From: Namhyung Kim <namhyung@kernel.org>
To: Tejun Heo <tj@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Jiri Olsa <jolsa@redhat.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Mark Rutland <mark.rutland@arm.com>,
Stephane Eranian <eranian@google.com>,
LKML <linux-kernel@vger.kernel.org>,
linux-perf-users <linux-perf-users@vger.kernel.org>,
Li Zefan <lizefan@huawei.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Adrian Hunter <adrian.hunter@intel.com>
Subject: Re: [PATCH 1/9] perf/core: Add PERF_RECORD_CGROUP event
Date: Sat, 21 Dec 2019 17:49:02 +0900 [thread overview]
Message-ID: <CAM9d7cjmrmyGnYQQ5qUFHYVi2M3kcxt+u+4WQ4PPkoaUgU+5=w@mail.gmail.com> (raw)
In-Reply-To: <20191220151622.GF2914998@devbig004.ftw2.facebook.com>
Hi Tejun,
On Sat, Dec 21, 2019 at 12:16 AM Tejun Heo <tj@kernel.org> wrote:
>
> On Fri, Dec 20, 2019 at 10:33:35AM +0100, Peter Zijlstra wrote:
> > On Fri, Dec 20, 2019 at 01:32:45PM +0900, Namhyung Kim wrote:
> > > To support cgroup tracking, add CGROUP event to save a link between
> > > cgroup path and inode number. The attr.cgroup bit was also added to
> > > enable cgroup tracking from userspace.
> > >
> > > This event will be generated when a new cgroup becomes active.
> > > Userspace might need to synthesize those events for existing cgroups.
> > >
> > > Cc: Tejun Heo <tj@kernel.org>
> > > Cc: Li Zefan <lizefan@huawei.com>
> > > Cc: Johannes Weiner <hannes@cmpxchg.org>
> > > Cc: Adrian Hunter <adrian.hunter@intel.com>
> > > Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> >
> > TJ, is this the right thing to do? ISTR you had concerns on this topic
> > on the past.
>
> Yeah, cgroup->id is now the same as ino (on 64bit ino matchines) and
> fhandle and uniquely identifies a cgroup instance in that boot
> instance. That said, id -> path mapping can be done from userspace by
> passing the cgroup id to open_by_handle_at(2) and then reading the
> symlink in /proc/self/fd, so this event isn't necessary per-se if the
> goal is mapping back ids to paths.
But we should support offline report even on a different machine.
Also cgroups might go away during the record. so I think we need it
anyway.
Thanks
Namhyung
next prev parent reply other threads:[~2019-12-21 8:49 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-20 4:32 [PATCHSET 0/9] perf: Improve cgroup profiling (v2) Namhyung Kim
2019-12-20 4:32 ` [PATCH 1/9] perf/core: Add PERF_RECORD_CGROUP event Namhyung Kim
2019-12-20 9:33 ` Peter Zijlstra
2019-12-20 11:28 ` Namhyung Kim
2019-12-20 11:50 ` Namhyung Kim
2019-12-20 15:16 ` Tejun Heo
2019-12-21 8:49 ` Namhyung Kim [this message]
2019-12-20 4:32 ` [PATCH 2/9] perf/core: Add PERF_SAMPLE_CGROUP feature Namhyung Kim
2019-12-20 9:36 ` Peter Zijlstra
2019-12-20 15:23 ` Tejun Heo
2019-12-20 16:48 ` Peter Zijlstra
2019-12-20 16:59 ` Tejun Heo
2019-12-20 4:32 ` [PATCH 3/9] perf tools: Basic support for CGROUP event Namhyung Kim
2019-12-20 4:32 ` [PATCH 4/9] perf tools: Maintain cgroup hierarchy Namhyung Kim
2019-12-20 4:32 ` [PATCH 5/9] perf report: Add 'cgroup' sort key Namhyung Kim
2019-12-20 4:32 ` [PATCH 6/9] perf record: Support synthesizing cgroup events Namhyung Kim
2019-12-20 4:32 ` [PATCH 7/9] perf record: Add --all-cgroups option Namhyung Kim
2019-12-20 4:32 ` [PATCH 8/9] perf top: " Namhyung Kim
2019-12-20 4:32 ` [PATCH 9/9] perf script: Add --show-cgroup-events option Namhyung Kim
-- strict thread matches above, loose matches on Subject: below --
2020-03-25 12:45 [PATCHSET 0/9] perf: Improve cgroup profiling (v6) Namhyung Kim
2020-03-25 12:45 ` [PATCH 1/9] perf/core: Add PERF_RECORD_CGROUP event Namhyung Kim
2020-01-07 13:34 [PATCHSET 0/9] perf: Improve cgroup profiling (v4) Namhyung Kim
2020-01-07 13:34 ` [PATCH 1/9] perf/core: Add PERF_RECORD_CGROUP event Namhyung Kim
2019-12-23 6:07 [PATCHSET 0/9] perf: Improve cgroup profiling (v3) Namhyung Kim
2019-12-23 6:07 ` [PATCH 1/9] perf/core: Add PERF_RECORD_CGROUP event Namhyung Kim
2019-12-27 4:07 ` kbuild test robot
2020-01-07 12:51 ` Peter Zijlstra
2020-01-07 13:46 ` Namhyung Kim
2019-08-28 7:31 [PATCHSET 0/9] perf: Improve cgroup profiling (v1) Namhyung Kim
2019-08-28 7:31 ` [PATCH 1/9] perf/core: Add PERF_RECORD_CGROUP event Namhyung Kim
2019-08-28 9:44 ` Peter Zijlstra
2019-08-28 9:44 ` Peter Zijlstra
2019-08-28 13:13 ` Arnaldo Carvalho de Melo
2019-08-30 3:46 ` Namhyung Kim
2019-08-30 7:34 ` Peter Zijlstra
2019-08-30 22:49 ` Namhyung Kim
2019-08-30 23:52 ` Stephane Eranian
2019-08-28 14:48 ` Tejun Heo
2019-08-30 3:56 ` Namhyung Kim
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