Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751394AbVJKGu4 (ORCPT ); Tue, 11 Oct 2005 02:50:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751395AbVJKGu4 (ORCPT ); Tue, 11 Oct 2005 02:50:56 -0400 Received: from ms-smtp-01.nyroc.rr.com ([24.24.2.55]:7866 "EHLO ms-smtp-01.nyroc.rr.com") by vger.kernel.org with ESMTP id S1751394AbVJKGuz (ORCPT ); Tue, 11 Oct 2005 02:50:55 -0400 Date: Tue, 11 Oct 2005 02:46:59 -0400 (EDT) From: Steven Rostedt X-X-Sender: rostedt@localhost.localdomain To: Mark Knecht cc: Daniel Walker , linux-kernel@vger.kernel.org, Ingo Molnar , Lee Revell Subject: Re: Latency data - 2.6.14-rc3-rt13 In-Reply-To: <5bdc1c8b0510102045u7e4bc9eeld5b690b5e96c4a5f@mail.gmail.com> Message-ID: References: <5bdc1c8b0510101316k23ff64e2i231cdea7f11e8553@mail.gmail.com> <1128977359.18782.199.camel@c-67-188-6-232.hsd1.ca.comcast.net> <5bdc1c8b0510101412n714c4798v1482254f6f8e0386@mail.gmail.com> <5bdc1c8b0510101428o475d9dbct2e9bdcc6b46418c9@mail.gmail.com> <1128980674.18782.211.camel@c-67-188-6-232.hsd1.ca.comcast.net> <5bdc1c8b0510101509w4c74028apb6e69746b1b8b65b@mail.gmail.com> <1128983301.18782.215.camel@c-67-188-6-232.hsd1.ca.comcast.net> <5bdc1c8b0510101633lc45fbf8gd2677e5646dc6f93@mail.gmail.com> <5bdc1c8b0510101649s221ab437scc49d6a49269d6b@mail.gmail.com> <5bdc1c8b0510102045u7e4bc9eeld5b690b5e96c4a5f@mail.gmail.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1307 Lines: 34 On Mon, 10 Oct 2005, Mark Knecht wrote: > On 10/10/05, Mark Knecht wrote: > > > > ( softirq-timer/0-3 |#0): new 3997 us maximum-latency critical section. > > So the root cause of this 4mS delay is the 250Hz timer. If I change > the system to use the 1Khz timer then the time in this section drops, > as expected, to 1mS. > > ( softirq-timer/0-3 |#0): new 998 us maximum-latency critical section. > => started at timestamp 121040020: > => ended at timestamp 121041019: > > So, thinking very interesting here I think. > > Back to the drawing board as to my xruns. > Are your xruns showing the same type of latency? If you switch to the 1000Hz do you get only 1mS latency on your xruns too? This sounds like the application might have gone to sleep and didn't wake up until something scheduled it in. Or something else with the scheduler. I doubt that this has to due with preemption or interrupts being off, but something that uses jiffies to calculate. -- Steve - 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/