Messages in this thread | | | Subject | Re: [RFD 0/9] per-cgroup /proc/stat statistics | From | Peter Zijlstra <> | Date | Wed, 28 Sep 2011 00:11:53 +0200 |
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On Fri, 2011-09-23 at 19:20 -0300, Glauber Costa wrote: > Hi, > > Since I've sent already a RFC about it, I am sending now a RFD. > If you eager for meaning, this can then be a "Request for Doctors", > since Peter is likely to have a heart attack now.
:-)
All we need is to ensure the case of cgroups enabled but not used isn't actually more expensive that what we have now, after that, if people create a 100 deep cgroup hierarchy they get what they asked.
From a conceptual pov this patch-set is a lot saner than the previous one, doesn't duplicate nearly as much and actually tries to improve the code (although I suspect simply killing off cputime64_t as a whole will get us even more).
> So here's the deal: > > * My main goal here was to demonstrate that we can avoid double accounting > in a lot of places. So what I did was getting rid of the original and first > kstat mechanism, and use only cgroups accounting for that. Since the parent > is always updated, the original stats are the one for the root cgroup.
Right, current patch-set won't compile for those who have CGROUP=n kernels though, need to find something for that. Shouldn't be too hard though. It looks like you only need to provide static per-cpu storage and a custom version of task_cgroup_account_field().
> * I believe that all those cpu cgroups are confusing and should be unified. Not > that we can simply get rid of it, but my goal here is to provide all the > information they do, in cpu cgroup. If the set of tasks needed for accounting > is not independent of the ones in cpu cgroup, we can avoid double accounting > for that. I default cpuacct to n, but leave it to people that wants to use it > alone.
Amen! Ideally we place cpuacct on the deprecated list or somesuch..
> * Well, I'm also doing what I was doing originally: Providing a per-cgroup version > of the /proc/stat file.
Right, so how much sense does it make to keep calling it proc.stat?
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