Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754539AbXF3WxW (ORCPT ); Sat, 30 Jun 2007 18:53:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751470AbXF3WxN (ORCPT ); Sat, 30 Jun 2007 18:53:13 -0400 Received: from bizon.gios.gov.pl ([212.244.124.8]:60519 "EHLO bizon.gios.gov.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751330AbXF3WxN (ORCPT ); Sat, 30 Jun 2007 18:53:13 -0400 Date: Sun, 1 Jul 2007 00:53:01 +0200 (CEST) From: Krzysztof Oledzki X-X-Sender: olel@bizon.gios.gov.pl To: Arjan van de Ven cc: linux-kernel@vger.kernel.org Subject: Re: IRQ handling difference between i386 and x86_64 In-Reply-To: <1183218035.2894.13.camel@laptopd505.fenrus.org> Message-ID: References: <1183218035.2894.13.camel@laptopd505.fenrus.org> MIME-Version: 1.0 Content-Type: MULTIPART/MIXED; BOUNDARY="-187430788-1501710822-1183243981=:9268" Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1691 Lines: 46 This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. ---187430788-1501710822-1183243981=:9268 Content-Type: TEXT/PLAIN; charset=ISO-8859-2; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE On Sat, 30 Jun 2007, Arjan van de Ven wrote: > On Sat, 2007-06-30 at 16:55 +0200, Krzysztof Oledzki wrote: >> Hello, >> >> It seems that IRQ handling is somehow different between i386 and x86_64. >> >> In my Dell PowerEdge 1950 is it possible to enable interrupts spreading >> over all CPUs. This a single CPU, four CORE system (Quad-Core E5335 Xeon= ) >> so I think that interrupts migration may be useful. Unfortunately, it >> works only with 32-bit kernel. Booting it with x86_64 leads to situation= , >> when all interrupts goes only to the first cpu matching a smp_affinity >> mask. > > arguably that is the most efficient behavior... round robin of > interrupts is the worst possible case in terms of performance Even on dual/quadro core CPUs with shared cache? So why it is possible to= =20 enable such behaviuor in BIOS, which works only on i386 BTW. :( > are you using irqbalance ? (www.irqbalance.org) Yes, I'm aware about this useful tool, but in some situations (routing=20 for example) it cannot help much as it keeps three cpus idle. :( Best regards, =09=09=09=09Krzysztof Ol=EAdzki ---187430788-1501710822-1183243981=:9268-- - 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/