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 4A3949DC8DE for ; Tue, 21 Mar 2006 08:34:19 -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 62102-01 for ; Tue, 21 Mar 2006 08:34:21 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey- Received: from noel.decibel.org (noel.decibel.org [67.100.216.10]) by postgresql.org (Postfix) with ESMTP id 72ED99DC84A for ; Tue, 21 Mar 2006 08:34:15 -0400 (AST) Received: by noel.decibel.org (Postfix, from userid 1001) id 85A9F56427; Tue, 21 Mar 2006 06:34:19 -0600 (CST) Received: (hashcash-sendmail, from uid 1001); Tue, 21 Mar 2006 06:34:17 -0600 Date: Tue, 21 Mar 2006 06:34:17 -0600 From: "Jim C. Nasby" To: Alex Hayward Cc: Mark Kirkwood , Vivek Khera , Postgresql Performance Subject: Re: Best OS & Configuration for Dual Xeon w/4GB & Adaptec Message-ID: <20060321123417.GW15742@pervasive.com> References: <20060317221116.GA14661@juniper.net> <8F6490E1-64E2-406B-A559-7DA8BA1EB197@khera.org> <20060321103219.GD15742@pervasive.com> <441FDD7E.7050106@paradise.net.nz> <20060321114658.GK15742@pervasive.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Operating-System: FreeBSD 6.0-RELEASE-p4 amd64 X-Distributed: Join the Effort! http://www.distributed.net User-Agent: Mutt/1.5.11 X-Hashcash: 1:20:060321:xelah-pgsql@xelah.com::/roxNwnkkYhHDJty:0000000000000000 0000000000000000000000008Kqa X-Hashcash: 1:20:060321:markir@paradise.net.nz::EjN7y0mKFZo3Xnpq:000000000000000 0000000000000000000000000BNC X-Hashcash: 1:20:060321:vivek@khera.org::jxTzLuh24dYby41E:005tDZ X-Hashcash: 1:20:060321:pgsql-performance@postgresql.org::CfNGnXawlTbqtSAN:00000 000000000000000000000000DH3d X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, score=0.108 required=5 tests=[AWL=0.108] X-Spam-Score: 0.108 X-Spam-Level: X-Archive-Number: 200603/396 X-Sequence-Number: 17833 On Tue, Mar 21, 2006 at 12:22:31PM +0000, Alex Hayward wrote: > On Tue, 21 Mar 2006, Jim C. Nasby wrote: > > > On Tue, Mar 21, 2006 at 11:03:26PM +1200, Mark Kirkwood wrote: > > > > > > So its really all about accounting, in a sense - whether pages end up in > > > the 'Buf' or 'Inactive' queue, they are still cached! > > > > So what's the difference between Buf and Active then? Just that active > > means it's a code page, or that it's been directly mapped into a > > processes memory (perhaps via mmap)? > > I don't think that Buf and Active are mutually exclusive. Try adding up > Active, Inactive, Cache, Wired, Buf and Free - it'll come to more than > your physical memory. > > Active gives an amount of physical memory. Buf gives an amount of > kernel-space virtual memory which provide the kernel with a window on to > pages in the other categories. In fact, I don't think that 'Buf' really > belongs in the list as it doesn't represent a 'type' of page at all. Ahhh, I get it... a KVM (what's that stand for anyway?) is required any time the kernel wants to access a page that doesn't belong to it, right? And actually, I just checked 4 machines and adding all the queues plus buf together didn't add up to total memory except on one of them (there adding just the queues came close; 1507.6MB on a 1.5GB machine). -- Jim C. Nasby, Sr. Engineering Consultant jnasby@pervasive.com Pervasive Software http://pervasive.com work: 512-231-6117 vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461