From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47600) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V2e0b-0002U7-Ti for qemu-devel@nongnu.org; Fri, 26 Jul 2013 05:08:24 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1V2e0a-0004XK-Qb for qemu-devel@nongnu.org; Fri, 26 Jul 2013 05:08:21 -0400 Received: from mail.avalus.com ([2001:41c8:10:1dd::10]:55802) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V2e0a-0004X9-Kn for qemu-devel@nongnu.org; Fri, 26 Jul 2013 05:08:20 -0400 Date: Fri, 26 Jul 2013 10:08:06 +0100 From: Alex Bligh Message-ID: <5C76DA22418E161C26FCDF26@nimrod.local> In-Reply-To: <20130726084345.GE31438@stefanha-thinkpad.redhat.com> References: <1374396185-10870-1-git-send-email-pingfank@linux.vnet.ibm.com> <20130725120530.GJ21033@stefanha-thinkpad.redhat.com> <51F11AFB.9040008@siemens.com> <1A5D30F9703985AD026648F0@nimrod.local> <20130726084345.GE31438@stefanha-thinkpad.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline Subject: Re: [Qemu-devel] [RFC 0/8] arm AioContext with its own timer stuff Reply-To: Alex Bligh List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Hajnoczi Cc: Kevin Wolf , Stefan Hajnoczi , Alex Bligh , Jan Kiszka , Liu Ping Fan , qemu-devel@nongnu.org, Anthony Liguori , Paolo Bonzini --On 26 July 2013 10:43:45 +0200 Stefan Hajnoczi wrote: > block.c and block/qed.c use vm_clock because block drivers should not do > guest I/O while the vm is stopped. This is especially true during live > migration where it's important to hand off the image file from the > source host to the destination host with good cache consistency. The > source host is not allowed to modify the image file anymore once the > destination host has resumed the guest. > > Block jobs use rt_clock because they aren't considered guest I/O. That's going to be 'interesting' if qemu-img uses a block driver that uses a timer, as I don't think the vm timer is running when qemu-img is running. -- Alex Bligh