From owner-freebsd-hackers@FreeBSD.ORG Wed Sep 22 13:41:18 2010 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 673291065670; Wed, 22 Sep 2010 13:41:18 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from cyrus.watson.org (cyrus.watson.org [65.122.17.42]) by mx1.freebsd.org (Postfix) with ESMTP id 34DFF8FC08; Wed, 22 Sep 2010 13:41:18 +0000 (UTC) Received: from bigwig.baldwin.cx (66.111.2.69.static.nyinternet.net [66.111.2.69]) by cyrus.watson.org (Postfix) with ESMTPSA id B782E46B17; Wed, 22 Sep 2010 09:41:17 -0400 (EDT) Received: from jhbbsd.localnet (smtp.hudson-trading.com [209.249.190.9]) by bigwig.baldwin.cx (Postfix) with ESMTPSA id 46D668A04E; Wed, 22 Sep 2010 09:41:14 -0400 (EDT) From: John Baldwin To: freebsd-current@freebsd.org Date: Wed, 22 Sep 2010 09:37:12 -0400 User-Agent: KMail/1.13.5 (FreeBSD/7.3-CBSD-20100819; KDE/4.4.5; amd64; ; ) References: <4C99DC48.1020208@FreeBSD.org> In-Reply-To: <4C99DC48.1020208@FreeBSD.org> MIME-Version: 1.0 Content-Type: Text/Plain; charset="koi8-u" Content-Transfer-Encoding: 7bit Message-Id: <201009220937.13155.jhb@freebsd.org> X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.0.1 (bigwig.baldwin.cx); Wed, 22 Sep 2010 09:41:15 -0400 (EDT) X-Virus-Scanned: clamav-milter 0.95.1 at bigwig.baldwin.cx X-Virus-Status: Clean X-Spam-Status: No, score=-2.6 required=4.2 tests=AWL,BAYES_00 autolearn=ham version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on bigwig.baldwin.cx Cc: Maxim Sobolev , Jeff Roberson , "current@freebsd.org" , FreeBSD Hackers Subject: Re: Bumping MAXCPU on amd64? 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: Wed, 22 Sep 2010 13:41:18 -0000 On Wednesday, September 22, 2010 6:36:56 am Maxim Sobolev wrote: > Hi, > > Is there any reason to keep MAXCPU at 16 in the default kernel config? > There are quite few servers on the market today that have 24 or even 32 > physical cores. With hyper-threading this can even go as high as 48 or > 64 virtual cpus. People who buy such hardware might get very > disappointed finding out that the FreeBSD is not going to use such > hardware to its full potential. > > Does anybody object if I'd bump MAXCPU to 32, which is still low but > might me more reasonable default these days, or at least make it an > kernel configuration option documented in the NOTES? ? % grep MAXCPU ~/work/freebsd/svn/head/sys/amd64/include/param.h #define MAXCPU 32 #define MAXCPU 1 In fact: % grep MAXCPU ~/work/freebsd/svn/stable/8/sys/amd64/include/param.h #define MAXCPU 32 #define MAXCPU 1 Unfortunately this can't be MFC'd to 7 as it would destroy the ABI for existing klds. -- John Baldwin