From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57427) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XPWPv-0005Pt-2b for qemu-devel@nongnu.org; Thu, 04 Sep 2014 08:45:39 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XPWPn-000144-1S for qemu-devel@nongnu.org; Thu, 04 Sep 2014 08:45:34 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33490) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XPWPm-00013d-QL for qemu-devel@nongnu.org; Thu, 04 Sep 2014 08:45:26 -0400 Date: Thu, 4 Sep 2014 13:45:19 +0100 From: "Richard W.M. Jones" Message-ID: <20140904124519.GB1302@redhat.com> References: <67d97abc587e7c6985166dbe800686938ac8adb5.1409299732.git.hutao@cn.fujitsu.com> <20140904123522.GH3897@noname.str.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140904123522.GH3897@noname.str.redhat.com> Subject: Re: [Qemu-devel] [PATCH v13 5/6] raw-posix: Add full preallocation option List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kevin Wolf Cc: Fam Zheng , Hu Tao , qemu-devel@nongnu.org, Max Reitz , Stefan Hajnoczi , Yasunori Goto On Thu, Sep 04, 2014 at 02:35:22PM +0200, Kevin Wolf wrote: > Please change the code to always write zeros for FULL, How is this useful for anyone? You don't know if the underlying SAN is going to detect these zeroes or combine these blocks together. It's just slow for no reason. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com Fedora Windows cross-compiler. Compile Windows programs, test, and build Windows installers. Over 100 libraries supported. http://fedoraproject.org/wiki/MinGW