Re: [PATCH][RFC] Measuring term of acquiring spinlock

From: Ingo Molnar
Date: Fri Nov 13 2009 - 03:17:42 EST



* Hitoshi Mitake <mitake@xxxxxxxxxxxxxxxxxxxxx> wrote:

> From: Ingo Molnar <mingo@xxxxxxx>
> Subject: Re: [PATCH][RFC] Measuring term of acquiring spinlock
> Date: Thu, 12 Nov 2009 08:39:09 +0100
>
> >
> > * Hitoshi Mitake <mitake@xxxxxxxxxxxxxxxxxxxxx> wrote:
> >
> > > * Description
> > >
> > > This patch makes the file spinlock_stats on top of the debugfs.
> > > When user reads this file, some statistical data related to
> > > spinlocks are printed.
> >
> > hm, are you aware of the lockstat tracepoints? They do something
> > like this - and it utilizes perf events to report these events. See
> > include/trace/events/lockdep.h. Needs CONFIG_LOCK_STAT enabled.
> >
>
> Wow, I didn't know that. I'll try it.

Btw., i think we should rename that tracepoint category from 'lockdep'
to 'lock'. It's possible to enable them without CONFIG_PROVE_LOCKING,
and they arent high-overhead in that case.

Ingo
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