X-Original-To: pgsql-performance-postgresql.org@postgresql.org Received: from localhost (mx1.hub.org [200.46.208.251]) by postgresql.org (Postfix) with ESMTP id F1DC59FA4A8 for ; Mon, 12 Jun 2006 23:16:30 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.208.251]) (amavisd-new, port 10024) with ESMTP id 03698-03 for ; Mon, 12 Jun 2006 23:16:20 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey- Received: from mail.envysolutions.com (mark.mielke.cc [206.248.142.186]) by postgresql.org (Postfix) with ESMTP id 4A0FB9FA10A for ; Mon, 12 Jun 2006 23:16:22 -0300 (ADT) Received: from localhost (localhost.localdomain [127.0.0.1]) by mail.envysolutions.com (Postfix) with ESMTP id 5C1F31B69A; Mon, 12 Jun 2006 22:16:27 -0400 (EDT) Received: from mail.envysolutions.com ([127.0.0.1]) by localhost (mark.mielke.cc [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 04379-08; Mon, 12 Jun 2006 22:16:27 -0400 (EDT) Received: by mail.envysolutions.com (Postfix, from userid 500) id 421F21B69B; Mon, 12 Jun 2006 22:16:27 -0400 (EDT) Date: Mon, 12 Jun 2006 22:16:27 -0400 From: mark@mark.mielke.cc To: Anthony Presley , pgsql-performance@postgresql.org Subject: Re: 64-bit vs 32-bit performance ... backwards? Message-ID: <20060613021627.GA4682@mark.mielke.cc> References: <1150151282.14661.42.camel@tigger> <20060613000441.GI8588@kenobi.snowman.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060613000441.GI8588@kenobi.snowman.net> User-Agent: Mutt/1.4.2.1i X-Virus-Scanned: amavisd-new at mail.envysolutions.com X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200606/153 X-Sequence-Number: 19510 I've been trying to track this stuff - in fact, I'll likely be switching from AMD32 to AMD64 in the next few weeks. I believe I have a handle on the + vs - of 64-bit. It makes sense that full 64-bit would be slower. At an extreme it halfs the amount of available memory or doubles the required memory bandwidth, depending on the work load. Has anybody taken a look at PostgreSQL to ensure that it uses 32-bit integers instead of 64-bit integers where only 32-bit is necessary? 32-bit offsets instead of 64-bit pointers? This sort of thing? I haven't. I'm meaning to take a look. Within registers, 64-bit should be equal speed to 32-bit. Outside the registers, it would make sense to only deal with the lower 32-bits where 32-bits is all that is required. Cheers, mark -- mark@mielke.cc / markm@ncf.ca / markm@nortel.com __________________________ . . _ ._ . . .__ . . ._. .__ . . . .__ | Neighbourhood Coder |\/| |_| |_| |/ |_ |\/| | |_ | |/ |_ | | | | | | \ | \ |__ . | | .|. |__ |__ | \ |__ | Ottawa, Ontario, Canada One ring to rule them all, one ring to find them, one ring to bring them all and in the darkness bind them... http://mark.mielke.cc/