Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753791Ab0KSNUl (ORCPT ); Fri, 19 Nov 2010 08:20:41 -0500 Received: from mail.openrapids.net ([64.15.138.104]:44094 "EHLO blackscsi.openrapids.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752393Ab0KSNUk (ORCPT ); Fri, 19 Nov 2010 08:20:40 -0500 Date: Fri, 19 Nov 2010 08:20:37 -0500 From: Mathieu Desnoyers To: Peter Zijlstra Cc: Samuel Thibault , Mike Galbraith , Hans-Peter Jansen , linux-kernel@vger.kernel.org, Lennart Poettering , Linus Torvalds , david@lang.hm, Dhaval Giani , Vivek Goyal , Oleg Nesterov , Markus Trippelsdorf , Ingo Molnar , Balbir Singh Subject: Re: [RFC/RFT PATCH v3] sched: automated per tty task groups Message-ID: <20101119132037.GA18589@Krystal> References: <20101116211431.GA15211@tango.0pointer.de> <201011182333.48281.hpj@urpla.net> <20101118231218.GX6024@const.famille.thibault.fr> <1290123351.18039.49.camel@maggy.simson.net> <20101118234339.GA6024@const.famille.thibault.fr> <1290167376.2109.1553.camel@laptop> <1290169178.2109.1573.camel@laptop> <20101119125548.GC24411@Krystal> <1290171648.2109.1580.camel@laptop> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1290171648.2109.1580.camel@laptop> X-Editor: vi X-Info: http://www.efficios.com X-Operating-System: Linux/2.6.26-2-686 (i686) X-Uptime: 08:13:48 up 57 days, 17:15, 3 users, load average: 1.09, 1.22, 1.19 User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1291 Lines: 34 * Peter Zijlstra (peterz@infradead.org) wrote: > On Fri, 2010-11-19 at 07:55 -0500, Mathieu Desnoyers wrote: [...] > > Yep, this looks like one of these perpetual throughput vs latency trade-offs. > > > Trade-off sure, throughput vs latency only in a specific use-case, its > more a feature vs cost thing, just like all them trace people want lower > cost tracing but want more features at the same time.. Yep, agreed for "feature vs cost", given that the kind of latency that is fixed in this case really boils down to a sluggish system under a relatively common workload -- so making this work might be called a "feature". ;) FWIW, about tracing, well, we should distinguish between features that add cost to the fast-path and slow-path only. But I really don't care anymore, since Ingo, Linus, Thomas and yourself made it very clear that you don't care. So let's not even start this discussion -- it's going nowhere. Thanks, Mathieu -- Mathieu Desnoyers Operating System Efficiency R&D Consultant EfficiOS Inc. http://www.efficios.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/