From: Tejun Heo <tj@kernel.org>
To: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
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@vger.kernel.org, Li Zefan <lizefan@huawei.com>,
Johannes Weiner <hannes@cmpxchg.org>
Subject: Re: [PATCH 2/9] perf/core: Add PERF_SAMPLE_CGROUP feature
Date: Fri, 20 Dec 2019 07:23:24 -0800 [thread overview]
Message-ID: <20191220152324.GG2914998@devbig004.ftw2.facebook.com> (raw)
In-Reply-To: <20191220043253.3278951-3-namhyung@kernel.org>
On Fri, Dec 20, 2019 at 01:32:46PM +0900, Namhyung Kim wrote:
> The PERF_SAMPLE_CGROUP bit is to save (perf_event) cgroup information
> in the sample. It will add a 64-bit id to identify current cgroup and
> it's the file handle in the cgroup file system. Userspace should use
> this information with PERF_RECORD_CGROUP event to match which cgroup
> it belongs.
You don't need PERF_RECORD_CGROUP for that. Something like the
following should work.
struct {
struct file_handle fh;
char stor[MAX_HANDLE_SZ];
} fh_store;
struct file_handle *fh = &fh_store;
fh->handle_type = 0xfe; // FILEID_KERNFS
fh->handle_bytes = sizeof(u64);
*(u64 *)fh->f_handle = cgrp_id;
mnt_fd = open('/sys/fs/cgroup', O_RDONLY);
fd = open_by_handle_at(mnt_fd, fh, O_RDONLY);
snprintf(proc_path, PATH_MAX, "/proc/self/fd/%d", fd);
readlink(proc_path, cgrp_path, PATH_MAX);
--
tejun
next prev parent reply other threads:[~2019-12-20 15:23 UTC|newest]
Thread overview: 37+ 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
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 [this message]
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 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
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
2019-08-28 7:31 [PATCHSET 0/9] perf: Improve cgroup profiling (v1) 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
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
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=20191220152324.GG2914998@devbig004.ftw2.facebook.com \
--to=tj@kernel.org \
--cc=a.p.zijlstra@chello.nl \
--cc=acme@kernel.org \
--cc=alexander.shishkin@linux.intel.com \
--cc=eranian@google.com \
--cc=hannes@cmpxchg.org \
--cc=jolsa@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-perf-users@vger.kernel.org \
--cc=lizefan@huawei.com \
--cc=mark.rutland@arm.com \
--cc=mingo@kernel.org \
--cc=namhyung@kernel.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;
as well as URLs for NNTP newsgroup(s).