inorder(vq, nb_clean);
+
+	return (nb_descs - vq->vq_free_cnt);
+}
+
 uint16_t
 virtio_xmit_pkts_inorder(void *tx_queue,
 			struct rte_mbuf **tx_pkts,
@@ -2161,8 +2177,9 @@  virtio_xmit_pkts_inorder(void *tx_queue,
 	struct virtqueue *vq = txvq->vq;
 	struct virtio_hw *hw = vq->hw;
 	uint16_t hdr_size = hw->vtnet_hdr_size;
-	uint16_t nb_used, nb_avail, nb_tx = 0, nb_inorder_pkts = 0;
+	uint16_t nb_used, nb_tx = 0, nb_inorder_pkts = 0;
 	struct rte_mbuf *inorder_pkts[nb_pkts];
+	int need, nb_left;
 
 	if (unlikely(hw->started == 0 && tx_pkts != hw->inject_pkts))
 		return nb_tx;
@@ -2175,17 +2192,12 @@  virtio_xmit_pkts_inorder(void *tx_queue,
 	nb_used = VIRTQUEUE_NUSED(vq);
 
 	virtio_rmb(hw->weak_barriers);
-	if (likely(nb_used > vq->vq_nentries - vq->vq_free_thresh))
-		virtio_xmit_cleanup_inorder(vq, nb_used);
-
-	if (unlikely(!vq->vq_free_cnt))
+	if (likely(nb_used > (vq->vq_nentries - vq->vq_free_thresh)))
 		virtio_xmit_cleanup_inorder(vq, nb_used);
 
-	nb_avail = RTE_MIN(vq->vq_free_cnt, nb_pkts);
-
-	for (nb_tx = 0; nb_tx < nb_avail; nb_tx++) {
+	for (nb_tx = 0; nb_tx < nb_pkts; nb_tx++) {
 		struct rte_mbuf *txm = tx_pkts[nb_tx];
-		int slots, need;
+		int slots;
 
 		/* optimize ring usage */
 		if ((vtpci_with_feature(hw, VIRTIO_F_ANY_LAYOUT) ||
@@ -2199,11 +2211,25 @@  virtio_xmit_pkts_inorder(void *tx_queue,
 			inorder_pkts[nb_inorder_pkts] = txm;
 			nb_inorder_pkts++;
 
-			virtio_update_packet_stats(&txvq->stats, txm);
 			continue;
 		}
 
 		if (nb_inorder_pkts) {
+			need = nb_inorder_pkts - vq->vq_free_cnt;
+
+			if (unlikely(need > 0)) {
+				nb_left = virtio_xmit_try_cleanup_inorder(vq,
+									need);
+
+				if (unlikely(nb_left > 0)) {
+					PMD_TX_LOG(ERR,
+						"No free tx descriptors to "
+						"transmit");
+					nb_inorder_pkts = vq->vq_free_cnt;
+					break;
+				}
+			}
+
 			virtqueue_enqueue_xmit_inorder(txvq, inorder_pkts,
 							nb_inorder_pkts);
 			nb_inorder_pkts = 0;
@@ -2212,15 +2238,9 @@  virtio_xmit_pkts_inorder(void *tx_queue,
 		slots = txm->nb_segs + 1;
 		need = slots - vq->vq_free_cnt;
 		if (unlikely(need > 0)) {
-			nb_used = VIRTQUEUE_NUSED(vq);
-			virtio_rmb(hw->weak_barriers);
-			need = RTE_MIN(need, (int)nb_used);
-
-			virtio_xmit_cleanup_inorder(vq, need);
+			nb_left = virtio_xmit_try_cleanup_inorder(vq, slots);
 
-			need = slots - vq->vq_free_cnt;
-
-			if (unlikely(need > 0)) {
+			if (unlikely(nb_left > 0)) {
 				PMD_TX_LOG(ERR,
 					"No free tx descriptors to transmit");
 				break;
@@ -2233,9 +2253,24 @@  virtio_xmit_pkts_inorder(void *tx_queue,
 	}
 
 	/* Transmit all inorder packets */
-	if (nb_inorder_pkts)
+	if (nb_inorder_pkts) {
+		need = nb_inorder_pkts - vq->vq_free_cnt;
+
+		if (unlikely(need > 0)) {
+			nb_left = virtio_xmit_try_cleanup_inorder(vq,
+								  need);
+
+			if (unlikely(nb_left > 0)) {
+				PMD_TX_LOG(ERR,
+					"No free tx descriptors to transmit");
+				nb_inorder_pkts = vq->vq_free_cnt;
+				nb_tx -= nb_left;
+			}
+		}
+
 		virtqueue_enqueue_xmit_inorder(txvq, inorder_pkts,
 						nb_inorder_pkts);
+	}
 
 	txvq->stats.packets += nb_tx;