X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (av.hub.org [200.46.204.144]) by postgresql.org (Postfix) with ESMTP id 705559DC84A for ; Wed, 21 Dec 2005 19:57:59 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024) with ESMTP id 46689-06 for ; Wed, 21 Dec 2005 19:58:01 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey- Received: from floppy.pyrenet.fr (floppy.pyrenet.fr [194.116.145.2]) by postgresql.org (Postfix) with ESMTP id 92B259DC85D for ; Wed, 21 Dec 2005 19:57:56 -0400 (AST) Received: by floppy.pyrenet.fr (Postfix, from userid 106) id B70163093C; Thu, 22 Dec 2005 00:57:59 +0100 (MET) From: William Yu X-Newsgroups: pgsql.performance Subject: Re: What's the best hardver for PostgreSQL 8.1? Date: Wed, 21 Dec 2005 15:57:56 -0800 Organization: Hub.Org Networking Services Lines: 9 Message-ID: References: <43A84D03.7090002@ritek.hu> <200512201950.47671.caseroj@comcast.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Complaints-To: usenet@news.hub.org User-Agent: Mozilla Thunderbird 1.0.7 (X11/20050923) X-Accept-Language: en-us, en In-Reply-To: <200512201950.47671.caseroj@comcast.net> To: pgsql-performance@postgresql.org X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, score=0 required=5 tests=[none] X-Spam-Score: 0 X-Spam-Level: X-Archive-Number: 200512/547 X-Sequence-Number: 16368 Juan Casero wrote: > Can you elaborate on the reasons the opteron is better than the Xeon when it > comes to disk io? I have a PostgreSQL 7.4.8 box running a DSS. One of our Opterons have 64-bit IOMMU -- Xeons don't. That means in 64-bit mode, transfers to > 4GB, the OS must allocated the memory < 4GB, DMA to that block and then the CPU must do extra work in copying the memory to > 4GB. Versus on the Opteron, it's done by the IO adaptor using DMA in the background.