vhost-user: optimize stats counters performance

Optimized the performance of updating the statistics counters by reducing
the number of branches.

Ordered the packet size comparisons according to the probability with
typical internet traffic mix.

Signed-off-by: Morten Brørup <mb@smartsharesystems.com>
---
 lib/vhost/virtio_net.c | 40 ++++++++++++++--------------------------
 1 file changed, 14 insertions(+), 26 deletions(-)
  

> On Aug 2, 2024, at 22:32, Morten Brørup <mb@smartsharesystems.com> wrote:
> 
> External email: Use caution opening links or attachments
> 
> 
> Optimized the performance of updating the statistics counters by reducing
> the number of branches.
> 
> Ordered the packet size comparisons according to the probability with
> typical internet traffic mix.
> 
> Signed-off-by: Morten Brørup <mb@smartsharesystems.com>
> ---
> lib/vhost/virtio_net.c | 40 ++++++++++++++--------------------------
> 1 file changed, 14 insertions(+), 26 deletions(-)
> 
> diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c
> index 370402d849..25a495df56 100644
> --- a/lib/vhost/virtio_net.c
> +++ b/lib/vhost/virtio_net.c
> @@ -53,7 +53,7 @@ is_valid_virt_queue_idx(uint32_t idx, int is_tx, uint32_t nr_vring)
> }
> 
> static inline void
> -vhost_queue_stats_update(struct virtio_net *dev, struct vhost_virtqueue *vq,
> +vhost_queue_stats_update(const struct virtio_net *dev, struct vhost_virtqueue *vq,
>                struct rte_mbuf **pkts, uint16_t count)
>        __rte_shared_locks_required(&vq->access_lock)
> {
> @@ -64,37 +64,25 @@ vhost_queue_stats_update(struct virtio_net *dev, struct vhost_virtqueue *vq,
>                return;
> 
>        for (i = 0; i < count; i++) {
> -               struct rte_ether_addr *ea;
> -               struct rte_mbuf *pkt = pkts[i];
> +               const struct rte_ether_addr *ea;
> +               const struct rte_mbuf *pkt = pkts[i];
>                uint32_t pkt_len = rte_pktmbuf_pkt_len(pkt);
> 
>                stats->packets++;
>                stats->bytes += pkt_len;
> 
> -               if (pkt_len == 64) {
> -                       stats->size_bins[1]++;
> -               } else if (pkt_len > 64 && pkt_len < 1024) {
> -                       uint32_t bin;
> -
> -                       /* count zeros, and offset into correct bin */
> -                       bin = (sizeof(pkt_len) * 8) - rte_clz32(pkt_len) - 5;
> -                       stats->size_bins[bin]++;
> -               } else {
> -                       if (pkt_len < 64)
> -                               stats->size_bins[0]++;
> -                       else if (pkt_len < 1519)
> -                               stats->size_bins[6]++;
> -                       else
> -                               stats->size_bins[7]++;
> -               }
> +               if (pkt_len >= 1024)
> +                       stats->size_bins[6 + (pkt_len > 1518)]++;
> +               else if (pkt_len <= 64)
> +                       stats->size_bins[pkt_len >> 6]++;
> +               else
> +                       stats->size_bins[32UL - rte_clz32(pkt_len) - 5]++;
> 
> -               ea = rte_pktmbuf_mtod(pkt, struct rte_ether_addr *);
> -               if (rte_is_multicast_ether_addr(ea)) {
> -                       if (rte_is_broadcast_ether_addr(ea))
> -                               stats->broadcast++;
> -                       else
> -                               stats->multicast++;
> -               }
> +               ea = rte_pktmbuf_mtod(pkt, const struct rte_ether_addr *);
> +               RTE_BUILD_BUG_ON(offsetof(struct virtqueue_stats, broadcast) !=
> +                               offsetof(struct virtqueue_stats, multicast) + sizeof(uint64_t));
> +               if (unlikely(rte_is_multicast_ether_addr(ea)))
> +                       (&stats->multicast)[rte_is_broadcast_ether_addr(ea)]++;
>        }
> }
> 
> --
> 2.43.0
> 

Reviewed-by: Chenbo Xia <chenbox@nvidia.com>
  

On 8/2/24 16:32, Morten Brørup wrote:
> Optimized the performance of updating the statistics counters by reducing
> the number of branches.
> 
> Ordered the packet size comparisons according to the probability with
> typical internet traffic mix.
> 
> Signed-off-by: Morten Brørup <mb@smartsharesystems.com>
> ---
>   lib/vhost/virtio_net.c | 40 ++++++++++++++--------------------------
>   1 file changed, 14 insertions(+), 26 deletions(-)
> 

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

Thanks,
Maxime
  

On 8/2/24 16:32, Morten Brørup wrote:
> Optimized the performance of updating the statistics counters by reducing
> the number of branches.
> 
> Ordered the packet size comparisons according to the probability with
> typical internet traffic mix.
> 
> Signed-off-by: Morten Brørup <mb@smartsharesystems.com>
> ---
>   lib/vhost/virtio_net.c | 40 ++++++++++++++--------------------------
>   1 file changed, 14 insertions(+), 26 deletions(-)
> 

Applied to next-virtio/for-next-net.

Thanks,
Maxime