Re: [PATCH 1/2] virtio: fix resuming traffic with rx vector path

["Yao, Lei A" <lei.a.yao@intel.com>]

> -----Original Message-----
> From: Maxime Coquelin [mailto:maxime.coquelin@redhat.com]
> Sent: Friday, February 9, 2018 10:27 PM
> To: Bie, Tiwei <tiwei.bie@intel.com>; yliu@fridaylinux.org; Yigit, Ferruh
> <ferruh.yigit@intel.com>; victork@redhat.com
> Cc: dev@dpdk.org; stable@dpdk.org; Wang, Zhihong
> <zhihong.wang@intel.com>; Xu, Qian Q <qian.q.xu@intel.com>; Yao, Lei A
> <lei.a.yao@intel.com>; Maxime Coquelin <maxime.coquelin@redhat.com>
> Subject: [PATCH 1/2] virtio: fix resuming traffic with rx vector path
> 
> This patch fixes traffic resuming issue seen when using
> Rx vector path.
> 
> Fixes: efc83a1e7fc3 ("net/virtio: fix queue setup consistency")
> 
> Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Tested-by: Lei Yao <lei.a.yao@intel.com>
This patch has been tested by regression test suite. It can fix the traffic resume 
issue with vector path.  No performance drop during PVP test:

Following test are also checked and passed:
Vhost/virtio multi queue
Virtio-user
Virtio-user as exception path
Vhost/virtio reconnect

My server info:
OS: Ubuntu 16.04
Kernel: 4.4.0-110
CPU: Intel(R) Xeon(R) CPU E5-2699 v4 @ 2.20GHz

BR
Lei

> ---
>  drivers/net/virtio/virtio_rxtx.c        | 34 ++++++++++++++++++---------------
>  drivers/net/virtio/virtio_rxtx_simple.c |  2 +-
>  drivers/net/virtio/virtio_rxtx_simple.h |  2 +-
>  3 files changed, 21 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
> index 854af399e..505283edd 100644
> --- a/drivers/net/virtio/virtio_rxtx.c
> +++ b/drivers/net/virtio/virtio_rxtx.c
> @@ -30,6 +30,7 @@
>  #include "virtio_pci.h"
>  #include "virtqueue.h"
>  #include "virtio_rxtx.h"
> +#include "virtio_rxtx_simple.h"
> 
>  #ifdef RTE_LIBRTE_VIRTIO_DEBUG_DUMP
>  #define VIRTIO_DUMP_PACKET(m, len) rte_pktmbuf_dump(stdout, m, len)
> @@ -446,25 +447,28 @@ virtio_dev_rx_queue_setup_finish(struct
> rte_eth_dev *dev, uint16_t queue_idx)
>  			&rxvq->fake_mbuf;
>  	}
> 
> -	while (!virtqueue_full(vq)) {
> -		m = rte_mbuf_raw_alloc(rxvq->mpool);
> -		if (m == NULL)
> -			break;
> +	if (hw->use_simple_rx) {
> +		while (vq->vq_free_cnt >=
> RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
> +			virtio_rxq_rearm_vec(rxvq);
> +			nbufs += RTE_VIRTIO_VPMD_RX_REARM_THRESH;
> +		}
> +	} else {
> +		while (!virtqueue_full(vq)) {
> +			m = rte_mbuf_raw_alloc(rxvq->mpool);
> +			if (m == NULL)
> +				break;
> 
> -		/* Enqueue allocated buffers */
> -		if (hw->use_simple_rx)
> -			error = virtqueue_enqueue_recv_refill_simple(vq,
> m);
> -		else
> +			/* Enqueue allocated buffers */
>  			error = virtqueue_enqueue_recv_refill(vq, m);
> -
> -		if (error) {
> -			rte_pktmbuf_free(m);
> -			break;
> +			if (error) {
> +				rte_pktmbuf_free(m);
> +				break;
> +			}
> +			nbufs++;
>  		}
> -		nbufs++;
> -	}
> 
> -	vq_update_avail_idx(vq);
> +		vq_update_avail_idx(vq);
> +	}
> 
>  	PMD_INIT_LOG(DEBUG, "Allocated %d bufs", nbufs);
> 
> diff --git a/drivers/net/virtio/virtio_rxtx_simple.c
> b/drivers/net/virtio/virtio_rxtx_simple.c
> index 7247a0822..0a79d1d5b 100644
> --- a/drivers/net/virtio/virtio_rxtx_simple.c
> +++ b/drivers/net/virtio/virtio_rxtx_simple.c
> @@ -77,7 +77,7 @@ virtio_xmit_pkts_simple(void *tx_queue, struct
> rte_mbuf **tx_pkts,
>  	rte_compiler_barrier();
> 
>  	if (nb_used >= VIRTIO_TX_FREE_THRESH)
> -		virtio_xmit_cleanup(vq);
> +		virtio_xmit_cleanup_simple(vq);
> 
>  	nb_commit = nb_pkts = RTE_MIN((vq->vq_free_cnt >> 1), nb_pkts);
>  	desc_idx = (uint16_t)(vq->vq_avail_idx & desc_idx_max);
> diff --git a/drivers/net/virtio/virtio_rxtx_simple.h
> b/drivers/net/virtio/virtio_rxtx_simple.h
> index 2d8e6b14a..303904d64 100644
> --- a/drivers/net/virtio/virtio_rxtx_simple.h
> +++ b/drivers/net/virtio/virtio_rxtx_simple.h
> @@ -60,7 +60,7 @@ virtio_rxq_rearm_vec(struct virtnet_rx *rxvq)
>  #define VIRTIO_TX_FREE_NR 32
>  /* TODO: vq->tx_free_cnt could mean num of free slots so we could avoid
> shift */
>  static inline void
> -virtio_xmit_cleanup(struct virtqueue *vq)
> +virtio_xmit_cleanup_simple(struct virtqueue *vq)
>  {
>  	uint16_t i, desc_idx;
>  	uint32_t nb_free = 0;
> --
> 2.14.3