Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 11 Mar 2003 08:54:28 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 11 Mar 2003 08:54:28 -0500 Received: from pusa.informat.uv.es ([147.156.10.98]:26790 "EHLO pusa.informat.uv.es") by vger.kernel.org with ESMTP id ; Tue, 11 Mar 2003 08:54:27 -0500 Date: Tue, 11 Mar 2003 15:04:58 +0100 To: "Richard B. Johnson" Cc: linux-kernel@vger.kernel.org Subject: Re: is irq smp affinity good for anything? Message-ID: <20030311140458.GA15465@pusa.informat.uv.es> References: <20030311121916.GA12625@pusa.informat.uv.es> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.3.28i From: uaca@alumni.uv.es Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1686 Lines: 46 On Tue, Mar 11, 2003 at 07:40:15AM -0500, Richard B. Johnson wrote: Hi Richard, thanks so much for your reply > On Tue, 11 Mar 2003 uaca@alumni.uv.es wrote: [...] > > 33 MHz machines easily handle 6,000 interrupts per second -- > unless you are trying to execute code within that interrupt > that requires 1/6000th of a second to execute! Perhaps it's > not a "latency" problem, but an interrupt code-bloat problem > where most of the stuff should be executed out of the interrupt > context. it seems I explained too fuzzy/I had to explain it better what I wanted to try is avoidoiding irq latency paths in the CPU where is executing the ISR, where I'm interested not delaying time stamps by any other means. And yes... maybe I'm a little paranoid about this, but doing an echo > /proc/irqs/[0-9]*/smp_affinity is cheap and it's supossed? I should get better results... or not? anyway... I did not expect to increase global latency to these results... and neither to increase latency in the CPU that's receiving just one interrupt! Ulisses PD: I'm not doing a driver, just measuring Debian GNU/Linux: a dream come true ----------------------------------------------------------------------------- "Computers are useless. They can only give answers." Pablo Picasso ---> Visita http://www.valux.org/ para saber acerca de la <--- ---> Asociaci?n Valenciana de Usuarios de Linux <--- - 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/