Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161429AbWJSN5K (ORCPT ); Thu, 19 Oct 2006 09:57:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161432AbWJSN5K (ORCPT ); Thu, 19 Oct 2006 09:57:10 -0400 Received: from gateway-1237.mvista.com ([63.81.120.158]:64233 "EHLO gateway-1237.mvista.com") by vger.kernel.org with ESMTP id S1161429AbWJSN5I (ORCPT ); Thu, 19 Oct 2006 09:57:08 -0400 Subject: Re: + i386-time-avoid-pit-smp-lockups.patch added to -mm tree From: Daniel Walker To: Andi Kleen Cc: linux-kernel@vger.kernel.org, johnstul@us.ibm.com, mingo@elte.hu, tglx@linutronix.de In-Reply-To: <200610191547.09640.ak@suse.de> References: <200610112126.k9BLQqKG002529@shell0.pdx.osdl.net> <1161265475.11264.7.camel@c-67-180-230-165.hsd1.ca.comcast.net> <200610191547.09640.ak@suse.de> Content-Type: text/plain Date: Thu, 19 Oct 2006 06:57:05 -0700 Message-Id: <1161266225.11264.13.camel@c-67-180-230-165.hsd1.ca.comcast.net> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 (2.2.3-2.fc4) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1409 Lines: 34 On Thu, 2006-10-19 at 15:47 +0200, Andi Kleen wrote: > On Thursday 19 October 2006 15:44, Daniel Walker wrote: > > On Wed, 2006-10-11 at 14:26 -0700, akpm@osdl.org wrote: > > > > > diff -puN arch/i386/kernel/i8253.c~i386-time-avoid-pit-smp-lockups arch/i386/kernel/i8253.c > > > --- a/arch/i386/kernel/i8253.c~i386-time-avoid-pit-smp-lockups > > > +++ a/arch/i386/kernel/i8253.c > > > @@ -109,7 +109,7 @@ static struct clocksource clocksource_pi > > > > > > static int __init init_pit_clocksource(void) > > > { > > > - if (num_possible_cpus() > 4) /* PIT does not scale! */ > > > + if (num_possible_cpus() > 1) /* PIT does not scale! */ > > > return 0; > > > > > > > Can we ifdef some code here on CONFIG_SMP . It bugs me that there just > > dead code laying around on smp systems. > > The optimizer should optimize it all out since num_possible_cpus() is a 0 > constant on UP. You just mean the if statement above though? I was talking more about the structure above this called "clocksource_pit" which isn't used on SMP systems due to this code addition. AFAIK init_pit_clocksource() could disappear along with the clocksource structure .. Daniel - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/