Re: /proc/lock_stat "stuck"

From: Peter Zijlstra
Date: Wed May 21 2008 - 05:16:39 EST


On Tue, 2008-05-20 at 14:09 -0400, Alan D. Brunelle wrote:
> I'm attempting to use /proc/lock_stat to gather some information during
> some benchmarking runs, but what I find happens is as follows:
>
> 1. I boot the system - 2.6.26-rc3 kernel + CONFIG_LOCK_STAT=y
>
> 2. I can then look at /proc/lock_stat, and it has valid-looking values
>
> 3. I wait a while, do some stuff, but when I look at /proc/lock_stat
> again the values have not changed.
>
> 4. If I clear the counters - echo 0 > /proc/lock_stat - the counters
> never increase, and no information besides the headers are output when I
> cat /proc/lock_stat.
>
>
> Is there something that one needs to do to get counter updates?

Did you get lockdep warnings? Those disable all lock debugging,
including lockstat.

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