Messages in this thread | | | Subject | Re: [PATCH 0/2] convert mmap_sem to a scalable rw_mutex | From | Peter Zijlstra <> | Date | Sat, 12 May 2007 12:01:43 +0200 |
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On Sat, 2007-05-12 at 11:27 +0200, Esben Nielsen wrote: > > On Fri, 11 May 2007, Peter Zijlstra wrote: > > > > > I was toying with a scalable rw_mutex and found that it gives ~10% reduction in > > system time on ebizzy runs (without the MADV_FREE patch). > > > > You break priority enheritance on user space futexes! :-( > The problems is that the futex waiter have to take the mmap_sem. And as > your rw_mutex isn't PI enabled you get priority inversions :-(
Do note that rwsems have no PI either. PI is not a concern for mainline - yet, I do have ideas here though.
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