[dpdk-dev] [PATCH] net/virtio: fix vectorized Rx queue stuck

[dpdk-dev] [PATCH] net/virtio: fix vectorized Rx queue stuck

[Xueming Li]

When Rx burst size >= Rx queue size, all descriptors in used queue
consumed without rearm, the next Rx burst found no new packets and
returned directly without rearm as well.

This patch rearms available queue at once after rx_burst to avoid vq
hungry.

Fixes: fc3d66212fed ("virtio: add vector Rx")
Cc: huawei.xie@intel.com
Fixes: 2d7c37194ee4 ("net/virtio: add NEON based Rx handler")
Cc: jerin.jacob@caviumnetworks.com
Fixes: 52b5a707e6ca ("net/virtio: add Altivec Rx")
Cc: drc@linux.vnet.ibm.com
Cc: stable@dpdk.org

Signed-off-by: Xueming Li <xuemingl@nvidia.com>
---
 drivers/net/virtio/virtio_rxtx_simple_altivec.c | 12 ++++++------
 drivers/net/virtio/virtio_rxtx_simple_neon.c    | 12 ++++++------
 drivers/net/virtio/virtio_rxtx_simple_sse.c     | 12 ++++++------
 3 files changed, 18 insertions(+), 18 deletions(-)

diff --git a/drivers/net/virtio/virtio_rxtx_simple_altivec.c b/drivers/net/virtio/virtio_rxtx_simple_altivec.c
index 62e5100a48..1ffae234da 100644
--- a/drivers/net/virtio/virtio_rxtx_simple_altivec.c
+++ b/drivers/net/virtio/virtio_rxtx_simple_altivec.c
@@ -102,12 +102,6 @@ virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
 
 	rte_prefetch0(rused);
 
-	if (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
-		virtio_rxq_rearm_vec(rxvq);
-		if (unlikely(virtqueue_kick_prepare(vq)))
-			virtqueue_notify(vq);
-	}
-
 	nb_total = nb_used;
 	ref_rx_pkts = rx_pkts;
 	for (nb_pkts_received = 0;
@@ -204,5 +198,11 @@ virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
 	for (nb_used = 0; nb_used < nb_pkts_received; nb_used++)
 		virtio_update_packet_stats(&rxvq->stats, ref_rx_pkts[nb_used]);
 
+	if (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
+		virtio_rxq_rearm_vec(rxvq);
+		if (unlikely(virtqueue_kick_prepare(vq)))
+			virtqueue_notify(vq);
+	}
+
 	return nb_pkts_received;
 }
diff --git a/drivers/net/virtio/virtio_rxtx_simple_neon.c b/drivers/net/virtio/virtio_rxtx_simple_neon.c
index c8e4b13a02..341dedce41 100644
--- a/drivers/net/virtio/virtio_rxtx_simple_neon.c
+++ b/drivers/net/virtio/virtio_rxtx_simple_neon.c
@@ -100,12 +100,6 @@ virtio_recv_pkts_vec(void *rx_queue,
 
 	rte_prefetch_non_temporal(rused);
 
-	if (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
-		virtio_rxq_rearm_vec(rxvq);
-		if (unlikely(virtqueue_kick_prepare(vq)))
-			virtqueue_notify(vq);
-	}
-
 	nb_total = nb_used;
 	ref_rx_pkts = rx_pkts;
 	for (nb_pkts_received = 0;
@@ -210,5 +204,11 @@ virtio_recv_pkts_vec(void *rx_queue,
 	for (nb_used = 0; nb_used < nb_pkts_received; nb_used++)
 		virtio_update_packet_stats(&rxvq->stats, ref_rx_pkts[nb_used]);
 
