Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1765752AbXILL4O (ORCPT ); Wed, 12 Sep 2007 07:56:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933778AbXILLz7 (ORCPT ); Wed, 12 Sep 2007 07:55:59 -0400 Received: from hu-out-0506.google.com ([72.14.214.239]:64814 "EHLO hu-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933775AbXILLz6 (ORCPT ); Wed, 12 Sep 2007 07:55:58 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=NkEbySNgyIZSSN63TzUD8u3v8+pcXE5Dx0u6gPV/zgC3YdqThsokHEDAYx8gSByMn6n2O8LOEn40brdfKwaK6ng4Xn1PIw6gCIRVsm42g09ls2j7sv13d4CWCqDo4z0nkLp+YMWCDrphCwf+JFD5sQM/z+16ixvIUeKGbbo5gPI= Message-ID: <416aa1ad0709120455l341f1079g9187c13798d310c1@mail.gmail.com> Date: Wed, 12 Sep 2007 17:25:57 +0530 From: "kalash nainwal" To: "Venkat Subbiah" Subject: Re: irq load balancing Cc: linux-kernel@vger.kernel.org In-Reply-To: <3641F7C576757E49AE23AD0D820D72C4232DEA@mailnode1.cranite.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <3641F7C576757E49AE23AD0D820D72C4232DEA@mailnode1.cranite.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1477 Lines: 26 On 9/12/07, Venkat Subbiah wrote: > Most of the load in my system is triggered by a single ethernet IRQ. Essentially the IRQ schedules a tasklet and most of the work is done in the taskelet which is scheduled in the IRQ. From what I read looks like the tasklet would be executed on the same CPU on which it was scheduled. So this means even in an SMP system it will be one processor which is overloaded. > > So will using the user space IRQ loadbalancer really help? What I am doubtful about is that the user space load balance comes along and changes the affinity once in a while. But really what I need is every interrupt to go to a different CPU in a round robin fashion. > > Looks like the APIC can distribute IRQ's dynamically? Is this supported in the kernel and any config or proc interface to turn this on/off. > /proc/irq//smp_affinity. But this is not generally suggested for performance reasons (cache issues etc). > > Thx, > Venkat > > - > 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/ > - 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/