[dpdk-dev] [PATCH] virtio: avoid avail ring entry index update if equal

Yuanhan Liu yuanhan.liu at linux.intel.com
Thu Apr 28 08:19:31 CEST 2016

On Wed, Apr 27, 2016 at 04:53:58AM -0400, Huawei Xie wrote:
> Avail ring is updated by the frontend and consumed by the backend.
> There are frequent core to core cache transfers for the avail ring.
> This optmization avoids avail ring entry index update if the entry
> already holds the same value.
> As DPDK virtio PMD implements FIFO free descriptor list (also for
> performance reason of CACHE), in which descriptors are allocated
> from the head and freed to the tail, with this patch in most cases
> avail ring will remain the same, then it would be valid in both caches
> of frontend and backend.

Acked-by: Yuanhan Liu <yuanhan.liu at linux.intel.com>

> Signed-off-by: Huawei Xie <huawei.xie at intel.com>
> Suggested-by: ms >> Michael S. Tsirkin <mst at redhat.com>

And applied to dpdk-next-virtio, with few tiny changes:

- we normally put suggested/reported-by above the SoB.

- removed "ms >>"



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