Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964870AbVLJQYY (ORCPT ); Sat, 10 Dec 2005 11:24:24 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932387AbVLJQYY (ORCPT ); Sat, 10 Dec 2005 11:24:24 -0500 Received: from embla.aitel.hist.no ([158.38.50.22]:60652 "HELO embla.aitel.hist.no") by vger.kernel.org with SMTP id S932359AbVLJQYY (ORCPT ); Sat, 10 Dec 2005 11:24:24 -0500 Date: Sat, 10 Dec 2005 17:27:59 +0100 To: Linus Torvalds Cc: Linux Kernel Mailing List Subject: Re: Linux 2.6.15-rc5: multiuser scheduling trouble Message-ID: <20051210162759.GA15986@aitel.hist.no> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.11 From: Helge Hafting Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1806 Lines: 36 2.6.15-rc5 (and earlier 2.6 kernels) seems to have a slight scheduling problem, with some starvation at a load of only 2. All it takes is two users with separate X desktops. User one plays flash games using firefox. The ill-designed flash stuff typically means that his Xorg and firefox divides the cpu 100% between them. So I expect that I, as user two, should notice some slowness. I should get only 1/2 - 1/3 cpu. But I get periods of starvation. Logging in takes a long time, bringing iup icewm takes 15s instead of 2, each xterm takes a long time to start. They are usually instantaneous. Tha machine is unsuitable for work in this mode. Knowing the root password I renices his Xorg and firefox by 10, and then everything is fine. His games are still ok, and my xterms are snappy again. I have tried no preempt, voluntary preempt, and preemptible kernel. It doesn't make a difference. This is an amd64 kernel on an opteron 244 (1800MHz). Everyhting is 64-bit except firefox+flash which is 32-bit. Perhaps the way flash games work, with lots of communication with the xserver, makes them get "io boost" even though they are cpu hogs. I still think my xterm (or whatever I am starting up) should get its fair third of the cpu though, (with firefox and xorg hogging one third each too.) Even a "600MHz opteron" ought to do better than this. The machine isn't trashing, it is hardly touching swap. (512M memory, and swpd=16 according to vmstat) The paging-in of a starting executable shouldn't be affected much by the cpu load? 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/