+	if (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
+		virtio_rxq_rearm_vec(rxvq);
+		if (unlikely(virtqueue_kick_prepare(vq)))
+			virtqueue_notify(vq);
+	}
+
 	return nb_pkts_received;
 }
diff --git a/drivers/net/virtio/virtio_rxtx_simple_sse.c b/drivers/net/virtio/virtio_rxtx_simple_sse.c
index ff4eba33d6..2e17f9d1f2 100644
--- a/drivers/net/virtio/virtio_rxtx_simple_sse.c
+++ b/drivers/net/virtio/virtio_rxtx_simple_sse.c
@@ -100,12 +100,6 @@ virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
 
 	rte_prefetch0(rused);
 
-	if (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
-		virtio_rxq_rearm_vec(rxvq);
-		if (unlikely(virtqueue_kick_prepare(vq)))
-			virtqueue_notify(vq);
-	}
-
 	nb_total = nb_used;
 	ref_rx_pkts = rx_pkts;
 	for (nb_pkts_received = 0;
@@ -194,5 +188,11 @@ virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
 	for (nb_used = 0; nb_used < nb_pkts_received; nb_used++)
 		virtio_update_packet_stats(&rxvq->stats, ref_rx_pkts[nb_used]);
 
+	if (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
+		virtio_rxq_rearm_vec(rxvq);
+		if (unlikely(virtqueue_kick_prepare(vq)))
+			virtqueue_notify(vq);
+	}
+
 	return nb_pkts_received;
 }
-- 
2.25.1

Re: [dpdk-dev] [PATCH] net/virtio: fix vectorized Rx queue stuck

[Xueming(Steven) Li]

