From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933568AbXGYQas (ORCPT ); Wed, 25 Jul 2007 12:30:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754937AbXGYQai (ORCPT ); Wed, 25 Jul 2007 12:30:38 -0400 Received: from mout1.freenet.de ([195.4.92.91]:40076 "EHLO mout1.freenet.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752559AbXGYQai (ORCPT ); Wed, 25 Jul 2007 12:30:38 -0400 X-Greylist: delayed 3811 seconds by postgrey-1.27 at vger.kernel.org; Wed, 25 Jul 2007 12:30:37 EDT From: Karsten Wiese To: John Sigler Subject: Re: Pin-pointing the root of unusual application latencies Date: Wed, 25 Jul 2007 18:31:34 +0200 User-Agent: KMail/1.9.7 Cc: Ingo Molnar , linux-rt-users@vger.kernel.org, linux-kernel@vger.kernel.org References: <469600F7.3060603@free.fr> <200707251728.00207.fzu@wemgehoertderstaat.de> <46A77054.8040203@free.fr> In-Reply-To: <46A77054.8040203@free.fr> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200707251831.34969.fzu@wemgehoertderstaat.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Am Mittwoch, 25. Juli 2007 schrieb John Sigler: > Karsten Wiese wrote: > > > John Sigler wrote: > > > >> Is there some form of priority inheritance? Does the IRQ handler get a > >> priority boost if a high priority task is waiting for it? > > > > No. But that would be "nice to have". > > No to the first question? to the second question? or to both? :-) > To the second. I checked some soundcard drivers some time ago in -rt kernels, looking for that "priority boosted by consuming process threaded interrupt handler". Then there was no such. > In kernel/futex.c does "PI" stand for Priority Inheritance? > I guess so, yes. > e.g. > > /* > * Priority Inheritance state: > */ > struct futex_pi_state { > /* > * list of 'owned' pi_state instances - these have to be > * cleaned up in do_exit() if the task exits prematurely: > */ > struct list_head list; > > /* > * The PI object: > */ > struct rt_mutex pi_mutex; > > struct task_struct *owner; > atomic_t refcount; > > union futex_key key; > }; > >