From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932065AbVLaINk (ORCPT ); Sat, 31 Dec 2005 03:13:40 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751313AbVLaINk (ORCPT ); Sat, 31 Dec 2005 03:13:40 -0500 Received: from mail.gmx.net ([213.165.64.21]:32204 "HELO mail.gmx.net") by vger.kernel.org with SMTP id S1751312AbVLaINj (ORCPT ); Sat, 31 Dec 2005 03:13:39 -0500 X-Authenticated: #14349625 Message-Id: <5.2.1.1.2.20051231090255.00bede00@pop.gmx.net> X-Mailer: QUALCOMM Windows Eudora Version 5.2.1 Date: Sat, 31 Dec 2005 09:13:24 +0100 To: Paolo Ornati , Linux Kernel Mailing List From: Mike Galbraith Subject: Re: [SCHED] wrong priority calc - SIMPLE test case Cc: Con Kolivas , Ingo Molnar , Nick Piggin , Peter Williams In-Reply-To: <20051230145221.301faa40@localhost> References: <200512281027.00252.kernel@kolivas.org> <20051227190918.65c2abac@localhost> <20051227224846.6edcff88@localhost> <200512281027.00252.kernel@kolivas.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; format=flowed X-Antivirus: avast! (VPS 0550-0, 12/10/2005), Outbound message X-Antivirus-Status: Clean X-Y-GMX-Trusted: 0 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org At 02:52 PM 12/30/2005 +0100, Paolo Ornati wrote: >WAS: [SCHED] Totally WRONG prority calculation with specific test-case >(since 2.6.10-bk12) >http://lkml.org/lkml/2005/12/27/114/index.html > >On Wed, 28 Dec 2005 10:26:58 +1100 >Con Kolivas wrote: > > > The issue is that the scheduler interactivity estimator is a state > machine and > > can be fooled to some degree, and a cpu intensive task that just > happens to > > sleep a little bit gets significantly better priority than one that is > fully > > cpu bound all the time. Reverting that change is not a solution because it > > can still be fooled by the same process sleeping lots for a few seconds > or so > > at startup and then changing to the cpu mostly-sleeping slightly > behaviour. > > This "fluctuating" behaviour is in my opinion worse which is why I removed > > it. > >Trying to find a "as simple as possible" test case for this problem >(that I consider a BUG in priority calculation) I've come up with this >very simple program: > >------ sched_fooler.c ------------------------------- Ingo seems to have done something in 2.6.15-rc7-rt1 which defeats your little proggy. Taking a quick peek at the rt scheduler changes, nothing poked me in the eye, but by golly, I can't get this kernel to act up, whereas 2.6.14-virgin does. -Mike (off to stare harder rt patch)