+@谢华伟(此时此刻） <huawei.xhw@alibaba-inc.com>

> -----Original Message-----
> From: Xueming Li <xuemingl@nvidia.com>
> Sent: Wednesday, April 14, 2021 12:27 PM
> Cc: dev@dpdk.org; Xueming(Steven) Li <xuemingl@nvidia.com>; huawei.xie@intel.com; jerin.jacob@caviumnetworks.com;
> drc@linux.vnet.ibm.com; stable@dpdk.org; Maxime Coquelin <maxime.coquelin@redhat.com>; Chenbo Xia <chenbo.xia@intel.com>;
> Jerin Jacob <jerinj@marvell.com>; Ruifeng Wang <ruifeng.wang@arm.com>; Bruce Richardson <bruce.richardson@intel.com>;
> Konstantin Ananyev <konstantin.ananyev@intel.com>; Jianfeng Tan <jianfeng.tan@intel.com>; Jianbo Liu <jianbo.liu@linaro.org>;
> Yuanhan Liu <yuanhan.liu@linux.intel.com>
> Subject: [PATCH] net/virtio: fix vectorized Rx queue stuck
> 
> When Rx burst size >= Rx queue size, all descriptors in used queue consumed without rearm, the next Rx burst found no new packets
> and returned directly without rearm as well.
> 
> This patch rearms available queue at once after rx_burst to avoid vq hungry.
> 
> Fixes: fc3d66212fed ("virtio: add vector Rx")
> Cc: huawei.xie@intel.com
> Fixes: 2d7c37194ee4 ("net/virtio: add NEON based Rx handler")
> Cc: jerin.jacob@caviumnetworks.com
> Fixes: 52b5a707e6ca ("net/virtio: add Altivec Rx")
> Cc: drc@linux.vnet.ibm.com
> Cc: stable@dpdk.org
> 
> Signed-off-by: Xueming Li <xuemingl@nvidia.com>
> ---
>  drivers/net/virtio/virtio_rxtx_simple_altivec.c | 12 ++++++------
>  drivers/net/virtio/virtio_rxtx_simple_neon.c    | 12 ++++++------
>  drivers/net/virtio/virtio_rxtx_simple_sse.c     | 12 ++++++------
>  3 files changed, 18 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/net/virtio/virtio_rxtx_simple_altivec.c b/drivers/net/virtio/virtio_rxtx_simple_altivec.c
> index 62e5100a48..1ffae234da 100644
> --- a/drivers/net/virtio/virtio_rxtx_simple_altivec.c
> +++ b/drivers/net/virtio/virtio_rxtx_simple_altivec.c
> @@ -102,12 +102,6 @@ virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
> 
>  	rte_prefetch0(rused);
> 
> -	if (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
> -		virtio_rxq_rearm_vec(rxvq);
> -		if (unlikely(virtqueue_kick_prepare(vq)))
> -			virtqueue_notify(vq);
> -	}
> -
>  	nb_total = nb_used;
>  	ref_rx_pkts = rx_pkts;
>  	for (nb_pkts_received = 0;
> @@ -204,5 +198,11 @@ virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
>  	for (nb_used = 0; nb_used < nb_pkts_received; nb_used++)
>  		virtio_update_packet_stats(&rxvq->stats, ref_rx_pkts[nb_used]);
> 
> +	if (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
> +		virtio_rxq_rearm_vec(rxvq);
> +		if (unlikely(virtqueue_kick_prepare(vq)))
> +			virtqueue_notify(vq);
> +	}
> +
>  	return nb_pkts_received;
>  }
> diff --git a/drivers/net/virtio/virtio_rxtx_simple_neon.c b/drivers/net/virtio/virtio_rxtx_simple_neon.c
> index c8e4b13a02..341dedce41 100644
> --- a/drivers/net/virtio/virtio_rxtx_simple_neon.c
> +++ b/drivers/net/virtio/virtio_rxtx_simple_neon.c
> @@ -100,12 +100,6 @@ virtio_recv_pkts_vec(void *rx_queue,
> 
>  	rte_prefetch_non_temporal(rused);
> 
> -	if (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
> -		virtio_rxq_rearm_vec(rxvq);
> -		if (unlikely(virtqueue_kick_prepare(vq)))
> -			virtqueue_notify(vq);
> -	}
> -
>  	nb_total = nb_used;
>  	ref_rx_pkts = rx_pkts;
>  	for (nb_pkts_received = 0;
> @@ -210,5 +204,11 @@ virtio_recv_pkts_vec(void *rx_queue,
>  	for (nb_used = 0; nb_used < nb_pkts_received; nb_used++)
>  		virtio_update_packet_stats(&rxvq->stats, ref_rx_pkts[nb_used]);
> 
> +	if (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
> +		virtio_rxq_rearm_vec(rxvq);
> +		if (unlikely(virtqueue_kick_prepare(vq)))
> +			virtqueue_notify(vq);
> +	}
> +
>  	return nb_pkts_received;
>  }
> diff --git a/drivers/net/virtio/virtio_rxtx_simple_sse.c b/drivers/net/virtio/virtio_rxtx_simple_sse.c
> index ff4eba33d6..2e17f9d1f2 100644
> --- a/drivers/net/virtio/virtio_rxtx_simple_sse.c
> +++ b/drivers/net/virtio/virtio_rxtx_simple_sse.c
> @@ -100,12 +100,6 @@ virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
> 
>  	rte_prefetch0(rused);
> 
> -	if (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
> -		virtio_rxq_rearm_vec(rxvq);
> -		if (unlikely(virtqueue_kick_prepare(vq)))
> -			virtqueue_notify(vq);
> -	}
> -
>  	nb_total = nb_used;
>  	ref_rx_pkts = rx_pkts;
>  	for (nb_pkts_received = 0;
> @@ -194,5 +188,11 @@ virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
>  	for (nb_used = 0; nb_used < nb_pkts_received; nb_used++)
>  		virtio_update_packet_stats(&rxvq->stats, ref_rx_pkts[nb_used]);
> 
> +	if (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
> +		virtio_rxq_rearm_vec(rxvq);
> +		if (unlikely(virtqueue_kick_prepare(vq)))
> +			virtqueue_notify(vq);
> +	}
> +
>  	return nb_pkts_received;
>  }
> --
> 2.25.1

[dpdk-dev] [PATCH v1] net/virtio: fix vectorized Rx queue stuck

[Xueming Li]

From: ".Xueming Li" <xuemingl@nvidia.com>

When Rx queue worked in vectorized mode and rxd <= 512, under traffic of
high PPS rate, testpmd often start and receive packets of rxd without
further growth.

