From owner-freebsd-smp Sun Sep 14 20:53:14 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id UAA24853 for smp-outgoing; Sun, 14 Sep 1997 20:53:14 -0700 (PDT) Received: from implode.root.com (implode.root.com [198.145.90.17]) by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id UAA24848 for ; Sun, 14 Sep 1997 20:53:09 -0700 (PDT) Received: from implode.root.com (localhost [127.0.0.1]) by implode.root.com (8.8.5/8.8.5) with ESMTP id UAA24481; Sun, 14 Sep 1997 20:55:03 -0700 (PDT) Message-Id: <199709150355.UAA24481@implode.root.com> To: Simon Shapiro cc: Terry Lambert , missmanp@milo.cfw.com, freebsd-smp@freebsd.org Subject: Re: SMP in FreeBSD 3.x.x In-reply-to: Your message of "Sun, 14 Sep 1997 13:03:59 PDT." From: David Greenman Reply-To: dg@root.com Date: Sun, 14 Sep 1997 20:55:03 -0700 Sender: owner-freebsd-smp@freebsd.org X-Loop: FreeBSD.org Precedence: bulk >:-) was that aroud 30 processors is where scalability will fall off. We >used Dynix + Oracle for O/S application model. Processor was Pentium. If >I remember correctly, the P6-200 has worse instructions/memory/IO bandwidth >ratios than Pentiums-66 does. That led to the conclusion that we will not >grow beyond 30 either. I will not go into what the initial P7 was supposed This contradicts a paper that was given at a recent Usenix-sponsored conference that shows that the amount of main memory traffic in P6 systems is *dramatically* reduced over Pentium systems. I forget the exact ratio, but it is something like 1/5th. This is entirely due to the superior cache architecture of the P6. -DG David Greenman Core-team/Principal Architect, The FreeBSD Project