From owner-freebsd-hackers Mon Feb 12 6:30:47 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from flood.ping.uio.no (flood.ping.uio.no [129.240.78.31]) by hub.freebsd.org (Postfix) with ESMTP id 7C7C437B401 for ; Mon, 12 Feb 2001 06:30:42 -0800 (PST) Received: (from des@localhost) by flood.ping.uio.no (8.9.3/8.9.3) id PAA89380; Mon, 12 Feb 2001 15:29:18 +0100 (CET) (envelope-from des@ofug.org) X-URL: http://www.ofug.org/~des/ X-Disclaimer: The views expressed in this message do not necessarily coincide with those of any organisation or company with which I am or have been affiliated. To: Danny Braniss Cc: Matt Dillon , freebsd-hackers@FreeBSD.ORG Subject: Re: soft updates performance References: From: Dag-Erling Smorgrav Date: 12 Feb 2001 15:29:17 +0100 In-Reply-To: Danny Braniss's message of "Sun, 11 Feb 2001 13:40:06 +0200" Message-ID: Lines: 20 User-Agent: Gnus/5.0802 (Gnus v5.8.2) Emacs/20.4 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Danny Braniss writes: > i've been doing some experiments with vinum, and doing a make buildworld > (with obj on the same vinum) > without soft-updates ~ 1 hour > with soft-updates ~ 40 minutes > which is a bit better than 3% :-) > > what i can't figure out is why -j 4 didn't make any difference. Because your I/O system is already saturated. The point with -jNN is that one job can run while another is waiting for I/O to complete and vice versa, but as your CPU gets faster the time spent actually compiling etc. becomes insignificant next to the time spent doing I/O, and if you're already doing I/O as fast as you can there's no room for improvement. On a machine with a slower CPU or a faster I/O system, you'd see improvement. DES -- Dag-Erling Smorgrav - des@ofug.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message