Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161024AbWAKAKk (ORCPT ); Tue, 10 Jan 2006 19:10:40 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161013AbWAKAKk (ORCPT ); Tue, 10 Jan 2006 19:10:40 -0500 Received: from mustang.oldcity.dca.net ([216.158.38.3]:55509 "HELO mustang.oldcity.dca.net") by vger.kernel.org with SMTP id S1161024AbWAKAKj (ORCPT ); Tue, 10 Jan 2006 19:10:39 -0500 Subject: Re: PCI DMA Interrupt latency From: Lee Revell To: Robert Hancock Cc: linux-kernel In-Reply-To: <43C44A54.5070702@shaw.ca> References: <5trA6-6MD-39@gated-at.bofh.it> <43C44A54.5070702@shaw.ca> Content-Type: text/plain Date: Tue, 10 Jan 2006 19:10:36 -0500 Message-Id: <1136938237.2007.110.camel@mindpipe> Mime-Version: 1.0 X-Mailer: Evolution 2.5.4 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 924 Lines: 22 On Tue, 2006-01-10 at 17:59 -0600, Robert Hancock wrote: > Most likely some driver is disabling interrupts for that period, which > is really longer than it should be. However, if your card/driver require > such tight interrupt latency to function correctly, that seems too > fragile and may not be reliable. Some kind of ringbuffer arrangement > would likely work better, so that the interrupt does not have to be > serviced so soon. > You can easily tell if this is the case by applying these patches: http://people.redhat.com/mingo/latency-tracing-patches/latency-tracing-patches-2.6.15-rc7.tar.gz It says -rc7 but they apply cleanly and work with 2.6.15 final. Lee - 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/