From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1G5fYe-0007mX-Sf for qemu-devel@nongnu.org; Wed, 26 Jul 2006 05:20:01 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1G5fYd-0007ld-7N for qemu-devel@nongnu.org; Wed, 26 Jul 2006 05:20:00 -0400 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1G5fYd-0007lY-1Z for qemu-devel@nongnu.org; Wed, 26 Jul 2006 05:19:59 -0400 Received: from [64.78.21.128] (helo=mis011-1.exch011.intermedia.net) by monty-python.gnu.org with esmtp (Exim 4.52) id 1G5fa8-0004ZH-EN for qemu-devel@nongnu.org; Wed, 26 Jul 2006 05:21:32 -0400 Message-ID: <44C733B9.9080705@qumranet.com> Date: Wed, 26 Jul 2006 12:19:53 +0300 From: Avi Kivity MIME-Version: 1.0 Subject: Re: [Qemu-devel] Wipe patch References: <44C72AD0.1090004@wasp.net.au> In-Reply-To: <44C72AD0.1090004@wasp.net.au> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Brad Campbell wrote: > ZIGLIO, Frediano, VF-IT wrote: >> Hi, >> well, this is not a definitive patch but it works. The aim is to be >> able to wipe the disk without allocating entire space. When you wipe a >> disk the program fill disk with zero bytes so disk image increase to >> allocate all space. This just patch detect null byte writes and do not >> write all zero byte clusters. > > This _looks_ like it would severely impact cpu load during a write. > Have you done any testing to determine if this is likely to impact a > normal usage scenario? Why would it? In most cases, the zero test would terminate quickly, without accessing the entire cluster. -- error compiling committee.c: too many arguments to function