Testpmd started with rxq flush which tried to rx MAX_PKT_BURST(512)
packets and drop. When Rx burst size >= Rx queue size, all descriptors
in used queue consumed without rearm, device can't receive more packets.
The next Rx burst returned at once since no used descriptors found,
rearm logic was skipped, rx vq kept in starving state.

To avoid rx vq starving, this patch always check the available queue,
rearm if needed even no used descriptor reported by device.

Fixes: fc3d66212fed ("virtio: add vector Rx")
Cc: 谢华伟(此时此刻） <huawei.xhw@alibaba-inc.com>
Fixes: 2d7c37194ee4 ("net/virtio: add NEON based Rx handler")
Cc: jerin.jacob@caviumnetworks.com
Fixes: 52b5a707e6ca ("net/virtio: add Altivec Rx")
Cc: drc@linux.vnet.ibm.com
Cc: stable@dpdk.org

Signed-off-by: Xueming Li <xuemingl@nvidia.com>
---
 drivers/net/virtio/virtio_rxtx_simple_altivec.c | 12 ++++++------
 drivers/net/virtio/virtio_rxtx_simple_neon.c    | 12 ++++++------
 drivers/net/virtio/virtio_rxtx_simple_sse.c     | 12 ++++++------
 3 files changed, 18 insertions(+), 18 deletions(-)

diff --git a/drivers/net/virtio/virtio_rxtx_simple_altivec.c b/drivers/net/virtio/virtio_rxtx_simple_altivec.c
index 62e5100a48..7534974ef4 100644
--- a/drivers/net/virtio/virtio_rxtx_simple_altivec.c
+++ b/drivers/net/virtio/virtio_rxtx_simple_altivec.c
@@ -85,6 +85,12 @@ virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
 	if (unlikely(nb_pkts < RTE_VIRTIO_DESC_PER_LOOP))
 		return 0;
 
+	if (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
+		virtio_rxq_rearm_vec(rxvq);
+		if (unlikely(virtqueue_kick_prepare(vq)))
+			virtqueue_notify(vq);
+	}
+
 	nb_used = virtqueue_nused(vq);
 
 	rte_compiler_barrier();
@@ -102,12 +108,6 @@ virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
 
 	rte_prefetch0(rused);
 
-	if (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
-		virtio_rxq_rearm_vec(rxvq);
-		if (unlikely(virtqueue_kick_prepare(vq)))
-			virtqueue_notify(vq);
-	}
-
 	nb_total = nb_used;
 	ref_rx_pkts = rx_pkts;
 	for (nb_pkts_received = 0;
diff --git a/drivers/net/virtio/virtio_rxtx_simple_neon.c b/drivers/net/virtio/virtio_rxtx_simple_neon.c
index c8e4b13a02..7fd92d1b0c 100644
--- a/drivers/net/virtio/virtio_rxtx_simple_neon.c
+++ b/drivers/net/virtio/virtio_rxtx_simple_neon.c
@@ -84,6 +84,12 @@ virtio_recv_pkts_vec(void *rx_queue,
 	if (unlikely(nb_pkts < RTE_VIRTIO_DESC_PER_LOOP))
 		return 0;
 
+	if (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
+		virtio_rxq_rearm_vec(rxvq);
+		if (unlikely(virtqueue_kick_prepare(vq)))
+			virtqueue_notify(vq);
+	}
+
 	/* virtqueue_nused has a load-acquire or rte_io_rmb inside */
 	nb_used = virtqueue_nused(vq);
 
@@ -100,12 +106,6 @@ virtio_recv_pkts_vec(void *rx_queue,
 
 	rte_prefetch_non_temporal(rused);
 
