----- Original Message -----
>
> Nathan,
>
> >
> > Oh, absolutely - I would also tend to think moving between cgroups would
> > cause widespread issues. AIUI, processes can belong to multiple cgroups
> > however - so, instead of *moving* from existing group(s) into a new group
> > I think we should have an additional pcp group, into which process can be
> > dynamically added/removed - orthogonal to any/all other cgroups they are
> > in already. Then pmlogger and other clients could make use of the proc
> > metrics, as-is, which would be a pre-filtered set of processes.
> >
> Ok. I had assumed processes could only be in one cgroup. I will investigate.
>
Didn't quite work the way I expected initially, but the following magic
incantation appears to give us something we could perhaps work with ...
# mkdir /sys/fs/cgroup/pcp
# mount -t cgroup -o name=pcp,none cgroup /sys/fs/cgroup/pcp
This is on Fedora20 ... other distros, incl. older Fedora/RHEL tend
to mount 'em in other places (and may not support all those options
above, haven't looked) - you can use "pminfo --fetch cgroup.mounts"
to find where they're mounted, or plain old "mount -l -t cgroup".
I'm gonna wander off and continue 3.9.3 release preparations for now, but
I very much looking forward to the results of your own experimentation in
this area.
I keep thinking of interesting new ways we might be able to use this sort
of facility (and ways it could've been used in past deployments I've been
involved in, where chunks of pmdaproc were duplicated and customised for
monitoring specific processes in detail) -- will talk soon.
cheers.
--
Nathan
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