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    SubjectRe: [PATCH 1/2] perf_events: add support for per-cpu per-cgroup monitoring (v5)
    19:28, Peter Zijlstra wrote:
    > On Thu, 2010-11-18 at 12:40 +0200, Stephane Eranian wrote:
    >> This kernel patch adds the ability to filter monitoring based on
    >> container groups (cgroups). This is for use in per-cpu mode only.
    >> The cgroup to monitor is passed as a file descriptor in the pid
    >> argument to the syscall. The file descriptor must be opened to
    >> the cgroup name in the cgroup filesystem. For instance, if the
    >> cgroup name is foo and cgroupfs is mounted in /cgroup, then the
    >> file descriptor is opened to /cgroup/foo. Cgroup mode is
    >> activated by passing PERF_FLAG_PID_CGROUP in the flags argument
    >> to the syscall.
    >> For instance to measure in cgroup foo on CPU1 assuming
    >> cgroupfs is mounted under /cgroup:
    >> struct perf_event_attr attr;
    >> int cgroup_fd, fd;
    >> cgroup_fd = open("/cgroup/foo", O_RDONLY);
    >> fd = perf_event_open(&attr, cgroup_fd, 1, -1, PERF_FLAG_PID_CGROUP);
    >> close(cgroup_fd);
    >> Signed-off-by: Stephane Eranian <>
    > Could you please split this patch:
    > - pure code movement
    > - time accounting changes
    > - event_filter_match() stuff
    > - cgroup thing
    > From a quick reading it doesn't look bad, but I want an ACK from the
    > cgroup people -- specifically if they're OK with the filedesc juggling
    > thing, because I know the sysfs people objected to such tricks.

    Long long ago, a feature that used this trick was accepted, and that's
    cgroup taskstat.

    You get an fd of a cgroup directory and send it to the kernel via netlink,
    and then you'll receive some statistics, such as how many tasks are
    running/interrupted in that cgroup.

    > Also, it might make sense to add a CONFIG_PERF_CGROUP, even if you want
    > it automagically set if CONFIG_PERF && CONFIG_CGROUP, its easier to find
    > all related code if its under a single CONFIG_var.

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      Last update: 2010-11-26 10:03    [W:0.021 / U:16.460 seconds]
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