From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932267AbXCRKr1 (ORCPT ); Sun, 18 Mar 2007 06:47:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932286AbXCRKr1 (ORCPT ); Sun, 18 Mar 2007 06:47:27 -0400 Received: from smtp15.wxs.nl ([195.121.247.6]:55291 "EHLO smtp15.wxs.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932267AbXCRKr0 (ORCPT ); Sun, 18 Mar 2007 06:47:26 -0400 Date: Sun, 18 Mar 2007 11:50:36 +0100 From: jos poortvliet X-Face: $0>4o"Xx2u2q(Tx!D+6~yPc{ZhEfnQnu:/nthh%Kr%f$aiATk$xjx^X4admsd*)=?utf-8?q?IZz=3A=5FkT=0A=09=7CurITP!=2E?=)L`*)Vw@4\@6>#r;3xSPW`,~C9vb`W/s]}Gq]b!o_/+(lJ:b)=?utf-8?q?T0=26KCLMGvG=7CS=5E=0A=09z=7B=5C=2E7EtehxhFQE=27eYSsir/=7CtQ?= =?utf-8?q?j=23rWQe4o?=>WC>_R To: ck@vds.kolivas.org Cc: Con Kolivas , Al Boldi , linux-kernel@vger.kernel.org Message-id: <200703181150.40059.jos@mijnkamer.nl> MIME-version: 1.0 Content-type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary=nextPart1202439.q3B4AlMpBk Content-transfer-encoding: 7bit User-Agent: KMail/1.9.6 References: <200703042335.26785.a1426z@gawab.com> <200703121426.00854.a1426z@gawab.com> <200703122352.51257.kernel@kolivas.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org --nextPart1202439.q3B4AlMpBk Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Op Sunday 18 March 2007, schreef Con Kolivas: > On Monday 12 March 2007 22:26, Al Boldi wrote: > > Con Kolivas wrote: > > > On Monday 12 March 2007 15:42, Al Boldi wrote: > > > > Con Kolivas wrote: > > > > > On Monday 12 March 2007 08:52, Con Kolivas wrote: > > > > > > And thank you! I think I know what's going on now. I think each > > > > > > rotation is followed by another rotation before the higher > > > > > > priority task is getting a look in in schedule() to even get > > > > > > quota and add it to the runqueue quota. I'll try a simple change > > > > > > to see if that helps. Patch coming up shortly. > > > > > > > > > > Can you try the following patch and see if it helps. There's also > > > > > one minor preemption logic fix in there that I'm planning on > > > > > including. Thanks! > > > > > > > > Applied on top of v0.28 mainline, and there is no difference. > > > > > > > > What's it look like on your machine? > > > > > > The higher priority one always get 6-7ms whereas the lower priority o= ne > > > runs 6-7ms and then one larger perfectly bound expiration amount. > > > Basically exactly as I'd expect. The higher priority task gets > > > precisely RR_INTERVAL maximum latency whereas the lower priority task > > > gets RR_INTERVAL min and full expiration (according to the virtual > > > deadline) as a maximum. That's exactly how I intend it to work. Yes I > > > realise that the max latency ends up being longer intermittently on t= he > > > niced task but that's -in my opinion- perfectly fine as a compromise = to > > > ensure the nice 0 one always gets low latency. > > > > I think, it should be possible to spread this max expiration latency > > across the rotation, should it not? > > There is a way that I toyed with of creating maps of slots to use for each > different priority, but it broke the O(1) nature of the virtual deadline > management. Minimising algorithmic complexity seemed more important to > maintain than getting slightly better latency spreads for niced tasks. It > also appeared to be less cache friendly in design. I could certainly try > and implement it but how much importance are we to place on latency of > niced tasks? Are you aware of any usage scenario where latency sensitive > tasks are ever significantly niced in the real world? I do always nice down heavy games, it makes them more smooth... =2D-=20 Disclaimer: Alles wat ik doe denk en zeg is gebaseerd op het wereldbeeld wat ik nu heb.= =20 Ik ben niet verantwoordelijk voor wijzigingen van de wereld, of het beeld w= at=20 ik daarvan heb, noch voor de daaruit voortvloeiende gedragingen van mezelf.= =20 Alles wat ik zeg is aardig bedoeld, tenzij expliciet vermeld. --nextPart1202439.q3B4AlMpBk Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (GNU/Linux) iD8DBQBF/Rl8+wgQ1AD35iwRAsPLAKDUZdEvS5AIie3yTRCwatqGfiKqhQCgt3KY iqTtD9f2JEfQgiTynaD4ytQ= =FRzi -----END PGP SIGNATURE----- --nextPart1202439.q3B4AlMpBk--