Re: [LKP] [lkp] [sctp] a6c2f79287: netperf.Throughput_Mbps -37.2% regression

[Xin Long]

>>>
>>> I'm testing on Linus' master, can we all use that please?
>>>
>>
>> [git] git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
>>
>> [mechine]
>> Intel(R) Xeon(R) CPU E5-2690 v2 @ 3.00GHz
>> mem 62G (66000220K)
>>
>> [system]
>> # cat /etc/redhat-release
>> Red Hat Enterprise Linux Server release 7.3 Beta (Maipo)
>>
>> [commit 3684b03]
>> [root@hp-dl380pg8-11 lxin]# uname -r
>> 4.8.0-rc2.3684b03
>> [root@hp-dl380pg8-11 lxin]# cat test.sh
>> killall -0 netserver || netserver -4 &
>> netperf -4 -t SCTP_STREAM_MANY -c -C -l 300 -- -m 10K -H 127.0.0.1
>
> I just realized the test we are doing is not exactly the same.
> As the original report says:
>         ip: ipv4
>         runtime: 300s
>         nr_threads: 200%
>         cluster: cs-localhost
>         send_size: 10K
>         test: SCTP_STREAM_MANY
>         cpufreq_governor: performance
>
> Note the nr_threads: 200%, which means to start 2 times of CPU number
> processes of netperf.
>
> In our IVB i3(2 cores, 2 threads per core) case, 8 netperf processes
> are started concurrently:
OK, understand.

>
> 2016-07-27 03:48:09 netperf -4 -t SCTP_STREAM_MANY -c -C -l 300 -- -m 10K -H 127.0.0.1 &
> 2016-07-27 03:48:09 netperf -4 -t SCTP_STREAM_MANY -c -C -l 300 -- -m 10K -H 127.0.0.1 &
> 2016-07-27 03:48:09 netperf -4 -t SCTP_STREAM_MANY -c -C -l 300 -- -m 10K -H 127.0.0.1 &
> 2016-07-27 03:48:09 netperf -4 -t SCTP_STREAM_MANY -c -C -l 300 -- -m 10K -H 127.0.0.1 &
> 2016-07-27 03:48:09 netperf -4 -t SCTP_STREAM_MANY -c -C -l 300 -- -m 10K -H 127.0.0.1 &
> 2016-07-27 03:48:09 netperf -4 -t SCTP_STREAM_MANY -c -C -l 300 -- -m 10K -H 127.0.0.1 &
> 2016-07-27 03:48:09 netperf -4 -t SCTP_STREAM_MANY -c -C -l 300 -- -m 10K -H 127.0.0.1 &
> 2016-07-27 03:48:09 netperf -4 -t SCTP_STREAM_MANY -c -C -l 300 -- -m 10K -H 127.0.0.1 &
>
> The throughput is the average of those runs.
>
> And I think we should be doing test on:
> commit a6c2f79287 ("sctp: implement prsctp TTL policy") (the bisected one)
> and
> commit 826d253d57 ("sctp: add SCTP_PR_ASSOC_STATUS on sctp sockopt") (its immediate parent)
> instead of Linus' master HEAD to avoid other factors.
>
OK, I will do tests as your suggestion now,  but need to rebuild again :D

can you disable pr_enable with "sysctl -w net.sctp.prsctp_enable=0",
then try again?