Messages in this thread | | | Subject | Re: lockdep oddity | From | Daniel Walker <> | Date | Wed, 06 Sep 2006 07:19:19 -0700 |
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On Wed, 2006-09-06 at 10:40 +0200, Ingo Molnar wrote: > * Hua Zhong <hzhong@gmail.com> wrote: > > > We are just trading accuracy for speed here. > > no, we are trading _both_ accuracy and speed here! a global 'likeliness' > pointer for commonly executed codepaths is causing global cacheline > ping-pongs - which is as bad as it gets.
Up stream or no, would be better for it to again be light weight.
> the right approach, which incidentally would also be perfectly accurate, > is to store an alloc_percpu()-ed pointer at the call site, not the > counter itself.
I don't think it could be done via the macro. If it were called during run time it would have to be special alloc_percpu() that didn't call back into the profiling code (which almost everything does do).
> the current code needs more work before it can go upstream i think.
It was never really planned to go upstream. It's ultimately a debugging feature that's really only needed in -mm ..
Daniel
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