From owner-freebsd-hackers@FreeBSD.ORG Tue Apr 10 20:05:24 2012 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id A8C0C1065670 for ; Tue, 10 Apr 2012 20:05:24 +0000 (UTC) (envelope-from mwm@mired.org) Received: from mail-iy0-f182.google.com (mail-iy0-f182.google.com [209.85.210.182]) by mx1.freebsd.org (Postfix) with ESMTP id 53EC58FC0C for ; Tue, 10 Apr 2012 20:05:24 +0000 (UTC) Received: by iahk25 with SMTP id k25so266740iah.13 for ; Tue, 10 Apr 2012 13:05:18 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=date:from:to:subject:message-id:in-reply-to:references:organization :x-mailer:face:mime-version:content-type:content-transfer-encoding :x-gm-message-state; bh=c1x0YgCC9SRzIEJq0sU+SsWXLQjoj61Q/AdaghdsQcU=; b=YwUHIdSIso6blsTSTcsQihd8iVl+9zoZEGbdcMeBb7c7k/iOg+Jvo2SRadd2P84rxC Z+wfKORQjuxEacB/6TF7Yii06UmB5dX8ca8BFeJVXxcm5NPM0cUIatZSVl+ORFu3KQKB dSOR6glsnTVzptwyKoMOe3N6CwYUzwfwbllaihKlRkwWP+DGO7SoMY4SmtyKbQNPGMY7 fXXZAO2hcBKeNCnT6U/q01SMh6iJiDLpAfR0rI+xzfOUE2dF//QSG7p3ZuyKmDn9g/tJ l34IygXUQNT1w08hzlcPgLx1Md/VQZsf4EIX+dqbrDG3zbmY6QLkKSyqALXQbuRIh3BK u/pg== Received: by 10.50.192.228 with SMTP id hj4mr3614920igc.72.1334088318647; Tue, 10 Apr 2012 13:05:18 -0700 (PDT) Received: from bhuda.mired.org (74-140-201-117.dhcp.insightbb.com. [74.140.201.117]) by mx.google.com with ESMTPS id re5sm21753553igb.0.2012.04.10.13.05.17 (version=TLSv1/SSLv3 cipher=OTHER); Tue, 10 Apr 2012 13:05:18 -0700 (PDT) Date: Tue, 10 Apr 2012 16:05:13 -0400 From: Mike Meyer To: freebsd-hackers@freebsd.org Message-ID: <20120410160513.0b322f68@bhuda.mired.org> In-Reply-To: References: <4F2F7B7F.40508@FreeBSD.org> <4F366E8F.9060207@FreeBSD.org> <4F367965.6000602@FreeBSD.org> <4F396B24.5090602@FreeBSD.org> <4F3978BC.6090608@FreeBSD.org> <4F3990EA.1080002@FreeBSD.org> <4F3C0BB9.6050101@FreeBSD.org> <4F3E807A.60103@FreeBSD.org> <4F3E8858.4000001@FreeBSD.org> <4F7DE863.6080607@FreeBSD.org> <4F833F3D.7070106@FreeBSD.org> Organization: Meyer Consulting X-Mailer: Claws Mail 3.8.0 (GTK+ 2.24.6; amd64-portbld-freebsd8.2) Face: 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 Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Gm-Message-State: ALoCoQng007War6WgxQXMJq0pxKUFQWvuuQSwHjaoGne8bSueu2bV8PvpuutSIqhROT5JTqzRp17 Subject: Re: [RFT][patch] Scheduling for HTT and not only X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 10 Apr 2012 20:05:24 -0000 On Tue, 10 Apr 2012 12:58:00 -0400 Arnaud Lacombe wrote: > Let me disagree on your conclusion. If OS A does a task in X seconds, > and OS B does the same task in Y seconds, if Y > X, then OS B is just > not performing good enough. Others have pointed out one problem with this statement. Let me point out another: It ignores the purpose of the system. If you change the task to doing N concurrent versions of the task, and OS A time increases linearly with the number of tasks (say it's time X*N) but OS B stair-steps at the number of processors in the system (i.e. Y*floor(N/P)), then OS A is just not performing good enough. A more concrete example: if OS B spends a couple of microseconds optimizing disk access order and OS A doesn't, then a single process writing to disk on OS A could well run faster than the same on OS B. However, the maximum throughput on OS B as you add process will be higher than it is on OS A. Which one you want will depend on what you're using the system for. http://www.mired.org/ Independent Software developer/SCM consultant, email for more information. O< ascii ribbon campaign - stop html mail - www.asciiribbon.org