From owner-freebsd-stable@FreeBSD.ORG Mon Dec 12 20:25:48 2011 Return-Path: Delivered-To: stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 08D85106564A for ; Mon, 12 Dec 2011 20:25:48 +0000 (UTC) (envelope-from wollman@hergotha.csail.mit.edu) Received: from hergotha.csail.mit.edu (wollman-1-pt.tunnel.tserv4.nyc4.ipv6.he.net [IPv6:2001:470:1f06:ccb::2]) by mx1.freebsd.org (Postfix) with ESMTP id B26208FC0C for ; Mon, 12 Dec 2011 20:25:47 +0000 (UTC) Received: from hergotha.csail.mit.edu (localhost [127.0.0.1]) by hergotha.csail.mit.edu (8.14.4/8.14.4) with ESMTP id pBCKPgkO044580; Mon, 12 Dec 2011 15:25:43 -0500 (EST) (envelope-from wollman@hergotha.csail.mit.edu) Received: (from wollman@localhost) by hergotha.csail.mit.edu (8.14.4/8.14.4/Submit) id pBCKPgtB044579; Mon, 12 Dec 2011 15:25:42 -0500 (EST) (envelope-from wollman) Date: Mon, 12 Dec 2011 15:25:42 -0500 (EST) From: Garrett Wollman Message-Id: <201112122025.pBCKPgtB044579@hergotha.csail.mit.edu> To: bruce@cran.org.uk X-Newsgroups: mit.lcs.mail.freebsd-stable In-Reply-To: <4EE6595C.3080608@cran.org.uk> References: <4EE1EAFE.3070408@m5p.com> <4EE22421.9060707@gmail.com> <4EE6060D.5060201@mail.zedat.fu-berlin.de> <20111212155159.GB73597@troutmask.apl.washington.edu> <20198.21654.915449.536365@hergotha.csail.mit.edu> Organization: none X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.7 (hergotha.csail.mit.edu [127.0.0.1]); Mon, 12 Dec 2011 15:25:43 -0500 (EST) X-Spam-Status: No, score=-1.0 required=5.0 tests=ALL_TRUSTED autolearn=disabled version=3.3.2 X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on hergotha.csail.mit.edu Cc: stable@freebsd.org Subject: Re: SCHED_ULE should not be the default X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 12 Dec 2011 20:25:48 -0000 In article <4EE6595C.3080608@cran.org.uk>, bruce@cran.org.uk writes: >On 12/12/2011 19:23, Garrett Wollman wrote: >> Where do you get that idea? I've never seen any evidence for this >> proposition (although the claim is repeated often enough). What are >> the specific circumstances that make this useful? Where did the >> number come from? > >It's just something I've heard repeated, and people claiming that >setting it improves performance. > >This explains how the value 224 was obtained: >http://lists.freebsd.org/pipermail/freebsd-stable/2010-September/058686.html Not so far as I can see. The message does suggest that it helps if you are running a CPU-hog GUI, which seems plausible to me, but doesn't justify making it the default -- particularly when the setting is undocumented. (It appears to control how CPU-bound a process can be and still preempt another even more CPU-bound process, so using this as a "desktop performance" "fix" looks doubly wrong.) -GAWollman