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

From: Michael S. Tsirkin
Date: Sun Jul 20 2014 - 17:31:51 EST


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
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