Messages in this thread | | | Date | Wed, 22 Sep 2010 12:26:20 +0200 | Subject | Re: [RFC PATCH 0/2] perf_events: add support for per-cpu per-cgroup monitoring (v3) | From | Stephane Eranian <> |
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Hi,
Ok, early testing shows that this seems to be working fine with the pid approach. Of course it is less convenient than just opening a file descriptor in cgroup_fs. There is more bookkeeping involved, incl. cleanup the child on exit.
The other thing is related to how to indicate we want cgroup and not per-thread. For now, my patch is using a new attr.cgroup bit. The alternative is to use a bit in the flags parameter to the syscall.
On Wed, Sep 22, 2010 at 11:18 AM, Balbir Singh <balbir@linux.vnet.ibm.com> wrote: > * 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 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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