Re: [RFC PATCH] perf: Container-aware tracing support

Ingo Molnar
2015-07-17T12:26:24Z

* Peter Zijlstra <peterz@infradead.org> wrote:

> On Wed, Jul 15, 2015 at 02:38:36PM +0530, Aravinda Prasad wrote:
> > Current tracing infrastructure such as perf and ftrace reports system
> > wide data when invoked inside a container. It is required to restrict
> > events specific to a container context when such tools are invoked
> > inside a container.
> >
> > This RFC patch supports filtering container specific events, without
> > any change in the user interface, when invoked within a container for
> > the perf utility; such support needs to be extended to ftrace. This
> > patch assumes that the debugfs is available within the container and
> > all the processes running inside a container are grouped into a single
> > perf_event subsystem of cgroups. This patch piggybacks on the existing
> > support available for tracing with cgroups [1] by setting the cgrp
> > member of the event structure to the cgroup of the context perf tool
> > is invoked from.
> >
> > However, this patch is not complete and requires more work to fully
> > support tracing inside a container. This patch is intended to initiate
> > the discussion on having container-aware tracing support. A detailed
> > explanation on what is supported and pending issues are mentioned
> > below.
>
> tracing is outside the scope of perf; I suspect you want tracefs to be
> sensitive to filesystem namespaces and all that that entails.

I'd correct that to:

> ftrace is outside the scope of perf; I suspect you want tracefs to be
> sensitive to filesystem namespaces and all that that entails.

because perf very much does tracing as well, we have 'perf trace' for example, and
obviously the whole ring-buffer is a trace buffer and perf.data is a trace dump of
that.

Thanks,

Ingo