From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261187AbUCPLs0 (ORCPT ); Tue, 16 Mar 2004 06:48:26 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261526AbUCPLs0 (ORCPT ); Tue, 16 Mar 2004 06:48:26 -0500 Received: from ns.suse.de ([195.135.220.2]:1701 "EHLO Cantor.suse.de") by vger.kernel.org with ESMTP id S261187AbUCPLsX (ORCPT ); Tue, 16 Mar 2004 06:48:23 -0500 Date: Tue, 16 Mar 2004 12:48:20 +0100 From: Kurt Garloff To: Nick Piggin Cc: Con Kolivas , Linux kernel list Subject: Re: bonus inheritance Message-ID: <20040316114820.GM4452@tpkurt.garloff.de> Mail-Followup-To: Kurt Garloff , Nick Piggin , Con Kolivas , Linux kernel list References: <20040315225459.GY4452@tpkurt.garloff.de> <405696A9.3060304@cyberone.com.au> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="6JKsAUbrJhuSllgx" Content-Disposition: inline In-Reply-To: <405696A9.3060304@cyberone.com.au> X-Operating-System: Linux 2.6.4-1-KG i686 X-PGP-Info: on http://www.garloff.de/kurt/mykeys.pgp X-PGP-Key: 1024D/1C98774E, 1024R/CEFC9215 Organization: SUSE/Novell User-Agent: Mutt/1.5.6i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org --6JKsAUbrJhuSllgx Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi Nick, On Tue, Mar 16, 2004 at 04:54:49PM +1100, Nick Piggin wrote: > Does it help any actual interactivity problem? Unfortunately > practically any you make to the scheduler is bound to make > things worse for at least one person, so it is difficult to > just test things out. Well, the interactivity problems existed with O(1) in 2.4. The 50% penalty hurt freshly started processes a lot. To fix this, the penalty has been set to 95 (5% penalty) in 2.6. I believe it's cleaner to draw the bonus towards the average=20 and inherit a percentage, and thus I set a inheritance percentage=20 of 50 in 2.4. It was successful in 2.4. In a measurable way. In 2.6, it likely will not make a big difference as with giving=20 95% of the bonus, you don't change much ... So it's more a question of have the concept in there which is clearer. More a theoretical thing. Assuming that with 95% chance your child has the same character w.r.t. to interactiveness is rather high. It will be very hard to measure 80% inheritance to 95% penalty=20 as for the most important case (starting a process from a shell),=20 the results are almost the same. The fact that we are more likely to start new processes towards=20 the center in our bonus scale certainly makes it faster for the scheduler to put them in the right category, so there should be some benefit w.r.t. interactiveness. However, those are not easy=20 to measure :-( I'll see whether we can get some benchmarks anyway. Regards, --=20 Kurt Garloff Cologne, DE=20 SUSE LINUX AG, Nuernberg, DE SUSE Labs (Head) --6JKsAUbrJhuSllgx Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.3 (GNU/Linux) iD8DBQFAVumExmLh6hyYd04RAmePAJ0StpcH+fcq8FrJvTyCSicAHzrclwCeIxz2 iRH66W03td0RD9xVkrVMBaM= =WnZr -----END PGP SIGNATURE----- --6JKsAUbrJhuSllgx--