From: Tejun Heo <tj@kernel.org>
To: Song Liu <liu.song.a23@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>,
Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
LKML <linux-kernel@vger.kernel.org>, Jiri Olsa <jolsa@redhat.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Stephane Eranian <eranian@google.com>,
Li Zefan <lizefan@huawei.com>,
Johannes Weiner <hannes@cmpxchg.org>
Subject: Re: [PATCH 2/9] perf/core: Add PERF_SAMPLE_CGROUP feature
Date: Mon, 16 Sep 2019 08:23:25 -0700 [thread overview]
Message-ID: <20190916152325.GD3084169@devbig004.ftw2.facebook.com> (raw)
In-Reply-To: <CAPhsuW42ivYU=U5E9jLMWZZgXP_Dv0C_SMFBsiXa53=6bN-=Wg@mail.gmail.com>
Hello, Song.
On Sat, Sep 14, 2019 at 03:02:51PM +0100, Song Liu wrote:
> I think we don't need a perfect identifier in this case. IIUC, the goal of
I really don't want different versions of imperfect identifiers
proliferating.
> this patchset is to map each sample with a cgroup name (or full path).
> To achieve this, we need
>
> 1. PERF_RECORD_CGROUP, that maps
> "64-bit number" => cgroup name/path
> 2. PERF_SAMPLE_CGROUP, that adds "64-bit number" to each sample.
>
> I call the id a "64-bit number" because it is not required to be a globally
> unique id. As long as it is consistent within the same perf-record session,
> we won't get any confusion. Since we add PERF_RECORD_CGROUP
> for each cgroup creation, we will map most of samples correctly even
> when the "64-bit number" is recycled within the same perf-record session.
>
> At the moment, I think ino is good enough for the "64-bit number" even
> for 32-bit systems. If we don't call it "ino" (just call it "cgroup_tag" or
> "cgroup_id", we can change it when kernfs provides a better 64-bit id.
So, a firm nack on this direction.
> About full path name: The user names the full path here. If the user gives
> two different workloads the same name/path, we really cannot change that.
> Reasonable users would be able to make sense from the full path.
I don't see why we wanna be causing this avoidable problem to users.
Thanks.
--
tejun
next prev parent reply other threads:[~2019-09-16 15:23 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
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
2019-08-28 7:31 ` [PATCH 2/9] perf/core: Add PERF_SAMPLE_CGROUP feature Namhyung Kim
2019-08-28 14:49 ` Tejun Heo
2019-08-31 3:03 ` Namhyung Kim
2019-08-31 4:58 ` Tejun Heo
2019-09-03 2:13 ` Namhyung Kim
2019-09-05 16:56 ` Tejun Heo
2019-09-08 13:28 ` Namhyung Kim
2019-09-14 14:02 ` Song Liu
2019-09-16 15:23 ` Tejun Heo [this message]
2019-09-19 6:42 ` Song Liu
2019-09-20 8:47 ` Namhyung Kim
2019-09-20 16:13 ` Song Liu
2019-09-20 21:04 ` Tejun Heo
2019-10-02 6:28 ` Namhyung Kim
2019-10-07 14:16 ` Tejun Heo
2019-08-28 7:31 ` [PATCH 3/9] perf tools: Basic support for CGROUP event Namhyung Kim
2019-08-30 12:55 ` Arnaldo Carvalho de Melo
2019-08-30 22:51 ` Namhyung Kim
2019-08-28 7:31 ` [PATCH 4/9] perf tools: Maintain cgroup hierarchy Namhyung Kim
2019-08-28 7:31 ` [PATCH 5/9] perf report: Add 'cgroup' sort key Namhyung Kim
2019-08-28 7:31 ` [PATCH 6/9] perf record: Support synthesizing cgroup events Namhyung Kim
2019-08-28 7:31 ` [PATCH 7/9] perf record: Add --all-cgroups option Namhyung Kim
2019-08-28 7:31 ` [PATCH 8/9] perf top: " Namhyung Kim
2019-08-28 7:31 ` [PATCH 9/9] perf script: Add --show-cgroup-events option Namhyung Kim
2019-12-20 4:32 [PATCHSET 0/9] perf: Improve cgroup profiling (v2) Namhyung Kim
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
2019-12-23 6:07 [PATCHSET 0/9] perf: Improve cgroup profiling (v3) Namhyung Kim
2019-12-23 6:07 ` [PATCH 2/9] perf/core: Add PERF_SAMPLE_CGROUP feature Namhyung Kim
2020-01-07 13:34 [PATCHSET 0/9] perf: Improve cgroup profiling (v4) Namhyung Kim
2020-01-07 13:34 ` [PATCH 2/9] perf/core: Add PERF_SAMPLE_CGROUP feature Namhyung Kim
2020-03-25 12:45 [PATCHSET 0/9] perf: Improve cgroup profiling (v6) Namhyung Kim
2020-03-25 12:45 ` [PATCH 2/9] perf/core: Add PERF_SAMPLE_CGROUP feature Namhyung Kim
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