Re: [Bug #11308] tbench regression on each kernel release from 2.6.22 -> 2.6.28

David Miller
2008-11-17T19:36:37Z

From: Ingo Molnar <mingo-X9Un+BFzKDI@public.gmane.org>
Date: Mon, 17 Nov 2008 18:08:44 +0100

> Mike Galbraith has been spending months trying to pin down all the
> issues.

Yes Mike has been doing tireless good work.

Another thing I noticed is that because all of the scheduler
core operations are now function pointer callbacks, the
call chain is deeper for core operations like wake_up().

Much of it used to be completely inlined into try_to_wake_up()

With the addition of the RB tree stuff, that adds yet another
unavoidable depth of function call.

wake_up() is usually at the deepest part of the call chain,
so this is a big deal