Re: [PATCH v7 8/8] perf tool: add cgroup identifier entry in perf report

[Hari Bathini <hbathini@linux.vnet.ibm.com>]

On Thursday 02 March 2017 02:46 AM, Arnaldo Carvalho de Melo wrote:
> Em Tue, Feb 21, 2017 at 07:33:13PM +0530, Hari Bathini escreveu:
>> This patch introduces a cgroup identifier entry field in perf report to
>> identify or distinguish data of different cgroups. It uses the device
>> number and inode number of cgroup namespace, included in perf data with
>> the new PERF_RECORD_NAMESPACES event, as cgroup identifier. With the
>> assumption that each container is created with it's own cgroup namespace,
>> this allows assessment/analysis of multiple containers at once.
> Could you try to do this with some real world example? I.e. telling that
> systemd creates some cgroups and then how to map the perf report output
> you show below with what systemd puts in place.
>
> Doing it with docker would be handy as well, no?

Cgroup namespace is a relatively new thing in the kernel (v4.9).
So, I am not sure if there is a real world example for this yet.
A simple test in the meanwhile would be to clone() multiple
processes by passing CLONE_NEWCROUP & SIGCHLD flags to each
process, executing a shell and running different workloads
on each of them while tracing.

> You also forgot to update the documentation with this new sort key,
> please add it in the --sort part of
> tools/perf/Documentation/perf-report.txt.

Sure. Will update.

> Ah, and just another minor request: please format the changeset
> summaries as:
>
>   perf tools: Add cgroup identifier sort order keyword
>
>
> First the component, that in this case is the generic one, as it affects
> multiple tools (top, report), and then start with a capital letter after
> the colon.
>

Sorry. I will take of this in next spin.

Thanks
Hari