X-Original-To: pgsql-patches-postgresql.org@localhost.postgresql.org Received: from localhost (mx1.hub.org [200.46.208.251]) by postgresql.org (Postfix) with ESMTP id A064211F602A for ; Sat, 29 Apr 2006 16:34:39 -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 28008-07 for ; Sat, 29 Apr 2006 16:34:34 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey- Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by postgresql.org (Postfix) with ESMTP id D99C811F6008 for ; Sat, 29 Apr 2006 16:34:32 -0300 (ADT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.13.6/8.13.6) with ESMTP id k3TJYSLn026186; Sat, 29 Apr 2006 15:34:28 -0400 (EDT) To: Theo Schlossnagle cc: Bruce Momjian , josh.berkus@sun.com, robert.lor@sun.com, PostgreSQL-patches Subject: Re: [BUGS] BUG #2401: spinlocks not available on amd64 In-reply-to: <445159FA.7070206@omniti.com> References: <200604272231.k3RMVYM28488@candle.pha.pa.us> <16483.1146178926@sss.pgh.pa.us> <445159FA.7070206@omniti.com> Comments: In-reply-to Theo Schlossnagle message dated "Thu, 27 Apr 2006 19:55:38 -0400" Date: Sat, 29 Apr 2006 15:34:28 -0400 Message-ID: <26185.1146339268@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200604/256 X-Sequence-Number: 19528 Theo Schlossnagle writes: > I'd remind everyone that the spinlock stuff is entirely optional at > build time. Not really. The performance hit for not having hardware spinlocks is so severe that it's not considered a reasonable fallback. > I also think it immensely useful to replace all of the tas subsystem > with cas so that one could reliabily lock these atomics with the process > id of the locker. I cannot, ever once in my years working on Postgres, remember having wanted such a thing. I am strongly against mucking with the spinlock code for mere aesthetics --- it's too fragile and hard to test, especially on platforms you don't have ready access to. In short, it ain't broken and we don't need to fix it. regards, tom lane