-	if (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
-		virtio_rxq_rearm_vec(rxvq);
-		if (unlikely(virtqueue_kick_prepare(vq)))
-			virtqueue_notify(vq);
-	}
-
 	nb_total = nb_used;
 	ref_rx_pkts = rx_pkts;
 	for (nb_pkts_received = 0;
diff --git a/drivers/net/virtio/virtio_rxtx_simple_sse.c b/drivers/net/virtio/virtio_rxtx_simple_sse.c
index ff4eba33d6..7577f5e86d 100644
--- a/drivers/net/virtio/virtio_rxtx_simple_sse.c
+++ b/drivers/net/virtio/virtio_rxtx_simple_sse.c
@@ -85,6 +85,12 @@ virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
 	if (unlikely(nb_pkts < RTE_VIRTIO_DESC_PER_LOOP))
 		return 0;
 
+	if (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
+		virtio_rxq_rearm_vec(rxvq);
+		if (unlikely(virtqueue_kick_prepare(vq)))
+			virtqueue_notify(vq);
+	}
+
 	nb_used = virtqueue_nused(vq);
 
 	if (unlikely(nb_used == 0))
@@ -100,12 +106,6 @@ virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
 
 	rte_prefetch0(rused);
 
-	if (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
-		virtio_rxq_rearm_vec(rxvq);
-		if (unlikely(virtqueue_kick_prepare(vq)))
-			virtqueue_notify(vq);
-	}
-
 	nb_total = nb_used;
 	ref_rx_pkts = rx_pkts;
 	for (nb_pkts_received = 0;
-- 
2.25.1

Re: [dpdk-dev] [PATCH v1] net/virtio: fix vectorized Rx queue stuck

[David Christensen]

> When Rx queue worked in vectorized mode and rxd <= 512, under traffic of
> high PPS rate, testpmd often start and receive packets of rxd without
> further growth.
> 
> Testpmd started with rxq flush which tried to rx MAX_PKT_BURST(512)
> packets and drop. When Rx burst size >= Rx queue size, all descriptors
> in used queue consumed without rearm, device can't receive more packets.
> The next Rx burst returned at once since no used descriptors found,
> rearm logic was skipped, rx vq kept in starving state.
> 
> To avoid rx vq starving, this patch always check the available queue,
> rearm if needed even no used descriptor reported by device.
> 
> Fixes: fc3d66212fed ("virtio: add vector Rx")
> Cc: 谢华伟(此时此刻） <huawei.xhw@alibaba-inc.com>
> Fixes: 2d7c37194ee4 ("net/virtio: add NEON based Rx handler")
> Cc: jerin.jacob@caviumnetworks.com
> Fixes: 52b5a707e6ca ("net/virtio: add Altivec Rx")
> Cc: drc@linux.vnet.ibm.com
> Cc: stable@dpdk.org
> 
> Signed-off-by: Xueming Li <xuemingl@nvidia.com>
> ---
>   drivers/net/virtio/virtio_rxtx_simple_altivec.c | 12 ++++++------
>   drivers/net/virtio/virtio_rxtx_simple_neon.c    | 12 ++++++------
>   drivers/net/virtio/virtio_rxtx_simple_sse.c     | 12 ++++++------
>   3 files changed, 18 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/net/virtio/virtio_rxtx_simple_altivec.c b/drivers/net/virtio/virtio_rxtx_simple_altivec.c
> index 62e5100a48..7534974ef4 100644
> --- a/drivers/net/virtio/virtio_rxtx_simple_altivec.c
> +++ b/drivers/net/virtio/virtio_rxtx_simple_altivec.c
> @@ -85,6 +85,12 @@ virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
>   	if (unlikely(nb_pkts < RTE_VIRTIO_DESC_PER_LOOP))
>   		return 0;
> 
> +	if (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
> +		virtio_rxq_rearm_vec(rxvq);
> +		if (unlikely(virtqueue_kick_prepare(vq)))
> +			virtqueue_notify(vq);
> +	}
> +
>   	nb_used = virtqueue_nused(vq);
> 
>   	rte_compiler_barrier();
> @@ -102,12 +108,6 @@ virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
> 
>   	rte_prefetch0(rused);
> 
> -	if (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
> -		virtio_rxq_rearm_vec(rxvq);
> -		if (unlikely(virtqueue_kick_prepare(vq)))
> -			virtqueue_notify(vq);
> -	}
> -
>   	nb_total = nb_used;
>   	ref_rx_pkts = rx_pkts;
>   	for (nb_pkts_received = 0;

