Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265153AbTFRL5F (ORCPT ); Wed, 18 Jun 2003 07:57:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265165AbTFRL5F (ORCPT ); Wed, 18 Jun 2003 07:57:05 -0400 Received: from hermine.idb.hist.no ([158.38.50.15]:3596 "HELO hermine.idb.hist.no") by vger.kernel.org with SMTP id S265153AbTFRL5D (ORCPT ); Wed, 18 Jun 2003 07:57:03 -0400 Message-ID: <3EF05816.6050307@aitel.hist.no> Date: Wed, 18 Jun 2003 14:16:22 +0200 From: Helge Hafting Organization: AITeL, HiST User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.0.0) Gecko/20020623 Debian/1.0.0-0.woody.1 X-Accept-Language: no, en MIME-Version: 1.0 To: Mike Galbraith CC: Felipe Alfaro Solana , davidm@hpl.hp.com, LKML Subject: Re: O(1) scheduler starvation References: <5.2.0.9.2.20030618113653.0277d780@pop.gmx.net> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1245 Lines: 34 Mike Galbraith wrote: > At 09:53 AM 6/18/2003 +0200, Felipe Alfaro Solana wrote: > >> Hi! >> >> I've been poking around and found the following link on O(1) scheduler >> starvation problems: >> >> http://www.hpl.hp.com/research/linux/kernel/o1-starve.php >> >> The web page contains a small test program which supposedly is able to >> make two processes starvate. However, I've been unable to reproduce what >> is described in the above link. In fact, the CPU usage ratio ranges >> between 60-40% or 70-30% in the worst cases. > > > (you're talking about with my monotinic_clock() diff in your kernel right?) > > If you examine the priorities vs cpu usage, therein lies a big fat bug. > > I think the fundamental problem is that you can only execute in series, > but can sleep in parallel, which makes for more sleep time existing than > all execution time combined. Would dividing the sleep time by the number of sleepers fix this? Or is division a too heavy operation here? Helge Hafting - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/