> On Aug 2, 2024, at 00:03, Morten Brørup <m...@smartsharesystems.com> wrote:
>
> External email: Use caution opening links or attachments
>
>
> Optimized the performance of updating the virtio 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 <m...@smartsharesystems.com>
> ---
> v5:
> * Do not inline the function. (Stephen)
> v4:
> * Consider multicast/broadcast packets unlikely.
> v3:
> * Eliminated a local variable.
> * Note: Substituted sizeof(uint32_t)*4 by 32UL, using unsigned long type
> to keep optimal offsetting in generated assembler output.
> * Removed unnecessary curly braces.
> v2:
> * Fixed checkpatch warning about line length.
> ---
> drivers/net/virtio/virtio_rxtx.c | 39 ++++++++++++--------------------
> drivers/net/virtio/virtio_rxtx.h | 4 ++--
> 2 files changed, 16 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/net/virtio/virtio_rxtx.c
> b/drivers/net/virtio/virtio_rxtx.c
> index f69b9453a2..b67f063b31 100644
> --- a/drivers/net/virtio/virtio_rxtx.c
> +++ b/drivers/net/virtio/virtio_rxtx.c
> @@ -82,37 +82,26 @@ vq_ring_free_chain(struct virtqueue *vq, uint16_t
> desc_idx)
> }
>
> void
> -virtio_update_packet_stats(struct virtnet_stats *stats, struct rte_mbuf
> *mbuf)
> +virtio_update_packet_stats(struct virtnet_stats *const stats,
> + const struct rte_mbuf *const mbuf)
> {
> uint32_t s = mbuf->pkt_len;
> - struct rte_ether_addr *ea;
> + const struct rte_ether_addr *const ea =
> + rte_pktmbuf_mtod(mbuf, const struct rte_ether_addr *);
>
> stats->bytes += s;
>
> - if (s == 64) {
> - stats->size_bins[1]++;
> - } else if (s > 64 && s < 1024) {
> - uint32_t bin;
> -
> - /* count zeros, and offset into correct bin */
> - bin = (sizeof(s) * 8) - rte_clz32(s) - 5;
> - stats->size_bins[bin]++;
> - } else {
> - if (s < 64)
> - stats->size_bins[0]++;
> - else if (s < 1519)
> - stats->size_bins[6]++;
> - else
> - stats->size_bins[7]++;
> - }
> + if (s >= 1024)
> + stats->size_bins[6 + (s > 1518)]++;
> + else if (s <= 64)
> + stats->size_bins[s >> 6]++;
> + else
> + stats->size_bins[32UL - rte_clz32(s) - 5]++;
>
> - ea = rte_pktmbuf_mtod(mbuf, struct rte_ether_addr *);
> - if (rte_is_multicast_ether_addr(ea)) {
> - if (rte_is_broadcast_ether_addr(ea))
> - stats->broadcast++;
> - else
> - stats->multicast++;
> - }
> + RTE_BUILD_BUG_ON(offsetof(struct virtnet_stats, broadcast) !=
> + offsetof(struct virtnet_stats, multicast) +
> sizeof(uint64_t));
> + if (unlikely(rte_is_multicast_ether_addr(ea)))
> + (&stats->multicast)[rte_is_broadcast_ether_addr(ea)]++;
> }
>
> static inline void
> diff --git a/drivers/net/virtio/virtio_rxtx.h
> b/drivers/net/virtio/virtio_rxtx.h
> index afc4b74534..68034c914b 100644
> --- a/drivers/net/virtio/virtio_rxtx.h
> +++ b/drivers/net/virtio/virtio_rxtx.h
> @@ -35,7 +35,7 @@ struct virtnet_tx {
> };
>
> int virtio_rxq_vec_setup(struct virtnet_rx *rxvq);
> -void virtio_update_packet_stats(struct virtnet_stats *stats,
> - struct rte_mbuf *mbuf);
> +void virtio_update_packet_stats(struct virtnet_stats *const stats,
> + const struct rte_mbuf *const mbuf);
>
> #endif /* _VIRTIO_RXTX_H_ */
> —
> 2.43.0
>
Reviewed-by: Chenbo Xia <chen...@nvidia.com>
