From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S267394AbUHPDcY (ORCPT ); Sun, 15 Aug 2004 23:32:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S267398AbUHPDcY (ORCPT ); Sun, 15 Aug 2004 23:32:24 -0400 Received: from mustang.oldcity.dca.net ([216.158.38.3]:48301 "HELO mustang.oldcity.dca.net") by vger.kernel.org with SMTP id S267394AbUHPDcT (ORCPT ); Sun, 15 Aug 2004 23:32:19 -0400 Subject: Re: [patch] voluntary-preempt-2.6.8.1-P0 From: Lee Revell To: Ingo Molnar Cc: Florian Schmidt , linux-kernel , Felipe Alfaro Solana In-Reply-To: <20040816030053.GA10323@elte.hu> References: <1092382825.3450.19.camel@mindpipe> <20040813104817.GI8135@elte.hu> <1092432929.3450.78.camel@mindpipe> <20040814072009.GA6535@elte.hu> <20040815115649.GA26259@elte.hu> <20040816022554.16c3c84a@mango.fruits.de> <1092622121.867.109.camel@krustophenia.net> <20040816023655.GA8746@elte.hu> <1092624221.867.118.camel@krustophenia.net> <20040816025051.GA9481@elte.hu> <20040816030053.GA10323@elte.hu> Content-Type: text/plain Message-Id: <1092627186.867.145.camel@krustophenia.net> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6 Date: Sun, 15 Aug 2004 23:33:07 -0400 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 2004-08-15 at 23:00, Ingo Molnar wrote: > * Ingo Molnar wrote: > > > could this be some DMA starvation effect? Or is this xrun calculated > > from arrival of the audio interrupt (hence DMA completion) to the > > actual running of jackd? > > would there be a way to find out what portion of the xrun is caused by > latencies of the audio card (DMA, etc.) vs. latency from the point jackd > is woken up by the sound-driver to the point jackd preempts the mlock > process and runs? > WHat is being measured is the length of time between jackd is woken up and when it runs - the xrun report prints the difference between the current time and the timestamp returned by snd_pcm_status_get_trigger_tstamp (updated by the interrupt handler) and the current time. jackd prints a different error message if it detects that the interrupt handler was delayed, this is a separate issue than an xrun. I have seen this happen before, but I don't think this is going on here. Lee