From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37918) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XCTnK-0007aW-Bd for qemu-devel@nongnu.org; Wed, 30 Jul 2014 09:19:55 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XCTnE-0000e5-Sn for qemu-devel@nongnu.org; Wed, 30 Jul 2014 09:19:50 -0400 Received: from [2001:41d0:8:2b42::1] (port=58683 helo=greensocs.com) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XCTnE-0000dx-Ho for qemu-devel@nongnu.org; Wed, 30 Jul 2014 09:19:44 -0400 Message-ID: <53D8F0EE.1090706@greensocs.com> Date: Wed, 30 Jul 2014 15:19:42 +0200 From: Frederic Konrad MIME-Version: 1.0 References: <20140717110153.8352.80175.stgit@PASHA-ISP> <53D14707.7080509@redhat.com> <2596.37912172384$1406533875@news.gmane.org> <53D62210.9060903@redhat.com> <000101cfabca$07016870$15043950$@Dovgaluk@ispras.ru> <53D8B9F8.7090804@redhat.com> In-Reply-To: <53D8B9F8.7090804@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC PATCH v2 00/49] Series short description List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini , Pavel Dovgaluk , qemu-devel@nongnu.org Cc: peter.maydell@linaro.org, peter.crosthwaite@xilinx.com, mark.burton@greensocs.com, real@ispras.ru, batuzovk@ispras.ru On 30/07/2014 11:25, Paolo Bonzini wrote: > Il 30/07/2014 09:44, Pavel Dovgaluk ha scritto: >>> From: Paolo Bonzini [mailto:paolo.bonzini@gmail.com] On Behalf Of Paolo Bonzini >>>>> - patch 16 should also use subsections, and perhaps apply to all other >>>>> CPUs too? >>>> We implemented replay only for i386 and ARM. If we'll change other targets, it will not >>>> add record/replay capabilities to them, but can confuse the reviewers. >>> Why are these fields only required by record/replay? >> No, these fields can cause non-determinism for normal execution mode too. >> But these changes are not related to reverse execution. I can make patches for them >> and submit them separately, if needed. > Yes, thanks. If it causes nondeterminism for normal execution mode too, > it's better to apply them to all targets. If possible use a subsection, > though. > >>>>> - patch 27 makes sense but VIRTUAL is used to skip blinking when the VM >>>>> is stopped >>>> Right, this is kind of hack. I haven't found better solution yet. >>> I think it's okay to use REALTIME, just add runstate_is_running() to the >>> "if (now >= s->cursor_blink_time)". >>> >>> That said, "every read to virtual clock is written to the >>> replay log" worries me a bit from the point of view of thread-safety. >>> Do you need to log all reads because you don't use icount? Reads can >>> only happen at given points if you use icount, and you could simply log >>> the icount value at each synchronization point. >> We made two implementations of virtual clock. One uses host realtime clock >> and thus should be written into the log. Another one uses icount and calculated >> in one of the replay modules (similar to regular icount implementation). >> This patch series contains only first implementation, because it looks more convenient: >> user does not have to specify icount shift value, when starting the recording or replaying. > I think from the upstreaming point of view it's better to stick with > what makes the code simpler. Start by submitting only the icount-based > implementation, the other can come later. > > Paolo Hi all, I think that's actually our implementation cover no? (http://lists.gnu.org/archive/html/qemu-devel/2014-07/msg00677.html) Fred