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    SubjectRe: [PATCH][RFC] Adding information of counts processes acquired how many spinlocks to schedstat
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    Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp> writes:

    > Hi,
    >
    > I wrote a test patch which add information of counts processes acquired how many spinlocks to schedstat.
    > After applied this patch, /proc/<PID>/sched will change like this,

    The problem is that spinlocks are very common and schedstats is enabled commonly
    in production kernels. You would need to demonstrate that such a change doesn't
    have significant performance impact. For me it looks like it has.

    Also I'm not sure exactly what good such a metric is. Do you have
    a concrete use case?

    The normal way to check for lock contention or lock bouncingis to
    simply profile cycles or time and see if there is a lot of CPU time in
    locks.

    -Andi

    --
    ak@linux.intel.com -- Speaking for myself only.


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