From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751104AbWGKQrz (ORCPT ); Tue, 11 Jul 2006 12:47:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751102AbWGKQrz (ORCPT ); Tue, 11 Jul 2006 12:47:55 -0400 Received: from e34.co.us.ibm.com ([32.97.110.152]:34509 "EHLO e34.co.us.ibm.com") by vger.kernel.org with ESMTP id S1751104AbWGKQry (ORCPT ); Tue, 11 Jul 2006 12:47:54 -0400 Date: Tue, 11 Jul 2006 09:48:08 -0700 From: Mike Kravetz To: Ingo Molnar , Darren Hart Cc: linux-kernel@vger.kernel.org, Darren Hart , Thomas Gleixner , John Stultz Subject: Re: [RFC PATCH -rt] Priority preemption latency Message-ID: <20060711164808.GA5157@w-mikek2.ibm.com> References: <200606091701.55185.dvhltc@us.ibm.com> <200606102324.58932.dvhltc@us.ibm.com> <20060611073609.GA12456@elte.hu> <200606120838.25200.dvhltc@us.ibm.com> <20060615210658.GA19525@monkey.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060615210658.GA19525@monkey.ibm.com> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi Ingo, As you can see from the note below, we are still having issues with this testcase. As a reminder Darren's mail with a pointer to the new testcase is at: http://www.uwsg.indiana.edu/hypermail/linux/kernel/0606.1/0729.html When run with the '-i' option it fails on a regular (aprox 50% on 4 way) basis. Any insight into what may be happening would be appreciated. Thanks, -- Mike On Thu, Jun 15, 2006 at 02:06:58PM -0700, Mike Kravetz wrote: > On Mon, Jun 12, 2006 at 08:38:24AM -0700, Darren Hart wrote: > > I started running this version of the patch with prio-preemt in a loop > > over 10 hours ago, and it's still running. This seems to be the right fix. > > Unfortunately, this test did eventually fail over in our environment. > John Stultz added the concept of 'interrupter threads' to the testcase. > These high priority RT interrupter threads, occasionally wake up and > run for a short period of time. Since these new threads are higher > priority than any other, they theoretically should not impact the > testcase. This is because the primary purpose of the testcase is to > ensure that lower priority tasks do not run while higher priority tasks > are waiting for a CPU. > > After adding these interrupter threads, the tetscase fails (on a system > here) about 50% of the time. An updated version of prio-preempt.c is > attached. It needs the same headers/makefile/etc as originally provided > by Darren.