On 3 May 2017 at 23:49, Tejun Heo <t...@kernel.org> wrote: > On Wed, May 03, 2017 at 03:09:38PM +0200, Peter Zijlstra wrote: >> On Wed, May 03, 2017 at 12:37:37PM +0200, Vincent Guittot wrote: >> > On 3 May 2017 at 11:37, Peter Zijlstra <pet...@infradead.org> wrote: >> >> > > Of course, it could be I overlooked something, in which case, please >> > > tell :-) >> > >> > That's mainly based on the regression i see on my platform. I haven't >> > find the root cause of the regression but it's there which means that >> > using group_entity's load_avg to propagate child cfs_rq >> > runnable_load_avg breaks something >> >> (as mentioned on IRC) >> >> Right.. so looking through the code, (group) se->avg.load_avg is used in >> effective_load() (and thereby wake_affine()) and update_cfs_rq_h_load() >> (and therefore task_h_load()). >> >> So changing it will affect those two functions, which could well lead to >> your regression. > > Ah, okay, that makes sense. I'll try to finish the patch to propagate > runnable without affecting group se->avg.load_avg. BTW, Vincent, did > you boost the weight of the cgroup when you were testing? If you put
I use default group weight > schbench inside a cgroup and have some base load, it is actually > expected to show worse latency. You need to give higher weight to the > cgroup matching the number of active threads (to be accruate, scaled > by duty cycle but shouldn't matter too much in practice). I don't have to change anything cgroup weight with mainline to get good number which means that the base load which is quite close to null, is probably not the problem > > Thanks. > > -- > tejun
