Re: cgroupstats, plans?

["Paul Menage" <menage@google.com>]

On Tue, Apr 29, 2008 at 5:20 AM, Dhaval Giani <dhaval@linux.vnet.ibm.com> wrote:
> Hi Paul,
>
>  You had mentioned in http://lkml.org/lkml/2008/4/8/29 about cgroup
>  binary API for statistics. What is the status wrt to that?

I've not really had mmore time to work on that since then.

Assuming people are happy with the basic ideas in that post then I
guess the important questions to focus on would be:

- what form should the API description to userspace take? Something
like the cgroup.api file that I proposed a while ago?

- how would the user specify and retrieve a specific set of stats?
should we just dump all stats on each read request, or will that be
too expensive for some stats?

>
>  We are looking to export statistics using libcg. One of the questions
>  that comes up is when is a file in the cgroup, a control file (one used
>  to control the parameters of the subsystem) and when is it a file which
>  is related to statistics.

I don't see why some of them can't be both. If a file has a numerical
value associated with it, is there any reason not to make it available
via the binary stats API, regardless of whether that value was
generated by userspace or the kernel?

Paul