Messages in this thread | | | Date | Sun, 30 Mar 2008 16:12:18 +0200 | From | Manfred Spraul <> | Subject | Re: Scalability requirements for sysv ipc (+namespaces broken with SEM_UNDO) |
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Mike Galbraith wrote: > On Sat, 2008-03-22 at 20:08 +0100, Manfred Spraul wrote: > > >> just the normal performance of 2.6.25-rc3 is abyssimal, 55 to 60% slower >> than 2.6.18.8: >> > > After manually reverting 3e148c79938aa39035669c1cfa3ff60722134535, > 2.6.25.git scaled linearly We can't just revert that patch: with IDR, a global lock is mandatory :-( We must either revert the whole idea of using IDR or live with the reduced scalability.
Actually, there are further bugs: the undo structures are not namespace-aware, thus semop with SEM_UNDO, unshare, create new array with same id, but more semaphores, another semop with SEM_UNDO will corrupt kernel memory :-( I'll try to clean up the bugs first, then I'll look at the scalability again.
-- Manfred
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