[lkml]   [2021]   [Feb]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH 3/3] tools/lib/fs: Cache cgroupfs mount point
Em Fri, Feb 19, 2021 at 07:05:59PM +0900, Namhyung Kim escreveu:
> On Wed, Feb 17, 2021 at 9:58 PM Arnaldo Carvalho de Melo <> wrote:
> > Em Fri, Jan 08, 2021 at 02:51:44PM +0900, Namhyung Kim escreveu:
> > > On Wed, Jan 6, 2021 at 10:33 AM Namhyung Kim <> wrote:

> > > As you said, I think mostly we don't care as the accesses will happen
> > > in a short period of time. But if you really care, maybe for the upcoming
> > > perf daemon changes, I think we can add an API to invalidate the cache
> > > or internal time-based invalidation logic (like remove it after 10 sec.).

> > Ok, we can have something in 'perf daemon' to periodically invalidate
> > this, maybe do a poor man inotify and when asking for the cgroup
> > mountpoint, check some characteristic of that file that changes when it
> > is modified, or plain use a timestamp and have some threshold.

> I thought about this again.

> We don't directly access the cgroups in the perf daemon. It just
> creates new record processes so they'll see a new mountpoint whenever
> they started since this cache is shared within the process only.

> That means we don't need to care about the invalidate in the daemon
> but each perf record and perf stat should do it when they are required
> to do the work repeatedly.

> But looking at the code, the cgroup is set during event parsing (-G
> option) or early in the command (--for-each-cgroup option). So cgroup
> info would not be changed even if the command runs repeatedly.

> So I think you can take the patch as is.

Its in perf/core branch on its way to Linus soon :-)

Thanks for checking it.

- Arnaldo

 \ /
  Last update: 2021-02-19 12:39    [W:0.058 / U:1.700 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site