From owner-freebsd-current@FreeBSD.ORG Mon May 22 18:33:24 2006 Return-Path: X-Original-To: current@freebsd.org Delivered-To: freebsd-current@FreeBSD.ORG Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 8589916A6E2 for ; Mon, 22 May 2006 18:33:24 +0000 (UTC) (envelope-from needacoder@gmail.com) Received: from nf-out-0910.google.com (nf-out-0910.google.com [64.233.182.185]) by mx1.FreeBSD.org (Postfix) with ESMTP id D3C3343D45 for ; Mon, 22 May 2006 18:33:23 +0000 (GMT) (envelope-from needacoder@gmail.com) Received: by nf-out-0910.google.com with SMTP id x29so594778nfb for ; Mon, 22 May 2006 11:33:22 -0700 (PDT) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=sprH+w5dBjdI1BS3ESq4TNjd8Znh4jSLKYowPlYIU0hi620aNQ5QJ8vQSp1x7ps5KL4JKWiHxuOxxQ9aXnNyC1dXgpUJnbCLD4KjZu3cr2m1sJ3Irds7qAsum2J3zC2lYAj8XC5oVzX7RRRGA3ix3UBKf7qxgb7i7J/U+dQPmYQ= Received: by 10.48.219.1 with SMTP id r1mr4042486nfg; Mon, 22 May 2006 11:33:22 -0700 (PDT) Received: by 10.49.75.2 with HTTP; Mon, 22 May 2006 11:33:22 -0700 (PDT) Message-ID: <1e4841eb0605221133s428d9136p3d5f7eff964167f4@mail.gmail.com> Date: Mon, 22 May 2006 14:33:22 -0400 From: "m m" To: "Chad Leigh -- Shire.Net LLC" In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: quoted-printable Content-Disposition: inline References: <1e4841eb0605211854i44c4aa4cm9dfc72506c2232ea@mail.gmail.com> X-Mailman-Approved-At: Mon, 22 May 2006 19:10:09 +0000 Cc: current@freebsd.org Subject: Re: FreeBSD is now self-hosting on the UltraSPARC T1 X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 22 May 2006 18:33:24 -0000 On 5/22/06, Chad Leigh -- Shire.Net LLC wrote: > > On May 21, 2006, at 7:54 PM, m m wrote: > > > While > > on topic, the Opterons aren't SMP either, and neither are the > > ht-Xeons... > > I would like t\o hear the rational for the Opterons (presumably the > dual core ones) not being SMP. They have two independent operating > cores in one physical package. Who cares how it is packaged? I > would tend to agree with you on the ht-Xeon in terms of general > descriptions. I do not know as well how the ht-xeon work as I don't > use any but it seems to me that the "SMP" moniker, at least in > FreeBSD, relate to how things are scheduled. SMP stands for "Symmetric MultiProcessing", which means that multiple processors have equal access latency to memory - typically accomplished by sitting the processors on a shared bus with memory. The MultiProcessor Opterons are _NOT_ SMP, they are _NUMA_ machines, "NonUniform Memory Access"; in the MP Opterons each processor has (or can have) its own "local" memory, which makes up only part of the shared address space. When an Opteron accesses an address that is not in its "local" memory, it has to talk to a remote processor's memory, thereby incurring a different access latency.