Messages in this thread | | | Subject | Re: [PATCH 00/12] perf lock: New subcommand "perf lock", for analyzing lock statistics | From | Peter Zijlstra <> | Date | Fri, 22 Jan 2010 17:52:49 +0100 |
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On Fri, 2010-01-22 at 17:48 +0100, Peter Zijlstra wrote: > 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.
Also, I suspect lockstat to still be lots faster, since it doesn't need to transfer gobs of data but builds the histogram in-kernel.
Having the ability to do in-kernel histrograms with perf is something I've thought about but not yet managed to think of a nice way of doing it.
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