On Tue, Aug 06, 2019 at 10:04:15AM +0200, Michal Hocko wrote: > On Tue 06-08-19 15:05:47, kernel test robot wrote: > > Greeting, > > > > FYI, we noticed a -4.1% regression of will-it-scale.per_process_ops due to commit: > > I have to confess I cannot make much sense from numbers because they > seem to be too volatile and the main contributor doesn't stand up for > me. Anyway, regressions on microbenchmarks like this are not all that > surprising when a locking is slightly changed and the critical section > made shorter. I have seen that in the past already. I guess if it's multi process workload. The patch will give more chance to be scheduled out so TLB miss ratio would be bigger than old. I see it's natural trade-off for latency vs. performance so only thing I could think is just increase threshold from 32 to 64 or 128? > > That being said I would still love to get to bottom of this bug rather > than play with the lock duration by a magic. In other words > http://lkml.kernel.org/r/20190730125751.GS9330@xxxxxxxxxxxxxx Yes, if we could remove mark_page_accessed there, it would be best. I added a commen in the thread.
