From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda3.sgi.com [192.48.176.15]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id q0GHmM6b105866 for ; Mon, 16 Jan 2012 11:48:23 -0600 Received: from bombadil.infradead.org (173-166-109-252-newengland.hfc.comcastbusiness.net [173.166.109.252]) by cuda.sgi.com with ESMTP id sC5mYiSaC8DECn1N for ; Mon, 16 Jan 2012 09:48:20 -0800 (PST) Date: Mon, 16 Jan 2012 12:48:19 -0500 From: Christoph Hellwig Subject: Re: concurrent direct IO write in xfs Message-ID: <20120116174819.GA19417@infradead.org> References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: Zheng Da Cc: xfs@oss.sgi.com On Sun, Jan 15, 2012 at 07:01:42PM -0500, Zheng Da wrote: > Hello, > > I surprisedly found that writing data to a file (no appending) with direct > IO and with multiple threads has the same performance as a single thread. > Actually, it seems there is only one core is working at a time. In my case, > each time I write a page to a file and the offset is always aligned to the > page size, so there is no overlapping between writes. What kernel version are you using? Also, what is the exact I/O pattern? _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs