From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932167Ab2DQKKD (ORCPT ); Tue, 17 Apr 2012 06:10:03 -0400 Received: from merlin.infradead.org ([205.233.59.134]:57484 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932096Ab2DQKKC convert rfc822-to-8bit (ORCPT ); Tue, 17 Apr 2012 06:10:02 -0400 Message-ID: <1334657383.28150.78.camel@twins> Subject: Re: A quick view of the performance benchmark for semaphore-like and mutex From: Peter Zijlstra To: "Chen, Dennis (SRDC SW)" Cc: "linux-kernel@vger.kernel.org" , Ingo Molnar , "paulmck@linux.vnet.ibm.com" , Paul Mackerras , Arnaldo Carvalho de Melo Date: Tue, 17 Apr 2012 12:09:43 +0200 In-Reply-To: <491D6B4EAD0A714894D8AD22F4BDE043B15DCF@SCYBEXDAG03.amd.com> References: <491D6B4EAD0A714894D8AD22F4BDE043B15DCF@SCYBEXDAG03.amd.com> Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT X-Mailer: Evolution 3.2.2- Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2012-04-17 at 09:36 +0000, Chen, Dennis (SRDC SW) wrote: > Just as a quick & rough test, with below changes based on mutex (almost the same as semaphore): > > --- /home/dennis/Linux/linux-3.3.2-sem/kernel/mutex.c 2012-04-17 14:59:49.823177615 +0800 > +++ ./mutex.c 2012-04-17 17:00:12.963059284 +0800 > @@ -140,6 +140,7 @@ __mutex_lock_common(struct mutex *lock, > preempt_disable(); > mutex_acquire_nest(&lock->dep_map, subclass, 0, nest_lock, ip); > > +#if 0 > #ifdef CONFIG_MUTEX_SPIN_ON_OWNER > /* > * Optimistic spinning. > @@ -195,6 +196,7 @@ __mutex_lock_common(struct mutex *lock, > arch_mutex_cpu_relax(); > } > #endif > +#endif > spin_lock_mutex(&lock->wait_lock, flags); > > debug_mutex_lock_common(lock, &waiter); or you do: echo NO_OWNER_SPIN > /debug/sched_features