Re: [RFC PATCH 0/2] perf_events: add support for per-cpu per-cgroup monitoring (v3)

Balbir Singh
2010-09-22T09:18:44Z

* Peter Zijlstra <peterz@infradead.org> [2010-09-22 09:27:59]:

> On Wed, 2010-09-22 at 09:53 +0530, Balbir Singh wrote:
> > Yes, a task can belong to multiple subsystems, hence multiple cgroups.
> > Ideally we'd want to use pid + subsystem
>
> Apparently we create a perf subsystem, and we only care about that. So
> pid will uniquely identify a cgroup, since for each subsystem a task can
> only belong to one cgroup.

Hmm.. I misread the intention to mean we care about monitoring all
data and aggregate it for each cgroup.

>
> > > One thing we could do is pass this cgroup identifier in the pid field
> > > and use PERF_FLAG_CGROUP or something. Currently the syscall signature
> > > uses pid_t, but I think we can safely change that to int.
> >
> > Or union it and overload the field to contain either pid_t or fd of the cgroup
>
> Its not a field, its an argument.

Thanks!

--
Three Cheers,
Balbir