Subject: Re: [PATCH net-next 0/5] virtio-net: support dynamic coalescing moderation

From: "Michael S. Tsirkin" <[email-masked]>
Date: Wed, 1 Nov 2023 06:44:15 -0400

On Wed, Nov 01, 2023 at 05:40:30PM +0800, Heng Qi wrote:
> 
> 
> 在 2023/10/25 下午1:49, Michael S. Tsirkin 写道:
> > On Thu, Oct 12, 2023 at 03:44:04PM +0800, Heng Qi wrote:
> > > Now, virtio-net already supports per-queue moderation parameter
> > > setting. Based on this, we use the netdim library of linux to support
> > > dynamic coalescing moderation for virtio-net.
> > > 
> > > Due to hardware scheduling issues, we only tested rx dim.
> > So patches 1 to 4 look ok but patch 5 is untested - we should
> > probably wait until it's tested properly.
> 
> Hi, Michael.
> 
> For a few reasons (reply to Jason's thread), I won't be trying to push tx
> dim any more in the short term.
> 
> Please review the remaining patches.
> 
> Thanks a lot!

You got a bunch of comments from Jason - want to address them
in a new version then, and I'll review that?

> > 
> > 
> > > @Test env
> > > rxq0 has affinity to cpu0.
> > > 
> > > @Test cmd
> > > client: taskset -c 0 sockperf tp -i ${IP} -t 30 --tcp -m ${msg_size}
> > > server: taskset -c 0 sockperf sr --tcp
> > > 
> > > @Test res
> > > The second column is the ratio of the result returned by client
> > > when rx dim is enabled to the result returned by client when
> > > rx dim is disabled.
> > > 	--------------------------------------
> > > 	| msg_size |  rx_dim=on / rx_dim=off |
> > > 	--------------------------------------
> > > 	|   14B    |         + 3%            |
> > > 	--------------------------------------
> > > 	|   100B   |         + 16%           |
> > > 	--------------------------------------
> > > 	|   500B   |         + 25%           |
> > > 	--------------------------------------
> > > 	|   1400B  |         + 28%           |
> > > 	--------------------------------------
> > > 	|   2048B  |         + 22%           |
> > > 	--------------------------------------
> > > 	|   4096B  |         + 5%            |
> > > 	--------------------------------------
> > > 
> > > ---
> > > This patch set was part of the previous netdim patch set[1].
> > > [1] was split into a merged bugfix set[2] and the current set.
> > > The previous relevant commentators have been Cced.
> > > 
> > > [1] https://lore.kernel.org/all/[email-masked]/
> > > [2] https://lore.kernel.org/all/[email-masked]/
> > > 
> > > Heng Qi (5):
> > >    virtio-net: returns whether napi is complete
> > >    virtio-net: separate rx/tx coalescing moderation cmds
> > >    virtio-net: extract virtqueue coalescig cmd for reuse
> > >    virtio-net: support rx netdim
> > >    virtio-net: support tx netdim
> > > 
> > >   drivers/net/virtio_net.c | 394 ++++++++++++++++++++++++++++++++-------
> > >   1 file changed, 322 insertions(+), 72 deletions(-)
> > > 
> > > -- 
> > > 2.19.1.6.gb485710b