From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932428AbWAKSM5 (ORCPT ); Wed, 11 Jan 2006 13:12:57 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932426AbWAKSM5 (ORCPT ); Wed, 11 Jan 2006 13:12:57 -0500 Received: from web34103.mail.mud.yahoo.com ([66.163.178.101]:13242 "HELO web34103.mail.mud.yahoo.com") by vger.kernel.org with SMTP id S932422AbWAKSM4 (ORCPT ); Wed, 11 Jan 2006 13:12:56 -0500 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=Message-ID:Received:Date:From:Subject:To:MIME-Version:Content-Type:Content-Transfer-Encoding; b=vQEwRQHN7jtXLPOkLmY+Sa6B4CeokRAw8pHxAbAQzwGrjHG9RivRoxKR8S4In/iYXI0dTaUK0tvztoCKSBcqwhS01jC5EN4HM+dQ1tfZL7SwhmTRj6Ufzugy9wp1yB1Su8SnIxHNJ1eq67Am974Xp/uM0/CdPeNYLOzHbna5CPY= ; Message-ID: <20060111181252.61498.qmail@web34103.mail.mud.yahoo.com> Date: Wed, 11 Jan 2006 10:12:52 -0800 (PST) From: Kenny Simpson Subject: Is user-space AIO dead? To: linux kernel MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi, Having read the excellent paper by IBM presented at the 2003 OLS about Asynchronous I/O Support in Linux 2.5, I found the conclusion rather disappointing: "In conclusion, there appears to be no conditions for raw or O_DIRECT access under which AIO can show a noticable benefit." - p385. http://archive.linuxsymposium.org/ols2003/Proceedings/All-Reprints/Reprint-Pulavarty-OLS2003.pdf Is this still the case? If I want a transactional engine (like a database) that needs to persist to stable storage, is it still best to use a helper thread to do write/fsync or O_SYNC|O_DIRECT? -Kenny __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com