From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751259AbVILJbD (ORCPT ); Mon, 12 Sep 2005 05:31:03 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751260AbVILJbD (ORCPT ); Mon, 12 Sep 2005 05:31:03 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:18358 "EHLO mx2.mail.elte.hu") by vger.kernel.org with ESMTP id S1751259AbVILJbB (ORCPT ); Mon, 12 Sep 2005 05:31:01 -0400 Date: Mon, 12 Sep 2005 11:31:36 +0200 From: Ingo Molnar To: Florian Schmidt Cc: "linux-kernel @ vger. kernel. org" , Thomas Gleixner Subject: Re: possible bug in RP kernel Message-ID: <20050912093136.GC5731@elte.hu> References: <20050912105010.701a822f@mango.fruits.de> <20050912090115.GA5731@elte.hu> <20050912111424.1ae2f93e@mango.fruits.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050912111424.1ae2f93e@mango.fruits.de> User-Agent: Mutt/1.4.2.1i X-ELTE-SpamScore: 0.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=0.0 required=5.9 tests=AWL autolearn=disabled SpamAssassin version=3.0.4 0.0 AWL AWL: From: address is in the auto white-list X-ELTE-VirusStatus: clean Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * Florian Schmidt wrote: > On Mon, 12 Sep 2005 11:01:15 +0200 > Ingo Molnar wrote: > > > > 23 seconds gap between two wakeups > > > > > > Maybe my understanding of how sched fifo works is wrong, but i assumed > > > a higher prio thread shold get woken up from a sleep by the scheduler > > > which gets run by the timer interrupt [which is still non > > > preemptible]. > > > > depending on what type of timeout you are using you'll also need to chrt > > the softirq-timer kernel thread(s) to prio 99. Otherwise the timer fn > > will have no chance to be executed. There's work going on by Thomas to > > make such things automatic, by prioritizing timers. If you have HRT > > enabled in the .config then it should mostly be automatic already > > though. > > Ah, > > thanks for the info. So it is a user (me) bug in the end :) This has > helped. Actually the code i had attached had another bug in it. But > that wasn't the responsible one. well, it's not really your 'bug' - the priority setup isnt very intuitive at the moment, and the goal is to automate as much of it as possible. The way various system threads interact is highly implementation dependent, and you shouldnt really be required to know about softirq-timer. We'll try to simplify these things as much as possible. Ingo