Re: Packet gets stuck in NOLOCK pfifo_fast qdisc

[Jike Song]

Hi Josh,

On Fri, Jul 3, 2020 at 2:14 AM Josh Hunt <johunt@xxxxxxxxxx> wrote:
{snip}
> Initial results with Cong's patch look promising, so far no stalls. We
> will let it run over the long weekend and report back on Tuesday.
>
> Paolo - I have concerns about possible performance regression with the
> change as well. If you can gather some data that would be great. If
> things look good with our low throughput test over the weekend we can
> also try assessing performance next week.
>

We met possibly the same problem when testing nvidia/mellanox's
GPUDirect RDMA product, we found that changing NET_SCH_DEFAULT to
DEFAULT_FQ_CODEL mitigated the problem, having no idea why. Maybe you
can also have a try?

Besides, our testing is pretty complex, do you have a quick test to
reproduce it?

-- 
Thanks,
Jike