Re: [PATCH][RFC] Adding information of counts processes acquired how many spinlocks to schedstat

[Andi Kleen]

Hitoshi Mitake <mitake@xxxxxxxxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxx -- Speaking for myself only.
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