From mboxrd@z Thu Jan 1 00:00:00 1970 From: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= Subject: Re: SCHED_RR preempted by SCHED_OTHER Date: Mon, 27 Jul 2009 14:36:09 +0200 Message-ID: <20090727123609.GA26176@pengutronix.de> References: <4A6D962B.20408@alcatel-lucent.fr> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: linux-rt-users@vger.kernel.org To: Denis Richard Return-path: Received: from metis.ext.pengutronix.de ([92.198.50.35]:39464 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752847AbZG0MgK (ORCPT ); Mon, 27 Jul 2009 08:36:10 -0400 Content-Disposition: inline In-Reply-To: <4A6D962B.20408@alcatel-lucent.fr> Sender: linux-rt-users-owner@vger.kernel.org List-ID: On Mon, Jul 27, 2009 at 01:57:31PM +0200, Denis Richard wrote: > Hi all, > We work on powerpc board with kernel 2.6.29.6-rt23. > The kernel is configured with "Complete Preemption (Real-Time)". > Working on our software, we have a strange behavior. > A real time thread (SCHED_RR) can be preempted by non real time one =20 > (SCHED_OTHER). > > We wrote a little test program (at the end of this mail). > This program creates 2 threads, a SCHED_RR one which processes during= =20 > about 12s > (long for a real time, but just for test), and a SCHED_OTHER one, =20 > started after the first one, > which just modifies a global variable. The second one should not run = =20 > during the execution of > the first one. But it appends, the global variable is modified. > > > rr_other > Create thread > OTHER ran during RR > The end > > > > Is it normal, a non real time thread preempts a real time one ? (we =20 > think, it is not) > Or is there something wrong in the test program, the kernel =20 > configuration, ... ? Does # echo -1 > /proc/sys/kernel/sched_rt_runtime_us help? Best regards Uwe --=20 Pengutronix e.K. | Uwe Kleine-K=F6nig = | Industrial Linux Solutions | http://www.pengutronix.= de/ | -- To unsubscribe from this list: send the line "unsubscribe linux-rt-user= s" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html