Re: [PATCH v3 3/3] perf tool: add cgroup identifier entry in perf report

[Eric W. Biederman]

Hari Bathini <hbathini@xxxxxxxxxxxxxxxxxx> writes:

> This patch introduces a cgroup identifier entry field in perf report to
> identify or distinguish data of different cgroups. It uses the unique
> 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.

In the large this sounds reasonable.

The details are wrong.  The cgroup id needs to be device
number + inode number, not just inode number.

Eric

> Signed-off-by: Hari Bathini <hbathini@xxxxxxxxxxxxxxxxxx>
> ---
>  tools/perf/util/hist.c |    4 ++++
>  tools/perf/util/hist.h |    1 +
>  tools/perf/util/sort.c |   22 ++++++++++++++++++++++
>  tools/perf/util/sort.h |    2 ++
>  4 files changed, 29 insertions(+)
>
> diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c
> @@ -573,9 +575,11 @@ __hists__add_entry(struct hists *hists,
>  		   bool sample_self,
>  		   struct hist_entry_ops *ops)
>  {
> +	struct namespaces *ns = thread__namespaces(al->thread);
>  	struct hist_entry entry = {
>  		.thread	= al->thread,
>  		.comm = thread__comm(al->thread),
> +		.cgroup_id = ns ? ns->inode_num[CGROUP_NS_INDEX] : 0,
>  		.ms = {
>  			.map	= al->map,
>  			.sym	= al->sym,

Eric