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SubjectRe: AIM7 40% regression with 2.6.26-rc1

* Linus Torvalds <torvalds@linux-foundation.org> wrote:

> I think turning the BKL into a semaphore was fine per se, but that was
> when semaphores were fast.

hm, do we know it for a fact that the 40% AIM regression is due to the
fastpath overhead of the BKL? It would be extraordinary if so.

I think it is far more likely that it's due to the different scheduling
and wakeup behavior of the new kernel/semaphore.c code. So the fix would
be to restore the old scheduling behavior - that's what Yanmin's manual
revert did and that's what got him back the previous AIM7 performance.

Ingo


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