> -----Original Message-----
> From: Ding, Xuan <xuan.d...@intel.com>
> Sent: Thursday, July 7, 2022 2:55 PM
> To: maxime.coque...@redhat.com; Xia, Chenbo <chenbo....@intel.com>
> Cc: dev@dpdk.org; Hu, Jiayu <jiayu...@intel.com>; He, Xingguang
> <xingguang...@intel.com>; Yang, YvonneX <yvonnex.y...@intel.com>;
> Jiang, Cheng1 <cheng1.ji...@intel.com>; Ding, Xuan <xuan.d...@intel.com>
> Subject: [PATCH] vhost: fix unnecessary dirty page logging
>
> From: Xuan Ding <xuan.d...@intel.com>
>
> The dirty page logging is only required in vhost enqueue direction for live
> migration. This patch removes the unnecessary dirty page logging in vhost
> dequeue direction. Otherwise, it will result in a performance drop. Some if-
> else judgements are also optimized to improve performance.
>
> Fixes: 6d823bb302c7 ("vhost: prepare sync for descriptor to mbuf
> refactoring")
> Fixes: b6eee3e83402 ("vhost: fix sync dequeue offload")
>
> Signed-off-by: Xuan Ding <xuan.d...@intel.com>
> ---
> lib/vhost/virtio_net.c | 31 +++++++++++++------------------
> 1 file changed, 13 insertions(+), 18 deletions(-)
>
> diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c index
> e842c35fef..12b7fbe7f9 100644
> --- a/lib/vhost/virtio_net.c
> +++ b/lib/vhost/virtio_net.c
> @@ -1113,27 +1113,27 @@ sync_fill_seg(struct virtio_net *dev, struct
> vhost_virtqueue *vq,
> rte_memcpy((void *)((uintptr_t)(buf_addr)),
> rte_pktmbuf_mtod_offset(m, void *,
> mbuf_offset),
> cpy_len);
> + vhost_log_cache_write_iova(dev, vq, buf_iova,
> cpy_len);
> + PRINT_PACKET(dev, (uintptr_t)(buf_addr), cpy_len,
> 0);
> } else {
> rte_memcpy(rte_pktmbuf_mtod_offset(m, void *,
> mbuf_offset),
> (void *)((uintptr_t)(buf_addr)),
> cpy_len);
> }
> - vhost_log_cache_write_iova(dev, vq, buf_iova, cpy_len);
> - PRINT_PACKET(dev, (uintptr_t)(buf_addr), cpy_len, 0);
> } else {
> if (to_desc) {
> batch_copy[vq->batch_copy_nb_elems].dst =
> (void *)((uintptr_t)(buf_addr));
> batch_copy[vq->batch_copy_nb_elems].src =
> rte_pktmbuf_mtod_offset(m, void *,
> mbuf_offset);
> + batch_copy[vq->batch_copy_nb_elems].log_addr =
> buf_iova;
> + batch_copy[vq->batch_copy_nb_elems].len =
> cpy_len;
> } else {
> batch_copy[vq->batch_copy_nb_elems].dst =
> rte_pktmbuf_mtod_offset(m, void *,
> mbuf_offset);
> batch_copy[vq->batch_copy_nb_elems].src =
> (void *)((uintptr_t)(buf_addr));
> }
> - batch_copy[vq->batch_copy_nb_elems].log_addr =
> buf_iova;
> - batch_copy[vq->batch_copy_nb_elems].len = cpy_len;
> vq->batch_copy_nb_elems++;
> }
> }
> @@ -2739,18 +2739,14 @@ desc_to_mbuf(struct virtio_net *dev, struct
> vhost_virtqueue *vq,
> if (async_fill_seg(dev, vq, cur, mbuf_offset,
> buf_iova + buf_offset, cpy_len,
> false) < 0)
> goto error;
> + } else if (likely(hdr && cur == m)) {
> + rte_memcpy(rte_pktmbuf_mtod_offset(cur, void *,
> mbuf_offset),
> + (void *)((uintptr_t)(buf_addr + buf_offset)),
> + cpy_len);
> } else {
> - if (hdr && cur == m) {
> - rte_memcpy(rte_pktmbuf_mtod_offset(cur,
> void *, mbuf_offset),
> - (void *)((uintptr_t)(buf_addr +
> buf_offset)),
> - cpy_len);
> - vhost_log_cache_write_iova(dev, vq,
> buf_iova + buf_offset, cpy_len);
> - PRINT_PACKET(dev, (uintptr_t)(buf_addr +
> buf_offset), cpy_len, 0);
> - } else {
> - sync_fill_seg(dev, vq, cur, mbuf_offset,
> - buf_addr + buf_offset,
> - buf_iova + buf_offset, cpy_len, false);
> - }
> + sync_fill_seg(dev, vq, cur, mbuf_offset,
> + buf_addr + buf_offset,
> + buf_iova + buf_offset, cpy_len, false);
> }
>
> mbuf_avail -= cpy_len;
> @@ -2804,9 +2800,8 @@ desc_to_mbuf(struct virtio_net *dev, struct
> vhost_virtqueue *vq,
> async_iter_finalize(async);
> if (hdr)
> pkts_info[slot_idx].nethdr = *hdr;
> - } else {
> - if (hdr)
> - vhost_dequeue_offload(dev, hdr, m,
> legacy_ol_flags);
> + } else if (hdr) {
> + vhost_dequeue_offload(dev, hdr, m, legacy_ol_flags);
> }
>
> return 0;
> --
> 2.17.1
Reviewed-by: Jiayu Hu <jiayu...@intel.com>
Thanks,
Jiayu
