From owner-freebsd-current Wed Dec 10 18:18:17 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id SAA18757 for current-outgoing; Wed, 10 Dec 1997 18:18:17 -0800 (PST) (envelope-from owner-freebsd-current) Received: from zippy.dyn.ml.org (spain-19.ppp.hooked.net [206.169.228.19]) by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id SAA18736 for ; Wed, 10 Dec 1997 18:18:11 -0800 (PST) (envelope-from garbanzo@hooked.net) Received: from localhost (garbanzo@localhost) by zippy.dyn.ml.org (8.8.8/8.8.7) with SMTP id SAA02689; Wed, 10 Dec 1997 18:19:06 -0800 (PST) X-Authentication-Warning: zippy.dyn.ml.org: garbanzo owned process doing -bs Date: Wed, 10 Dec 1997 18:19:05 -0800 (PST) From: Alex X-Sender: garbanzo@zippy.dyn.ml.org To: Jason Evans cc: Steve Passe , current Subject: Re: -current, goliath, smp -- problems In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-current@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk On Tue, 9 Dec 1997, Jason Evans wrote: > Well, I don't know that I would necessarily expect this to be as cool as > it sounds. I'm not an expert on this by any means, but I've > repeatedly heard the following: > > Tightly coupled MP machines work well until memory bandwidth becomes a > bottleneck. Last I heard, the memory bandwidth on Intel-based machines is > in the neighborhood of 500 MB/sec, which is enough to feed 4 processors, > but quite inadequate for 8. So, even though there are twice as many > processors, the performance gain is not impressive. > > If there's anyone else out there that knows any better, please correct me. > =) Who knows, HP may have (and hopefully did) use a different sort of memory bus, and tweaked whatever else might not be up to snuff for 8cpus. - alex