From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751077AbWDQPF2 (ORCPT ); Mon, 17 Apr 2006 11:05:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751078AbWDQPF2 (ORCPT ); Mon, 17 Apr 2006 11:05:28 -0400 Received: from viper.oldcity.dca.net ([216.158.38.4]:21404 "HELO viper.oldcity.dca.net") by vger.kernel.org with SMTP id S1751077AbWDQPF1 (ORCPT ); Mon, 17 Apr 2006 11:05:27 -0400 Subject: Re: RT question : softirq and minimal user RT priority From: Lee Revell To: markh@compro.net Cc: linux-kernel@vger.kernel.org, Ingo Molnar , Steven Rostedt In-Reply-To: <4443966B.8020802@compro.net> References: <200601131527.00828.Serge.Noiraud@bull.net> <1137167600.7241.22.camel@localhost.localdomain> <4443966B.8020802@compro.net> Content-Type: text/plain Date: Mon, 17 Apr 2006 11:05:24 -0400 Message-Id: <1145286325.16138.26.camel@mindpipe> 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 Please don't trim CC lists On Mon, 2006-04-17 at 09:21 -0400, Mark Hounschell wrote: > Steven Rostedt wrote: > >> Is the smallest usable real-time priority greater than the highest real-time softirq ? > > > > Nope, you can use any rt priority you want. It's up to you whether you > > want to preempt the softirqs or not. Be careful, timers may be preempted > > from delivering signals to high priority processes. I have a patch to > > fix this, but I'm waiting on input from either Thomas Gleixner or Ingo. > > > > -- Steve > > I know this is an old thread but I seem to be having a problem similar > to this and I didn't find any real resolution in the archives. > > I'm using the rt16 patch on 2.6.16.5 with complete preemption. I have a > high priority rt compute bound task that isn't getting signals from a > pci cards interrupt handler. Only when I insure the rt priority of the > task is lower than the rt priority of the irq thread ([IRQ 193]) will my > task receive signals. > > Is this a bug? Is the bug in my interrupt handler? Or is this expected > and acceptable? It's expected if your high priority RT task never gives up the CPU - if this is the case the IRQ thread should have higher priority. Lee