From: Juergen Beisert Subject: Re: [patch 3/3] Enable setting of IRQ-thread priorities from kernel cmdline. (repost:CC to LKML) Date: Thu, 20 Dec 2007 14:18:16 +0100 Message-ID: <200712201418.17378.jbe@pengutronix.de> References: <20071219194551.315868746@bohmer.net> <3efb10970712200425x4b0ffadcpd2ffa3223eda7b3d@mail.gmail.com> <1985e0f60712200445o4f854cdep6eebf1726737229b@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: "Jaswinder Singh" , "Remy Bohmer" , "Steven Rostedt" , "Arnaldo Carvalho de Melo" , "Ingo Molnar" , "Darren Hart" , "Sven-Thorsten Dietrich" , LKML To: linux-rt-users@vger.kernel.org Return-path: Received: from metis.extern.pengutronix.de ([83.236.181.26]:56740 "EHLO metis.extern.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754155AbXLTNTk convert rfc822-to-8bit (ORCPT ); Thu, 20 Dec 2007 08:19:40 -0500 In-Reply-To: <1985e0f60712200445o4f854cdep6eebf1726737229b@mail.gmail.com> Content-Disposition: inline Sender: linux-rt-users-owner@vger.kernel.org List-ID: On Thursday 20 December 2007 13:45, Jaswinder Singh wrote: > On 12/20/07, Remy Bohmer wrote: > > So, Is this a serious requirement? Should this be possible? > > I have noticed this problem: > root@192.168.1.253:~# cat /proc/loadavgrt > 1.00 1.00 1.00 0/52 1158 > root@192.168.1.253:~# cat /proc/loadavg > 0.00 0.00 0.02 1/52 1159 > root@192.168.1.253:~# > > So I am curious, if possible, user can switch softirq-threads or IRQs > RT tasks to non-RT tasks for slow hardware or least important hardwar= e > for NON-RT tasks. So this will improve RT behaviour. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Why? IMHO: Simply decrease the RT priority of less important IRQs or increas= e all=20 other more important IRQs. IRQs are always more important than other=20 processes in a system, also in non RT systems. Juergen --=20 Dipl.-Ing. Juergen Beisert | http://www.pengutronix.de =A0Pengutronix - Linux Solutions for Science and Industry =A0 Handelsregister: Amtsgericht Hildesheim, HRA 2686 =A0 =A0 =A0 Vertretung Sued/Muenchen, Germany Phone: +49-8766-939 228 | Fax: +49-5121-206917-9