Re: [fs] a0918006f9: netperf.Throughput_tps -11.6% regression

From: Yin Fengwei
Date: Wed Nov 10 2021 - 22:30:45 EST



On 11/10/2021 4:52 PM, Mickaël Salaün wrote:
>>> ---------------- ---------------------------
>>> %stddev %change %stddev
>>> \ | \
>>> 555600 -0.1% 555305 netperf.Throughput_total_tps
>>> 34725 -0.1% 34706 netperf.Throughput_tps
>>>
>>>
>>> Fengwei also helped review these results and commented:
>>> I suppose these three CPUs have different cache policy. It also could be
>>> related with netperf throughput testing.
>> Does moving the syscall implementation somewhere else change things?
>> That's a _huge_ performance change for something that isn't even called.
>> What's going on here?
> This regression doesn't make sense. I guess this is the result of a
> flaky netperf test, maybe because the test machine was overloaded at
> that time.

I agree the test result looks strange. But I don't think the test machine
or test methodology has issue. It's not possible the test box is overloaded
when test case is running. We did test several times (> 12 times) on different
days. Thanks.


Regards
Yin, Fengwei