Reviewed-by: David Christensen <drc@linux.vnet.ibm.com>

Re: [dpdk-dev] [PATCH v1] net/virtio: fix vectorized Rx queue stuck

[Maxime Coquelin]

On 4/14/21 4:14 PM, Xueming Li wrote:
> From: ".Xueming Li" <xuemingl@nvidia.com>
> 
> When Rx queue worked in vectorized mode and rxd <= 512, under traffic of
> high PPS rate, testpmd often start and receive packets of rxd without
> further growth.
> 
> Testpmd started with rxq flush which tried to rx MAX_PKT_BURST(512)
> packets and drop. When Rx burst size >= Rx queue size, all descriptors
> in used queue consumed without rearm, device can't receive more packets.
> The next Rx burst returned at once since no used descriptors found,
> rearm logic was skipped, rx vq kept in starving state.
> 
> To avoid rx vq starving, this patch always check the available queue,
> rearm if needed even no used descriptor reported by device.
> 
> Fixes: fc3d66212fed ("virtio: add vector Rx")
> Cc: 谢华伟(此时此刻） <huawei.xhw@alibaba-inc.com>
> Fixes: 2d7c37194ee4 ("net/virtio: add NEON based Rx handler")
> Cc: jerin.jacob@caviumnetworks.com
> Fixes: 52b5a707e6ca ("net/virtio: add Altivec Rx")
> Cc: drc@linux.vnet.ibm.com
> Cc: stable@dpdk.org
> 
> Signed-off-by: Xueming Li <xuemingl@nvidia.com>
> ---
>  drivers/net/virtio/virtio_rxtx_simple_altivec.c | 12 ++++++------
>  drivers/net/virtio/virtio_rxtx_simple_neon.c    | 12 ++++++------
>  drivers/net/virtio/virtio_rxtx_simple_sse.c     | 12 ++++++------
>  3 files changed, 18 insertions(+), 18 deletions(-)
> 

Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Thanks,
Maxime

Re: [dpdk-dev] [PATCH v1] net/virtio: fix vectorized Rx queue stuck

[Maxime Coquelin]

On 4/14/21 4:14 PM, Xueming Li wrote:
> From: ".Xueming Li" <xuemingl@nvidia.com>
> 
> When Rx queue worked in vectorized mode and rxd <= 512, under traffic of
> high PPS rate, testpmd often start and receive packets of rxd without
> further growth.
> 
> Testpmd started with rxq flush which tried to rx MAX_PKT_BURST(512)
> packets and drop. When Rx burst size >= Rx queue size, all descriptors
> in used queue consumed without rearm, device can't receive more packets.
> The next Rx burst returned at once since no used descriptors found,
> rearm logic was skipped, rx vq kept in starving state.
> 
> To avoid rx vq starving, this patch always check the available queue,
> rearm if needed even no used descriptor reported by device.
> 
> Fixes: fc3d66212fed ("virtio: add vector Rx")
> Cc: 谢华伟(此时此刻） <huawei.xhw@alibaba-inc.com>
> Fixes: 2d7c37194ee4 ("net/virtio: add NEON based Rx handler")
> Cc: jerin.jacob@caviumnetworks.com
> Fixes: 52b5a707e6ca ("net/virtio: add Altivec Rx")
> Cc: drc@linux.vnet.ibm.com
> Cc: stable@dpdk.org
> 
> Signed-off-by: Xueming Li <xuemingl@nvidia.com>
> ---
>  drivers/net/virtio/virtio_rxtx_simple_altivec.c | 12 ++++++------
>  drivers/net/virtio/virtio_rxtx_simple_neon.c    | 12 ++++++------
>  drivers/net/virtio/virtio_rxtx_simple_sse.c     | 12 ++++++------
>  3 files changed, 18 insertions(+), 18 deletions(-)
> 

Applied to dpdk-next-virtio/main.

Thanks,
Maxime