Messages in this thread | | | From | Josh Don <> | Date | Fri, 20 May 2022 16:09:33 -0700 | Subject | Re: [PATCH] sched/core: add forced idle accounting for cgroups |
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On Fri, May 20, 2022 at 11:43 AM Tejun Heo <tj@kernel.org> wrote: > > Hello, > > Sorry about late reply and thanks for the ping. I missed this one. > > On Fri, May 13, 2022 at 12:23:16PM -0700, Josh Don wrote: > > Yea, that's right, this doesn't require the cpu controller to be > > enabled. Are you suggesting to add a new field to cgroup_base_stat? > > Yes, that's what I meant. I think it'd fit there better.
Sounds good, I'll send a second version of the patch with that change.
> > One other weird artifact of collecting forceidle time is that a cpu > > may account it on behalf of its hyperthread sibling. Currently, the > > core rstat code always accounts to the current cpu's percpu rstat > > field. I can add an accounting function to support writes to a > > different cpu's field, in order to make sure that the per-cpu totals > > are correct (the forceidle accounting code holds rq->__lock, which > > protects all HT siblings of a core). percpu totals aren't currently > > exported in cgroup v2, but this is useful information that we'll > > consume, so it would be nice to keep it accurate. > > Sure, as long as it doesn't incur overhead when not used.
The extra complexity actually doesn't seem to be required. Per-core totals will be accurate, which is the important part.
Thanks, Josh
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