From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1MGViA-0003p4-Ix for qemu-devel@nongnu.org; Tue, 16 Jun 2009 06:16:14 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1MGVi5-0003jj-TS for qemu-devel@nongnu.org; Tue, 16 Jun 2009 06:16:13 -0400 Received: from [199.232.76.173] (port=38388 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MGVi5-0003jb-KE for qemu-devel@nongnu.org; Tue, 16 Jun 2009 06:16:09 -0400 Received: from mx2.redhat.com ([66.187.237.31]:57729) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1MGVi5-0001fC-9B for qemu-devel@nongnu.org; Tue, 16 Jun 2009 06:16:09 -0400 Received: from int-mx2.corp.redhat.com (int-mx2.corp.redhat.com [172.16.27.26]) by mx2.redhat.com (8.13.8/8.13.8) with ESMTP id n5GAG85b017374 for ; Tue, 16 Jun 2009 06:16:08 -0400 Message-ID: <4A3770A6.9000904@redhat.com> Date: Tue, 16 Jun 2009 12:15:02 +0200 From: Kevin Wolf MIME-Version: 1.0 Subject: Re: [Qemu-devel] [PATCH 0/3] qcow2: Write complete sectors References: <1245144690-27805-1-git-send-email-kwolf@redhat.com> <4A376DEB.4070008@redhat.com> In-Reply-To: <4A376DEB.4070008@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: dlaor@redhat.com Cc: qemu-devel@nongnu.org Dor Laor schrieb: > On 06/16/2009 12:31 PM, Kevin Wolf wrote: >> Once upon a time, there was a bdrv_pwrite that actually wrote single bytes to >> the file... However, today it is emulated by a read-modify-write cycle which >> aligns the request to sector size. This is slow. And we don't need it: qcow2 >> often has the complete sector in memory, we don't need to read it from the disk >> again. >> >> These patches change the writes to L1 tables, L2 tables and refcount blocks to >> write complete sectors instead of single entries. >> >> This series depends on the qcow2 split to apply cleanly. >> >> > > If it's not an RFC, you better prepare a git tree for Anthony to pull from I can do that, but the patches need to be on the list anyway. > and described how did you test it. Maybe committing the qemu-io scripts > would also be a move in the right direction. Anthony is promising for a while now that he will push his tests to the tree. Once he has done so, I'll consider integrating my script. Kevin