From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751443AbWFTRUR (ORCPT ); Tue, 20 Jun 2006 13:20:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751438AbWFTRUR (ORCPT ); Tue, 20 Jun 2006 13:20:17 -0400 Received: from www.osadl.org ([213.239.205.134]:4799 "EHLO mail.tglx.de") by vger.kernel.org with ESMTP id S1751437AbWFTRUP (ORCPT ); Tue, 20 Jun 2006 13:20:15 -0400 Subject: Re: Why can't I set the priority of softirq-hrt? (Re: 2.6.17-rt1) From: Thomas Gleixner Reply-To: tglx@linutronix.de To: Esben Nielsen Cc: Steven Rostedt , Ingo Molnar , linux-kernel@vger.kernel.org In-Reply-To: References: <20060618070641.GA6759@elte.hu> <1150816429.6780.222.camel@localhost.localdomain> Content-Type: text/plain Date: Tue, 20 Jun 2006 19:21:31 +0200 Message-Id: <1150824092.6780.255.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.6.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2006-06-20 at 19:12 +0100, Esben Nielsen wrote: > > > >> > >> Another complicated design would be to make a task for each priority. > >> Then the interrupt wakes the highest priority one, which handles the first > >> callback and awakes the next one etc. > > > > Don't think that is necessary. > > Me neither :-) Running sofhtirq-hrt at priority 99 - or whatever is > set by chrt - should be sufficient. It is not, that was the reason, why we implemted it. You get arbitrary latencies caused by timer storms. I have to check, whether the priority is propagated when the softirq is blocked on a lock. If not its a bug and has to be fixed. tglx