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authorPavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>2018-09-12 11:19:45 +0300
committerPaolo Bonzini <pbonzini@redhat.com>2018-10-02 19:08:51 +0200
commit0c08185f8fe1eb20edec1a2bf32b4d219cc023f0 (patch)
treedab130711a48942f7179666888316612a1e725c0 /replay
parent0a7fa00a13f0852ec6fa83ab987a5ee7978d9867 (diff)
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replay: wake up vCPU when replaying
In record/replay icount mode vCPU thread and iothread synchronize the execution using the checkpoints. vCPU thread processes the virtual timers and iothread processes all others. When iothread wants to wake up sleeping vCPU thread, it sends dummy queued work. Therefore it could be the following sequence of the events in record mode: - IO: sending dummy work - IO: processing timers - CPU: wakeup - CPU: clearing dummy work - CPU: processing virtual timers But due to the races in replay mode the sequence may change: - IO: sending dummy work - CPU: wakeup - CPU: clearing dummy work - CPU: sleeping again because nothing to do - IO: Processing timers - CPU: zzzz In this case vCPU will not wake up, because dummy work is not to be set up again. This patch tries to wake up the vCPU when it sleeps and the icount warp checkpoint isn't met. It means that vCPU has something to do, because there are no other reasons of non-matching warp checkpoint. Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru> -- v5: improve checking that vCPU is still sleeping Message-Id: <20180912081945.3228.19776.stgit@pasha-VirtualBox> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'replay')
-rw-r--r--replay/replay.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/replay/replay.c b/replay/replay.c
index 8228261..379b51a 100644
--- a/replay/replay.c
+++ b/replay/replay.c
@@ -224,6 +224,18 @@ out:
return res;
}
+bool replay_has_checkpoint(void)
+{
+ bool res = false;
+ if (replay_mode == REPLAY_MODE_PLAY) {
+ g_assert(replay_mutex_locked());
+ replay_account_executed_instructions();
+ res = EVENT_CHECKPOINT <= replay_state.data_kind
+ && replay_state.data_kind <= EVENT_CHECKPOINT_LAST;
+ }
+ return res;
+}
+
static void replay_enable(const char *fname, int mode)
{
const char *fmode = NULL;