From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [Bug #11308] tbench regression on each kernel release from 2.6.22 -> 2.6.28 Date: Mon, 17 Nov 2008 11:36:37 -0800 (PST) Message-ID: <20081117.113637.72930858.davem@davemloft.net> References: <20081117161135.GE12081@elte.hu> <49219D36.5020801@cosmosbay.com> <20081117170844.GJ12081@elte.hu> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20081117170844.GJ12081-X9Un+BFzKDI@public.gmane.org> Sender: kernel-testers-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: Text/Plain; charset="us-ascii" To: mingo-X9Un+BFzKDI@public.gmane.org Cc: dada1-fPLkHRcR87vqlBn2x/YWAg@public.gmane.org, rjw-KKrjLPT3xs0@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, kernel-testers-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, cl-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, efault-Mmb7MZpHnFY@public.gmane.org, a.p.zijlstra-/NLkJaSkS4VmR6Xm/wNWPw@public.gmane.org, torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, shemminger-ZtmgI6mnKB3QT0dZR+AlfA@public.gmane.org From: Ingo Molnar 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