On Mon, Jun 27, 2022 at 07:52:55AM -0700, Shakeel Butt wrote: > On Mon, Jun 27, 2022 at 5:34 AM Feng Tang <feng.tang@xxxxxxxxx> wrote: > > Yes, 1% is just around noise level for a microbenchmark. > > > > I went check the original test data of Oliver's report, the tests was > > run 6 rounds and the performance data is pretty stable (0Day's report > > will show any std deviation bigger than 2%) > > > > The test platform is a 4 sockets 72C/144T machine, and I run the > > same job (nr_tasks = 25% * nr_cpus) on one CascadeLake AP (4 nodes) > > and one Icelake 2 sockets platform, and saw 75% and 53% regresson on > > them. > > > > In the first email, there is a file named 'reproduce', it shows the > > basic test process: > > > > " > > use 'performane' cpufre governor for all CPUs > > > > netserver -4 -D > > modprobe sctp > > netperf -4 -H 127.0.0.1 -t SCTP_STREAM_MANY -c -C -l 300 -- -m 10K & > > netperf -4 -H 127.0.0.1 -t SCTP_STREAM_MANY -c -C -l 300 -- -m 10K & > > netperf -4 -H 127.0.0.1 -t SCTP_STREAM_MANY -c -C -l 300 -- -m 10K & > > (repeat 36 times in total) > > ... > > > > " > > > > Which starts 36 (25% of nr_cpus) netperf clients. And the clients number > > also matters, I tried to increase the client number from 36 to 72(50%), > > and the regression is changed from 69.4% to 73.7% > > > > Am I understanding correctly that this 69.4% (or 73.7%) regression is > with cgroup v2? Yes. > Eric did the experiments on v2 but on real hardware where the > performance impact was negligible. > > BTW do you see similar regression for tcp as well or just sctp? Yes, I run TCP_SENDFILE case with 'send_size'==10K, it hits a 70%+ regressioin. Thanks, Feng
