Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261269AbUCCXq7 (ORCPT ); Wed, 3 Mar 2004 18:46:59 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261258AbUCCXq7 (ORCPT ); Wed, 3 Mar 2004 18:46:59 -0500 Received: from alt.aurema.com ([203.217.18.57]:11174 "EHLO smtp.sw.oz.au") by vger.kernel.org with ESMTP id S261295AbUCCXqr (ORCPT ); Wed, 3 Mar 2004 18:46:47 -0500 Message-ID: <40466E56.5070801@aurema.com> Date: Thu, 04 Mar 2004 10:46:30 +1100 From: Peter Williams Organization: Aurema Pty Ltd User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030624 Netscape/7.1 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Andi Kleen CC: linux-kernel@vger.kernel.org, johnl@aurema.com Subject: Re: [RFC][PATCH] O(1) Entitlement Based Scheduler References: <40426E1C.8010806@aurema.com.suse.lists.linux.kernel> <404554D8.5040800@aurema.com> <20040303101336.GC8008@wotan.suse.de> In-Reply-To: <20040303101336.GC8008@wotan.suse.de> 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: 2906 Lines: 64 Andi Kleen wrote: > On Wed, Mar 03, 2004 at 02:45:28PM +1100, Peter Williams wrote: > >>Andi Kleen wrote: >> >>>Peter Williams writes: >>> >>>One comment on the patches: could you remove the zillions of numerical >>>Kconfig >>>options and just make them sysctls? I don't think it makes any sense >>>to require a reboot to change any of that. And the user is unlikely >>>to have much idea yet on what he wants on them while configuring. >> >>The default initial values should be fine and the default configuration >>allows the scheduling tuning parameters (i.e. half life and time slice >> ) to be changed on a running system via the /proc file system. >>These are mainly there so that different settings can be used with >>various benchmarks to determine what are the best settings for various >>types of loads. If good default values that work well for a wide >>variety of load types can be found as a result of these experiments then >>these parameters may be made constants in the code. If not they >>probably should be made settable via system calls rather than via /proc >>as you suggest. > > > No doubt that there are different settings that make sense > for different workloads. But there is no reason one has to recompile > to set them - it's much nicer to just run a script at boot time to set > them, instead of recompiling/rebooting. This will also make benchmarking > much easier, because you can just write a script that sets the > various parameters, runs workloads, sets other parameters, runs > workload again etc. Requiring a recompile and reboot makes this > much harder. As I said (with the full patch) these values can be set via /proc on a running system so there's no need for a recompile and reboot. > > Also I suspect most people who are not heavily into scheduling > theory will go with the defaults at compile time, so it's important > that they already work well. > > And consider it from the side of a standard distribution: users > don't normally recompile their kernels there, so everything that > makes sense to be tunable should be settable without recompiling. > > IMHO CONFIG_* should not be used for anything except for kernel binary > size tuning and possible compiler tuning. Yes, once this patch has stabilised we will probably remove some (or all) of the configuration variables. Peter -- Dr Peter Williams, Chief Scientist peterw@aurema.com Aurema Pty Limited Tel:+61 2 9698 2322 PO Box 305, Strawberry Hills NSW 2012, Australia Fax:+61 2 9699 9174 79 Myrtle Street, Chippendale NSW 2008, Australia http://www.aurema.com - 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/