Re: [dpdk-dev] [PATCH] vhost: avoid memory barriers when no descriptors dequeued

2018-10-22 Thread Maxime Coquelin
On 10/22/2018 09:15 AM, Tiwei Bie wrote: On Fri, Oct 19, 2018 at 04:00:58PM +0200, Maxime Coquelin wrote: In both split and packed dequeue paths, flush_shadow_used_ring and vhost_ring_call variants gets called even if not packets have been dequeued, and so no descriptors updates happened. It

Re: [dpdk-dev] [PATCH] vhost: avoid memory barriers when no descriptors dequeued

2018-10-22 Thread Tiwei Bie
On Fri, Oct 19, 2018 at 04:00:58PM +0200, Maxime Coquelin wrote: > In both split and packed dequeue paths, flush_shadow_used_ring > and vhost_ring_call variants gets called even if not packets > have been dequeued, and so no descriptors updates happened. > > It has an impact on CPU pipeline, as me

[dpdk-dev] [PATCH] vhost: avoid memory barriers when no descriptors dequeued

2018-10-19 Thread Maxime Coquelin
In both split and packed dequeue paths, flush_shadow_used_ring and vhost_ring_call variants gets called even if not packets have been dequeued, and so no descriptors updates happened. It has an impact on CPU pipeline, as memory barriers are used in these functions. This patch don't call these fun