Date: Fri, 12 Jul 2002 00:44:43 -0700 (PDT) From: Annelise Anderson <andrsn@andrsn.stanford.edu> To: Steve Wingate <steve@velosystems.net> Cc: freebsd-questions@freebsd.org Subject: Re: Using Memory Disks to Build World Message-ID: <Pine.BSF.4.10.10207120039330.83956-100000@andrsn.stanford.edu> In-Reply-To: <1026398517.282.18.camel@daemon.velosystems.net>
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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
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