From owner-freebsd-questions Fri Jul 12 0:47:38 2002 Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.FreeBSD.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 7D55E37B400 for ; Fri, 12 Jul 2002 00:47:33 -0700 (PDT) Received: from andrsn.stanford.edu (andrsn.Stanford.EDU [171.66.112.163]) by mx1.FreeBSD.org (Postfix) with ESMTP id B729243E6E for ; Fri, 12 Jul 2002 00:47:32 -0700 (PDT) (envelope-from andrsn@andrsn.stanford.edu) Received: from localhost (localhost.stanford.edu [127.0.0.1]) by andrsn.stanford.edu (8.11.6/8.11.6) with ESMTP id g6C7ihw83997; Fri, 12 Jul 2002 00:44:43 -0700 (PDT) (envelope-from andrsn@andrsn.stanford.edu) Date: Fri, 12 Jul 2002 00:44:43 -0700 (PDT) From: Annelise Anderson To: Steve Wingate Cc: freebsd-questions@freebsd.org Subject: Re: Using Memory Disks to Build World In-Reply-To: <1026398517.282.18.camel@daemon.velosystems.net> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On 11 Jul 2002, Steve Wingate wrote: > On Thu, 2002-07-11 at 00:03, Annelise Anderson wrote: > > I would like to do a make world with /usr/obj and /usr/src > > on memory disks (this system has 2GB RAM, so I figure 512MB > > for each ought to be enough). This is a 4.6-stable system. > > > > I created some md devices in /dev, but can't make > > mount_mfs work with something like > > mount_mfs -s 1048576 /dev/md0 /usr/src > > or mount_mfs -s 1048576 /dev/md0s1 /usr/src > > > What you want is: > mount_mfs -s 900000 /dev/ad0s1b /usr/obj > ( for a 450MB'ish MFS) > > assuming that device is your swap. Incidentally I tried mounting obj & > src into MFS on this box then did 'make -jn world' with n going from 2 > to 16 and they were ALL slower than the simple 'make world' with > everything on disk. Since I can make world in 25 minutes already it > wasn't the end of the world, how I was sure this would've cut it to < 20 > minutes at least. > Thanks, that worked. Mine was a few minutes faster (just under 27 minutes) instead of 29 or so on the buildworld, where I used -j16. Peter Wemm said in an informal forum that the bottleneck is the "make" command, which has to start running a process before it will (if I have this right) begin another process. So with fast disks and softupdates, it doesn't help much use the memory file system. But heh, it was fun, and I learned how to do it, thanks to you and others. :) Annelise -- Annelise Anderson Author of: FreeBSD: An Open-Source Operating System for Your PC Available from: BSDmall.com and amazon.com Book Website: http://www.bittreepress.com/FreeBSD/introbook/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message