Il 30/07/2014 09:44, Pavel Dovgaluk ha scritto: >> From: Paolo Bonzini [mailto:paolo.bonz...@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
