Subject: Re: [PATCH net-next V2 0/3] rx busy polling support for virtio-net

From: "Michael S. Tsirkin" <[email-masked]>
Date: Sun, 20 Jul 2014 23:34:17 +0300

On Wed, Jul 16, 2014 at 02:21:44PM +0800, Jason Wang wrote:
> Hi all:
> 
> This series introduces the support for rx busy polling support. This
> was useful for reduing the latency for a kvm guest. Patch 1-2
> introduces helpers which is used for rx busy polling. Patch 3
> implement the main function.
> 
> Test was done between a kvm guest and an external host. Two hosts were
> connected through 40gb mlx4 cards. With both busy_poll and busy_read are
> set to 50 in guest, 1 byte netperf tcp_rr shows 116% improvement:
> transaction rate was increased from 9151.94 to 19787.37.
> 
> Changes from V1:
> - split the patch info smaller ones
> - add more details about test setup/configuration
> 
> Please review.

Generally I think we should let host know we are polling.
For example, kick the rq or something. Or maybe add another
io address.
Something like this would need a new feature flag though, so I'm fine
with just polling in guest until that is available.

> Jason Wang (3):
>   virtio-net: introduce helpers to enable and disable all NAPIs
>   virtio-net: introduce virtnet_receive()
>   virtio-net: rx busy polling support
> 
>  drivers/net/virtio_net.c | 234 ++++++++++++++++++++++++++++++++++++++++++++---
>  1 file changed, 221 insertions(+), 13 deletions(-)
> 
> -- 
> 1.8.3.1