Re: [dpdk-dev] [PATCH v2 0/4] vhost: add missing barriers, move prefetching

[Maxime Coquelin <maxime.coquelin@redhat.com>]

On 12/19/18 9:21 AM, Maxime Coquelin wrote:
> This series adds missing read barriers after reading avail index
> for split ring and desc flags for packed ring.
> 
> Also, it turns out that some descriptors prefetching are either
> badly placed, or useless, last part of the series fixes that.
> 
> With the series applied, I get between 0 and 4% gain depending
> on the benchmark (testpmd txonly/rxonly/io).
> 
> Thanks to Jason for reporting the missing read barriers.
> 
> Changes since v1:
> =================
> - Drop volatile removal patch (Ilya)
> - Improve commit messages for RMB patches (Ilya)
> 
> Maxime Coquelin (4):
>    vhost: enforce avail index and desc read ordering
>    vhost: enforce desc flags and content read ordering
>    vhost: prefetch descriptor after the read barrier
>    vhost: remove useless prefetch for packed ring descriptor
> 
>   lib/librte_vhost/virtio_net.c | 27 ++++++++++++++++++++++-----
>   1 file changed, 22 insertions(+), 5 deletions(-)
> 

Applied to dpdk-next-virtio.

Maxime