Messages in this thread | | | Date | Thu, 22 Sep 2016 17:59:20 -0400 | From | Waiman Long <> | Subject | Re: [RFC PATCH v2 3/5] futex: Throughput-optimized (TO) futexes |
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On 09/22/2016 05:41 PM, Thomas Gleixner wrote: > On Thu, 22 Sep 2016, Davidlohr Bueso wrote: >> On Thu, 22 Sep 2016, Waiman Long wrote: >> >>> BTW, my initial attempt for the new futex was to use the same workflow as >>> the PI futexes, but use mutex which has optimistic spinning instead of >>> rt_mutex. >> Btw, Thomas, do you still have any interest pursuing this for rtmutexes from >> -rt into mainline? If so I can resend the patches from a while ago. > Certainly yes. My faint memory tells me that there was some potential issue > due to boosting the owner only if it gets scheduled out, but I might be > wrong.
It is tricky to add optimistic spinning to rtmutexes because of the need to observe process priorities. It is certainly possible to make the top waiter spin, but then I am not sure how much performance gain with just that.
Cheers, Longman
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