From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753221AbYKQTxO (ORCPT ); Mon, 17 Nov 2008 14:53:14 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751479AbYKQTw7 (ORCPT ); Mon, 17 Nov 2008 14:52:59 -0500 Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:46634 "EHLO sunset.davemloft.net" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751331AbYKQTw6 (ORCPT ); Mon, 17 Nov 2008 14:52:58 -0500 Date: Mon, 17 Nov 2008 11:52:58 -0800 (PST) Message-Id: <20081117.115258.227376348.davem@davemloft.net> To: torvalds@linux-foundation.org Cc: mingo@elte.hu, rjw@sisk.pl, linux-kernel@vger.kernel.org, kernel-testers@vger.kernel.org, cl@linux-foundation.org, efault@gmx.de, a.p.zijlstra@chello.nl Subject: Re: [Bug #11308] tbench regression on each kernel release from 2.6.22 -> 2.6.28 From: David Miller In-Reply-To: References: <20081117110119.GL28786@elte.hu> <20081117.112157.146825192.davem@davemloft.net> X-Mailer: Mew version 6.1 on Emacs 22.1 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Linus Torvalds Date: Mon, 17 Nov 2008 11:48:33 -0800 (PST) > We've asked _you_ to do NMI profiling, it shouldn't be the other way > around. I wasn't able to on these systems, so instead I did cycle level evaluation of the parts that have to run with interrupts disabled. And as a result I found that wake_up() is now 4 times slower than it was in 2.6.22, I even analyzed this for every single kernel release till now. It could be a sparc specific issue, because the call chain is deeper and we eat a lot more register window spills onto the stack. 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 11:52:58 -0800 (PST) Message-ID: <20081117.115258.227376348.davem@davemloft.net> References: <20081117110119.GL28786@elte.hu> <20081117.112157.146825192.davem@davemloft.net> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: kernel-testers-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: Text/Plain; charset="us-ascii" To: torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org Cc: mingo-X9Un+BFzKDI@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 From: Linus Torvalds Date: Mon, 17 Nov 2008 11:48:33 -0800 (PST) > We've asked _you_ to do NMI profiling, it shouldn't be the other way > around. I wasn't able to on these systems, so instead I did cycle level evaluation of the parts that have to run with interrupts disabled. And as a result I found that wake_up() is now 4 times slower than it was in 2.6.22, I even analyzed this for every single kernel release till now. It could be a sparc specific issue, because the call chain is deeper and we eat a lot more register window spills onto the stack.