From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933364AbWFXJsO (ORCPT ); Sat, 24 Jun 2006 05:48:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933374AbWFXJsO (ORCPT ); Sat, 24 Jun 2006 05:48:14 -0400 Received: from mail.gmx.net ([213.165.64.21]:42381 "HELO mail.gmx.net") by vger.kernel.org with SMTP id S933364AbWFXJsN (ORCPT ); Sat, 24 Jun 2006 05:48:13 -0400 X-Authenticated: #14349625 Subject: Re: Measuring tools - top and interrupts From: Mike Galbraith To: =?ISO-8859-1?Q?Bj=F6rn?= Steinbrink Cc: danial_thom@yahoo.com, linux-kernel@vger.kernel.org In-Reply-To: <20060624092156.GA13142@atjola.homenet> References: <20060622165808.71704.qmail@web33303.mail.mud.yahoo.com> <1151128763.7795.9.camel@Homer.TheSimpsons.net> <1151130383.7545.1.camel@Homer.TheSimpsons.net> <20060624092156.GA13142@atjola.homenet> Content-Type: text/plain; charset=utf-8 Date: Sat, 24 Jun 2006 11:51:56 +0200 Message-Id: <1151142716.7797.10.camel@Homer.TheSimpsons.net> Mime-Version: 1.0 X-Mailer: Evolution 2.4.0 Content-Transfer-Encoding: 8bit X-Y-GMX-Trusted: 0 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2006-06-24 at 11:21 +0200, Björn Steinbrink wrote: > On 2006.06.24 08:26:23 +0200, Mike Galbraith wrote: > > On Sat, 2006-06-24 at 07:59 +0200, Mike Galbraith wrote: > > > On Thu, 2006-06-22 at 09:58 -0700, Danial Thom wrote: > > > > > > > And 75K pps may not be "much", but its still at > > > > least 10% of what the system can handle, so it > > > > should measure around a 10% load. 2.4 measures > > > > about 12% load. So the only conclusion is that > > > > load accounting is broken in 2.6. > > > > > > For UP, yes. SMP kernel accounts irq processing time properly. > > Do you actually see 100% idle? Yes. > On both, UP and SMP, I see non-zero hi/si > values using "top". With IO-APIC enabled, I see only non-zero si values > for my tg3 NICs, and non-zero hi and si values for the nVidia NIC. With > IO-APIC disabled, I also see a non-zero hi value for the tg3 on UP, > guess that's normal... But I never see 100% idle while flooding the box > with pings. I have APIC and IO-APIC enabled. > > For my little box, the below cures it. > > > > --- linux-2.6.17x/arch/i386/kernel/apic.c.org 2006-06-24 08:08:46.000000000 +0200 > > +++ linux-2.6.17x/arch/i386/kernel/apic.c 2006-06-24 08:09:16.000000000 +0200 > > @@ -1175,9 +1175,7 @@ EXPORT_SYMBOL(switch_ipi_to_APIC_timer); > > inline void smp_local_timer_interrupt(struct pt_regs * regs) > > { > > profile_tick(CPU_PROFILING, regs); > > -#ifdef CONFIG_SMP > > update_process_times(user_mode_vm(regs)); > > -#endif > > > > /* > > * We take the 'long' return path, and there every subsystem > > The non-SMP call to update_process_times() is in do_timer_interrupt_hook(), > so I guess the above is not the Right Thing to do. Ah, there it is. That's what I was looking for. I figured that doing what I did had to be wrong, but tried it for grins anyway... was pretty surprised when it worked (kinda). -Mike