From oracle-l-bounce@freelists.org Wed May 5 00:16:38 2004 Return-Path: Received: from air189.startdedicated.com (root@localhost) by orafaq.com (8.11.6/8.11.6) with ESMTP id i455GMe27936 for ; Wed, 5 May 2004 00:16:32 -0500 X-ClientAddr: 206.53.239.180 Received: from turing.freelists.org (freelists-180.iquest.net [206.53.239.180]) by air189.startdedicated.com (8.11.6/8.11.6) with ESMTP id i455G2627910 for ; Wed, 5 May 2004 00:16:22 -0500 Received: from localhost (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id DDAC572CA57; Wed, 5 May 2004 00:07:00 -0500 (EST) Received: from turing.freelists.org ([127.0.0.1]) by localhost (turing [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 06225-21; Wed, 5 May 2004 00:07:00 -0500 (EST) Received: from turing (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id 2C13672CB29; Wed, 5 May 2004 00:07:00 -0500 (EST) Received: with ECARTIS (v1.0.0; list oracle-l); Wed, 05 May 2004 00:05:47 -0500 (EST) X-Original-To: oracle-l@freelists.org Delivered-To: oracle-l@freelists.org Received: from localhost (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id EAA9E72C8C9 for ; Wed, 5 May 2004 00:05:46 -0500 (EST) Received: from turing.freelists.org ([127.0.0.1]) by localhost (turing [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 03704-66 for ; Wed, 5 May 2004 00:05:46 -0500 (EST) Received: from smtp.vip.163.com (smtp.vip.163.com [202.106.168.106]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id 69F7072C8A5 for ; Wed, 5 May 2004 00:05:46 -0500 (EST) Received: from localhost (localhost [127.0.0.1]) by smtp.vip.163.com (Postfix) with SMTP id 05FBF47A3 for ; Wed, 5 May 2004 13:19:29 +0800 (CST) Received: from LSHACHZHU (unknown [220.248.6.124]) by 202.106.168.106 (Coremail:vip.163.com) with SMTP id BwEAAF55mEAsMQZ8.1 for ; Wed, 05 May 2004 13:19:29 +0800 (CST) X-TEBIE-Originating-IP: [220.248.6.124] Message-ID: <002b01c43260$89c14350$2552fc0a@corp.ebay.com> From: "zhu chao" To: References: <000001c43250$efe10310$6501a8c0@winston> Subject: Re: aio on sun ufs problem Date: Wed, 5 May 2004 13:19:26 +0800 MIME-Version: 1.0 Content-type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1158 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 X-Virus-Scanned: by amavisd-new at freelists.org X-archive-position: 4407 X-ecartis-version: Ecartis v1.0.0 Sender: oracle-l-bounce@freelists.org Errors-To: oracle-l-bounce@freelists.org X-original-sender: chao_ping@vip.163.com Precedence: normal Reply-To: oracle-l@freelists.org X-list: oracle-l X-Virus-Scanned: by amavisd-new at freelists.org That is the point. The cost and benefit of using lwp based aio on filesystem, is it worthy or not. I saw note saying the cost of thread management and context switch is big, using LWP based AIO. Does any has measured the cost? (http://www.ixora.com.au/q+a/0011/14171201.htm) Another question, does aio only means asynch write(non-blocking write), is there concept like asynch read? I did a test doing a full table scan on a table which is a raw device. The os is doing pread os call, not kaio(aioread...). If only write benefit from asynch IO, then only dbwr/lgwr will benefit from KAIO. So when dbwr and lwgr can catch up clean the dirty buffer, whether to using aio does not matters.As server process only does read on datafile, and server process used most of system resource on a big system.(server process does write only during direct read/write and creating tablespace,as far as I know). Just some thought and questions about this topic. Regards Zhu Chao. ----- Original Message ----- > > --- > Aio on solaris is enabled by default if you use disk_asynch_io =3D true. = > You > will see a failed system call to kaio and then pread pwrite processes = > spawn > to simulate aio via light weight threaded processing. > You can verify this in the same way using truss against dbwr. I'm not = > sure > what -t does, but if you just truss on dbwr process you will see the > behavior. I personally feel that dbwr_io_slaves when weighed against = > these > facts are better suted at simulating aio than the light weight threaded > processes. > - David > > ---------------------------------------------------------------- Please see the official ORACLE-L FAQ: http://www.orafaq.com ---------------------------------------------------------------- To unsubscribe send email to: oracle-l-request@freelists.org put 'unsubscribe' in the subject line. -- Archives are at http://www.freelists.org/archives/oracle-l/ FAQ is at http://www.freelists.org/help/fom-serve/cache/1.html -----------------------------------------------------------------