On Thu, Oct 12, 2023 at 4:29 PM Jason Wang <jasowang@xxxxxxxxxx> wrote:
>
> On Thu, Oct 12, 2023 at 3:44 PM Heng Qi <hengqi@xxxxxxxxxxxxxxxxx> 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.
Another consideration:
We currently have two TX mode, NAPI by default, and orphan. Simple
pktgen test shows NAPI can only achieve 30% of orphan. So we need to
make sure:
1) dim helps for NAPI, and if NAPI can compete with orphan, we can
drop the orphan code completely which is a great release and
simplification of the codes. And it means we can have BQL, and other
good stuff on top easily.
2) dim doesn't cause regression for orphan
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@xxxxxxxxxxxxxxxxx/
> > [2] https://lore.kernel.org/all/cover.1696745452.git.hengqi@xxxxxxxxxxxxxxxxx/
> >
> > 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
> >
> >
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