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

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Oct 25, 2023 at 09:18:27AM +0800, Jason Wang wrote:
> On Tue, Oct 24, 2023 at 8:03 PM Heng Qi <hengqi@linux.alibaba.com> wrote:
> >
> >
> >
> > 在 2023/10/12 下午4:29, Jason Wang 写道:
> > > On Thu, Oct 12, 2023 at 3:44 PM Heng Qi <hengqi@linux.alibaba.com> 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.
> > > Do you have PPS numbers? And TX numbers are also important as the
> > > throughput could be misleading due to various reasons.
> >
> > Hi Jason!
> >
> > The comparison of rx netdim performance is as follows:
> > (the backend supporting tx dim is not yet ready)
> 
> Thanks a lot for the numbers.
> 
> I'd still expect the TX result as I did play tx interrupt coalescing
> about 10 years ago.
> 
> I will start to review the series but let's try to have some TX numbers as well.
> 
> Btw, it would be more convenient to have a raw PPS benchmark. E.g you
> can try to use a software or hardware packet generator.
> 
> Thanks

Latency results are also kind of interesting.


> >
> >
> > I. Sockperf UDP
> > =================================================
> > 1. Env
> > rxq_0 is affinity to cpu_0
> >
> > 2. Cmd
> > client:  taskset -c 0 sockperf tp -p 8989 -i $IP -t 10 -m 16B
> > server: taskset -c 0 sockperf sr -p 8989
> >
> > 3. Result
> > dim off: 1143277.00 rxpps, throughput 17.844 MBps, cpu is 100%.
> > dim on: 1124161.00 rxpps, throughput 17.610 MBps, cpu is 83.5%.
> > =================================================
> >
> >
> > II. Redis
> > =================================================
> > 1. Env
> > There are 8 rxqs and rxq_i is affinity to cpu_i.
> >
> > 2. Result
> > When all cpus are 100%, ops/sec of memtier_benchmark client is
> > dim off:   978437.23
> > dim on: 1143638.28
> > =================================================
> >
> >
> > III. Nginx
> > =================================================
> > 1. Env
> > There are 8 rxqs and rxq_i is affinity to cpu_i.
> >
> > 2. Result
> > When all cpus are 100%, requests/sec of wrk client is
> > dim off:   877931.67
> > dim on: 1019160.31
> > =================================================
> >
> > Thanks!
> >
> > >
> > > Thanks
> > >
> > >> @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/20230811065512.22190-1-hengqi@linux.alibaba.com/
> > >> [2] https://lore.kernel.org/all/cover.1696745452.git.hengqi@linux.alibaba.com/
> > >>
> > >> 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
> > >>
> > >>
> >
> >