From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>, Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
LKML <linux-kernel@vger.kernel.org>,
Stephane Eranian <eranian@google.com>,
Ian Rogers <irogers@google.com>, Andi Kleen <ak@linux.intel.com>
Subject: Re: [PATCH 3/3] tools/lib/fs: Cache cgroupfs mount point
Date: Fri, 19 Feb 2021 08:37:00 -0300 [thread overview]
Message-ID: <YC+i3HDX2H4fB9ea@kernel.org> (raw)
In-Reply-To: <CAM9d7cj=XrpTDQuJ1vhax0drpO8rcbjQgUi3Gj8Q2476U7SmgQ@mail.gmail.com>
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 <acme@kernel.org> 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 <namhyung@kernel.org> 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
prev parent reply other threads:[~2021-02-19 11:37 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-16 9:05 [PATCH 1/3] tools/lib/fs: Prefer cgroup v1 path Namhyung Kim
2020-12-16 9:05 ` [PATCH 2/3] tools/lib/fs: Diet cgroupfs_find_mountpoint() Namhyung Kim
2020-12-28 8:31 ` Jiri Olsa
2020-12-29 5:27 ` Namhyung Kim
2020-12-29 9:39 ` Jiri Olsa
2020-12-16 9:05 ` [PATCH 3/3] tools/lib/fs: Cache cgroupfs mount point Namhyung Kim
2020-12-29 11:51 ` Arnaldo Carvalho de Melo
2021-01-06 1:33 ` Namhyung Kim
2021-01-08 5:51 ` Namhyung Kim
2021-01-21 4:33 ` Namhyung Kim
2021-02-17 12:58 ` Arnaldo Carvalho de Melo
2021-02-19 10:05 ` Namhyung Kim
2021-02-19 11:37 ` Arnaldo Carvalho de Melo [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=YC+i3HDX2H4fB9ea@kernel.org \
--to=acme@kernel.org \
--cc=ak@linux.intel.com \
--cc=alexander.shishkin@linux.intel.com \
--cc=eranian@google.com \
--cc=irogers@google.com \
--cc=jolsa@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mark.rutland@arm.com \
--cc=mingo@kernel.org \
--cc=namhyung@kernel.org \
--cc=peterz@infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox