Re: [PATCH 1/9] Remove parent field in cpuacct cgroup

From: Peter Zijlstra
Date: Fri Sep 23 2011 - 10:36:14 EST


On Fri, 2011-09-23 at 13:39 +0530, Balbir Singh wrote:
> >> Android makes heavy use of cpuacct as well. We invented it to do cpu
> >> accounting independent of control
> >
> > But its a massive waste of time to have to iterate a double hierarchy,
> > cache-miss heaven.
> >
>
> By double hierarchy you mean both cpu and cpuacct?

Yes

> What if they are not mounted together?

I was asking if there was a real reason not to have that.

> > Or so people really have independent cgroups as well? I thought people
> > just co-mount all this crap.
> >
>
> Please see
> http://code.google.com/p/cgroupmgr/wiki/cgroupsForAndroid
> http://stackoverflow.com/questions/6814207/android-cpuacct-usage-file
>
> AFAIK, some versions mount cpuacct at /acct and independent of cpu cgroups

They do now, but can that be fixed? Is there a sane use-case?

Overhead really must come down of all this crap.
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