[PATCH v4 0/3] perf: add support for analyzing events for containers

Alban Crequy alban.crequy at gmail.com
Fri Dec 16 12:14:01 UTC 2016


Hi,

> Currently, there is no trivial mechanism to analyze events based on
> containers. perf -G can be used, but it will not filter events for the
> containers created after perf is invoked, making it difficult to assess/
> analyze performance issues of multiple containers at once.
>
> This patch-set overcomes this limitation by using cgroup identifier as
> container unique identifier. A new PERF_RECORD_NAMESPACES event that
> records namespaces related info is introduced, from which the cgroup
> namespace's device & inode numbers are used as cgroup identifier. This
> is based on the assumption that each container is created with it's own
> cgroup namespace allowing assessment/analysis of multiple containers
> using cgroup identifier.
>
> The first patch introduces PERF_RECORD_NAMESPACES in kernel while the
> second patch makes the corresponding changes in perf tool to read this
> PERF_RECORD_NAMESPACES events. The third patch adds a cgroup identifier
> column in perf report, which contains the cgroup namespace's device and
> inode numbers.

I have a question for the pid namespace: does the new perf event gives
the pid namespace of the task, or the pid_ns_for_children from the
nsproxy? From my limited understanding, v4 seems to do the former, as
opposed to v3.

When synthesizing events from /proc/$PID/ns/pid, it cannot take the
pid_ns_for_children, so I wanted to make sure it is consistent.

Cheers,
Alban


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