From owner-freebsd-current@FreeBSD.ORG Fri Mar 27 18:30:26 2009 Return-Path: Delivered-To: freebsd-current@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id EEC5210656C1; Fri, 27 Mar 2009 18:30:26 +0000 (UTC) (envelope-from scottl@samsco.org) Received: from pooker.samsco.org (pooker.samsco.org [168.103.85.57]) by mx1.freebsd.org (Postfix) with ESMTP id 9B5468FC0C; Fri, 27 Mar 2009 18:30:26 +0000 (UTC) (envelope-from scottl@samsco.org) Received: from phobos.local ([192.168.254.200]) (authenticated bits=0) by pooker.samsco.org (8.14.2/8.14.2) with ESMTP id n2RIUL7v061016; Fri, 27 Mar 2009 12:30:21 -0600 (MDT) (envelope-from scottl@samsco.org) Message-ID: <49CD1B3D.3030103@samsco.org> Date: Fri, 27 Mar 2009 12:30:21 -0600 From: Scott Long User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X; en-US; rv:1.8.1.13) Gecko/20080313 SeaMonkey/1.1.9 MIME-Version: 1.0 To: Robert Watson References: <11609492.9579.1238167614335.JavaMail.root@vms070.mailsrvcs.net> <49CD0405.1060704@samsco.org> In-Reply-To: X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-4.4 required=3.8 tests=ALL_TRUSTED,BAYES_00 autolearn=ham version=3.1.8 X-Spam-Checker-Version: SpamAssassin 3.1.8 (2007-02-13) on pooker.samsco.org Cc: Sergey Babkin , freebsd-hackers@FreeBSD.org, attilio@FreeBSD.org, phk@phk.freebsd.dk, freebsd-current@FreeBSD.org, prashant.vaibhav@gmail.com Subject: Re: Improving the kernel/i386 timecounter performance (GSoC proposal) X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 27 Mar 2009 18:30:28 -0000 Robert Watson wrote: > > On Fri, 27 Mar 2009, Scott Long wrote: > >> I've been talking about this for years. All I need is help with the >> VM magic to create the page on fork. I also want two pages, one >> global for gettimeofday (and any other global data we can think of) >> and one per-process for static data like getpid/getgid. > > FWIW, there are some variations in schemes across OS's -- one extreme is > the Linux approach, which actually exports a mini shared library in ELF > format on the shared page, providing implementations of various services > (such as entering system calls), time stuff, etc. Less extreme are the > shared pages offered on Mac OS X, etc. > Yes, but I'd like to start somewhere, and considering that it's been impossible in _5_ years to get the 30 minutes of Peter or JeffR or JHB time to get the basic VM magic done, I'm keeping my expectations as modest as possible. Scott