Messages in this thread | | | Date | Thu, 18 Dec 2014 11:40:20 +0800 | From | Zefan Li <> | Subject | Re: [perf tool] cgroup support broken on Debian? |
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>>>> What's the problem here? >>>> >>>> none /sys/fs/cgroup tmpfs rw,relatime,size=4k,mode=755 0 0 >>>> systemd /sys/fs/cgroup/systemd cgroup rw,nosuid,nodev,noexec,relatime,perf_event,name=systemd 0 0 >>>> >>>> cgroup is mounted in /sys/fs/cgroup/systemd, so you should pass '/' to the -G argument: >>>> >>> Is that the only mountpoint possible? >>> The tool needs to detect a valid mount point to locate the named cgroup. >>> That's assuming that if I create cgroup foo, then it appears under >>> //sys/fs/cgroup/systemd/foo >>> >> >> There can be only one cgroupfs mountpoint which has perf_event subsystem >> attached to it. >> >> So for this setup: >> >> mount -t tmpfs /sys/fs/cgroup >> mkdir /sys/fs/cgroup/memory >> mkdir /sys/fs/cgroup/perf >> mount -t cgroup -o memory memcg /sys/fs/cgroup/memory >> mount -t cgroup -o perf_event perf /sys/fs/cgroup/perf >> >> The perf tool will locate the mountpoint as /sys/fs/cgroup/perf. >> > You can mount the cgroup fs for perf_event multiple times. I > tried and it works, though it is useless. >
Yes, but they are the same.
> Vince, I think the correct way to detect which entry is for perf_event > is to look for filesystem type cgroup and option perf_event. It cannot > be anything else. First match is good enough. > .
+1
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