Re: [PATCH 00/12] perf lock: New subcommand "perf lock", foranalyzing lock statistics

From: Peter Zijlstra
Date: Fri Jan 22 2010 - 11:49:09 EST


On Fri, 2010-01-22 at 11:42 -0500, Jason Baron wrote:
> On Fri, Jan 22, 2010 at 10:39:01PM +0900, Hitoshi Mitake wrote:
> > Adding new subcommand "perf lock" to perf.
> >
>
> looks like a really intresting patch! Does this patch mean that we can
> potentially remove CONFIG_LOCK_STAT, now that the functionality is
> available via 'perf'? Another desire for me has been to able to run
> lockstat on production box. This has not been possible before without
> incurring the performance penalty of lockdep. however, with 'perf' tools
> ability to be turned on an off, perhaps there is (or we can build) a
> mode for lockdep that is lower overhead for this usecase?

boot with: prove_locking=0

This patch still needs all the hooks and bits from lockdep, no way you
want all that in a prodction kernel.

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