From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757652AbYDVFIE (ORCPT ); Tue, 22 Apr 2008 01:08:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751884AbYDVFHv (ORCPT ); Tue, 22 Apr 2008 01:07:51 -0400 Received: from elasmtp-curtail.atl.sa.earthlink.net ([209.86.89.64]:60492 "EHLO elasmtp-curtail.atl.sa.earthlink.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751786AbYDVFHu (ORCPT ); Tue, 22 Apr 2008 01:07:50 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=dk20050327; d=mindspring.com; b=ImCGculZPcb2DhQACwaAAI+0je7OgeCHis3f6FKoD0U2dPnsA3Rxq8f0ySy+Ym+f; h=Received:Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References:X-Mailer:Mime-Version:Content-Type:Content-Transfer-Encoding:X-ELNK-Trace:X-Originating-IP; Date: Tue, 22 Apr 2008 01:07:35 -0400 From: Bill Fink To: "Kok, Auke" Cc: Ingo Molnar , Thomas Gleixner , "H. Peter Anvin" , Linux Kernel Mailing List , Anton Titov , Chris Snook , "H. Willstrand" , netdev@vger.kernel.org, Jesse Brandeburg , Linus Torvalds , Andrew Morton Subject: Re: [PATCH] Re: Bad network performance over 2Gbps Message-Id: <20080422010735.8f01efc9.billfink@mindspring.com> In-Reply-To: <48078AF6.2020003@intel.com> References: <1208282804.23631.27.camel@localhost> <175f5a0f0804151315x1e192fc7p7dac1e84fd154211@mail.gmail.com> <48051173.5030802@intel.com> <48051734.1000107@redhat.com> <1208426550.6049.10.camel@localhost> <48078AF6.2020003@intel.com> X-Mailer: Sylpheed 2.4.8 (GTK+ 2.8.6; powerpc-yellowdog-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-ELNK-Trace: c598f748b88b6fd49c7f779228e2f6aeda0071232e20db4d0bff88ce9cb31e5a831bd00faccdda5e350badd9bab72f9c350badd9bab72f9c350badd9bab72f9c X-Originating-IP: 68.48.212.104 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 17 Apr 2008, Kok, Auke wrote: > [X86] IRQBALANCE: Mark as BROKEN and disable by default > > The IRQBALANCE option causes interrupts to bounce all around on SMP systems > quickly burying the CPU in migration cost and cache misses. Mainly affected are > network interrupts and this results in one CPU pegged in softirqd completely. > > Disable this option and provide documentation to a better solution (userspace > irqbalance daemon does overall the best job to begin with and only manual setting > of smp_affinity will beat it). > > Signed-off-by: Auke Kok > > --- > > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig > index 6c70fed..956aa22 100644 > --- a/arch/x86/Kconfig > +++ b/arch/x86/Kconfig > @@ -1026,13 +1026,17 @@ config EFI > platforms. > > config IRQBALANCE > - def_bool y > + def_bool n > prompt "Enable kernel irq balancing" > - depends on X86_32 && SMP && X86_IO_APIC > + depends on X86_32 && SMP && X86_IO_APIC && BROKEN > help > The default yes will allow the kernel to do irq load balancing. > Saying no will keep the kernel from doing irq load balancing. Since you're changing the default setting, shouldn't the above be changed to: Saying yes will allow the kernel to do irq load balancing. The default no will keep the kernel from doing irq load balancing. > + This option is known to cause performance issues on SMP > + systems. The preferred method is to use the userspace > + 'irqbalance' daemon instead. See http://irqbalance.org/. > + > config SECCOMP > def_bool y > prompt "Enable seccomp to safely compute untrusted bytecode" -Bill