On 25 July 2018 at 00:46, Shakeel Butt <shakeelb@xxxxxxxxxx> wrote: > I ran a simple benchmark which reads the root_mem_cgroup's stat file > 1000 times in the presense of 2500 memcgs on cgroup-v1. The results are: > > Without the patch: > $ time ./read-root-stat-1000-times > > real 0m1.663s > user 0m0.000s > sys 0m1.660s > > With the patch: > $ time ./read-root-stat-1000-times > > real 0m0.468s > user 0m0.000s > sys 0m0.467s Thanks for cc'ing me. I've tried this patch using my test case and the results are interesting. With the patch applied, running my script only generates about 8000 new cgroups, compared to 40,000 before - presumably because the optimisation has altered the timing. On the other hand, if I run the script 5 times to generate 40000 zombie cgroups, the time to get stats for the root cgroup (cgroup-v1) is almost unchanged at around 18ms (was 20ms, but there were slightly more cgroups as well), compared to the almost 4x speedup you're seeing in your test. Regards Bruce -- Bruce Merry Senior Science Processing Developer SKA South Africa
