From owner-freebsd-smp Fri Nov 5 11: 3: 2 1999 Delivered-To: freebsd-smp@freebsd.org Received: from megadodo.segNET.COM (megadodo.segNET.COM [206.34.181.3]) by hub.freebsd.org (Postfix) with ESMTP id 86B3614BEA for ; Fri, 5 Nov 1999 11:02:58 -0800 (PST) (envelope-from adams@digitalspark.net) Received: from nightfall.digitalspark.net (arc0a131.bf.sover.net [209.198.85.131]) by megadodo.segNET.COM (8.9.1a/8.8.5) with ESMTP id NAA20743; Fri, 5 Nov 1999 13:54:51 -0500 (EST) Date: Fri, 5 Nov 1999 13:54:53 +0000 (GMT) From: Adam Strohl To: "Rodney W. Grimes" Cc: "Eric J. Schwertfeger" , "Daniel O'Connor" , Darryl Okahata , freebsd-smp@FreeBSD.ORG Subject: Re: Dual Celeron + FreeBSD? In-Reply-To: <199911051829.KAA57885@gndrsh.dnsmgr.net> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-smp@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org I Agree totaly with this, disk is THE choke point for make world for my SMP system, must ... resist .. urge ... to ... buy ... SCSI ... hardware. :) - ----( Adam Strohl )------------------------------------------------ - - UNIX Operations/Systems http://www.digitalspark.net - - adams (at) digitalspark.net xxx.xxx.xxxx xxxxx - - ----------------------------------------( DigitalSpark.NET )------- - On Fri, 5 Nov 1999, Rodney W. Grimes wrote: > > On Thu, 4 Nov 1999, Adam Strohl wrote: > > > > > In the real world the 1/2 the cache at 2x the speed makes all of JACK > > > in performance difference from the "real" PIIs. It rocks. > > > > I agree for the most part, on single-processor machines, though it's > > actually a quarter the cache. The reduced, faster cache causes a single > > celeron to be more memory-bandwidth sensitive. An SMP machine, however, > > has two CPUs contending for the same bandwidth, and for some processes, > > that can be fatal. > > > > I've done make buildworld's on both my dual Celeron and my dual PPro (the > > ones with 512K cache). The difference between single and dual celeron is > > minimal, about 10%. On the dual PPro machine, the speed improvement, > > using the same disk subsystem, was 80%. Yes, on processes that aren't > > memory intensive, dual Celerons rock. In fact, on most things, I see > > closer to 40-50% improvement with dual Celerons, the make buildworld is > > rather memory intensive. > > Actually make buildworld is disk intensive... SMP plain out does not > seem to help it much, unless of course you run a non-standard make > world with -pipe, which then does make the memory bandwidth demand > higher, and if both sides of the pipe just happen to get split accross > 2 processors it causes the small cache to be ineffective and the memory > system to be a major stall point. > > Raid 1 (mirroring) with 3 disk drives tends to help it more than anything... > single or dual processor. Or properly splitting /usr/src, /usr/obj and > ${DESTDIR} to 3 spindles does wonders on any type of cpu, even an old > Pentium 100 sees a big improvement... > > -- > Rod Grimes - KD7CAX @ CN85sl - (RWG25) rgrimes@gndrsh.dnsmgr.net > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-smp" in the body of the message > > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-smp" in the body of the message