From owner-freebsd-current Sun Mar 22 11:45:28 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id LAA18894 for freebsd-current-outgoing; Sun, 22 Mar 1998 11:45:28 -0800 (PST) (envelope-from owner-freebsd-current@FreeBSD.ORG) Received: from sendero.simon-shapiro.org (sendero-fddi.Simon-Shapiro.ORG [206.190.148.2]) by hub.freebsd.org (8.8.8/8.8.8) with SMTP id LAA18886 for ; Sun, 22 Mar 1998 11:45:24 -0800 (PST) (envelope-from shimon@simon-shapiro.org) Received: (qmail 27326 invoked from network); 22 Mar 1998 19:50:51 -0000 Received: from localhost.simon-shapiro.org (HELO sendero-fxp0.simon-shapiro.org) (@127.0.0.1) by localhost.simon-shapiro.org with SMTP; 22 Mar 1998 19:50:51 -0000 Message-ID: X-Mailer: XFMail 1.3-alpha-031798 [p0] on FreeBSD X-Priority: 3 (Normal) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit MIME-Version: 1.0 In-Reply-To: <199803220833.TAA14256@gurney.reilly.home> Date: Sun, 22 Mar 1998 11:50:51 -0800 (PST) Reply-To: shimon@simon-shapiro.org Organization: The Simon Shapiro Foundation From: Simon Shapiro To: Andrew Reilly Subject: Re: Worldstone Continued... Cc: current@FreeBSD.ORG, taob@nbc.netcom.ca Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On 22-Mar-98 Andrew Reilly wrote: > On 21 Mar, Simon Shapiro wrote: >> My very humble opinion is that we are barking up the wrong tree. Disk >> I/O >> is not the limiting factor here. I am looking at disk bandwidth >> utilization of less than 20%. From idle observation, it appears that >> parsing Makefiles is 4-5 times the amount of time it takes to actually >> compile anything. >> >> The curious could take the kernel directory and write a simple script >> to >> compile it without make at all. Tell us the results. > > For the kernel, that's nothing more than the output of make -n. I > think that building a script for make buildworld could be a little > trickier. > > I'm a little surprised that you think that make itself is so > expensive. Simple observation; make clean && make depend && make -j8 in the kernel. Observe the relative time it takes make to prepare what to do, and the time it takes to actually compile it. Another Observation; I can increase disk bandwidth for large compilations (make world, etc.) almost linearly with only minimal gain in overall time. I compiled on RAID-5, RAID-0, with stripe width up to 8 drives, with source and objects on separate arrays. WRITE cache is set to write-back, the system can demonstrate 5-19 MB/Sec for random I/O on small blocks, up to 1740 disk ops/sec. Make buildworld and make -j8buildworld are resulting in 200, 280 disk I/O ops/sec, respectively. CPU utilization is 80% user 70% system (figure this one out :-). I conclude from these numbers that the system is not starved for I/O. There could be one of several explanations: * Make, which is low-I/O consumer, takes inordinate amount of time * Compilations are CPU intensive, more than we think * The current SCSI layer is somehow slow I wish I had the time to port the DPT driver to CAM. This will give us an answer. ---------- Sincerely Yours, Simon Shapiro Shimon@Simon-Shapiro.ORG Voice: 503.799.2313 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message