From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S272442AbTHEFQV (ORCPT ); Tue, 5 Aug 2003 01:16:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S272443AbTHEFQV (ORCPT ); Tue, 5 Aug 2003 01:16:21 -0400 Received: from c210-49-248-224.thoms1.vic.optusnet.com.au ([210.49.248.224]:16540 "EHLO mail.kolivas.org") by vger.kernel.org with ESMTP id S272442AbTHEFQO (ORCPT ); Tue, 5 Aug 2003 01:16:14 -0400 Message-ID: <1060060568.3f2f3d989683f@kolivas.org> Date: Tue, 5 Aug 2003 15:16:08 +1000 From: Con Kolivas To: Nick Piggin Cc: linux kernel mailing list , Andrew Morton , Ingo Molnar , Felipe Alfaro Solana Subject: Re: [PATCH] O13int for interactivity References: <200308050207.18096.kernel@kolivas.org> <200308051220.04779.kernel@kolivas.org> <3F2F149F.1020201@cyberone.com.au> <200308051318.47464.kernel@kolivas.org> <3F2F2517.7080507@cyberone.com.au> <1060059844.3f2f3ac46e2f2@kolivas.org> <3F2F3CC6.2060307@cyberone.com.au> In-Reply-To: <3F2F3CC6.2060307@cyberone.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT User-Agent: Internet Messaging Program (IMP) 3.2.1 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Quoting Nick Piggin : > Con Kolivas wrote: > > >Quoting Nick Piggin : > > > > > >> > >>Con Kolivas wrote: > >> > >> > >>>On Tue, 5 Aug 2003 12:21, Nick Piggin wrote: > >>> > >>> > >>>>No, this still special-cases the uninterruptible sleep. Why is this > >>>>needed? What is being worked around? There is probably a way to > >>>>attack the cause of the problem. > >>>> > >>>> > >>>Footnote: I was thinking of using this to also _elevate_ the dynamic > >>> > >>priority > >> > >>>of tasks waking from interruptible sleep as well which may help > throughput. > >>> > >>> > >>Con, an uninterruptible sleep is one which is not be woken by a signal, > >>an interruptible sleep is one which is. There is no other connotation. > >>What happens when read/write syscalls are changed to be interruptible? > >>I'm not saying this will happen... but come to think of it, NFS probably > >>has interruptible read/write. > >> > >>In short: make the same policy for an interruptible and an uninterruptible > >>sleep. > >> > > > >That's the policy that has always existed... > > > >Interesting that I have only seen the desired effect and haven't noticed any > > >side effect from this change so far. I'll keep experimenting as much as > >possible (as if I wasn't going to) and see what the testers find as well. > > > > Oh, I'm not saying that your change is outright wrong, on the contrary I'd > say you have a better feel for what is needed than I do, but if you are > finding > that the uninterruptible sleep case needs some tweaking then the same tweak > should be applied to all sleep cases. If there really is a difference, > then its > just a fluke that the sleep paths in question use the type of sleep you are > testing for, and nothing more profound than that. Ah I see. It was from my observations of the behaviour of tasks in D that found it was the period spent in D that was leading to unfairness. The same tweak can't be applied to the rest of the sleeps because that inactivates everything. So it is a fluke that the thing I'm trying to penalise is what tasks in uninterruptible sleep do, but it is by backward observation of D tasks, not random chance. Con