Re: Using perf with cgroups and containers

[Andi Kleen <andi@firstfloor.org>]

> Is there some where that explain use of the "{}" for event grouping? 

The only good description I know of is in the ucevent documentation.

https://github.com/andikleen/pmu-tools/tree/master/ucevent#grouping-event-scheduling-and-measurement-inaccuracy

Yes the documentation probably needs to be improved (as in many other
ways)

> 
>       -G name,..., --cgroup name,...
>            monitor only in the container (cgroup) called "name". This option
>            is available only in per-cpu mode. The cgroup filesystem must be
>            mounted. All threads belonging to container "name" are monitored
>            when they run on the monitored CPUs. Multiple cgroups can be
>            provided. Each cgroup is applied to the corresponding event, i.e.,
>            first cgroup to first event, second cgroup to second event and so
>            on. It is possible to provide an empty cgroup (monitor all the
>            time) using, e.g., -G foo,,bar. Cgroups must have corresponding
>            events, i.e., they always refer to events defined earlier on the
>            command line.
> 
> The results looks pretty questionable on my machine with the version of perf and kernel I am using:

You're right it doesn't work as I described. Should probably fix it,
my way would make a lot more sense :-)

I guess the current interface was more aimed at scripts.


-Andi
-- 
ak@linux.intel.com -- Speaking for myself only.