Messages in this thread | | | Date | Wed, 10 Jan 2007 10:15:06 -0800 | From | Ulrich Drepper <> | Subject | Re: [PATCH 2.6.20-rc4 1/4] futex priority based wakeup |
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Pierre Peiffer wrote: > But there can be a performance impact when several processes use > different futexes which have the same hash key. > In fact, the plist contains all waiters _of_all_futexes_ having the same > hash key, not only the waiters of a given futex. This can be more a > problem,
s/can be/is/
There are systems with thousands of active futexes, maybe tens of thousands. Not only is hash collision likely, it's also a matter of using and administering the plist. We have to make futexes less connected, not more. Now I definitely want to see real world tests first.
-- ➧ Ulrich Drepper ➧ Red Hat, Inc. ➧ 444 Castro St ➧ Mountain View, CA ❖
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