replay: checkpoints
This patch introduces checkpoints that synchronize cpu thread and iothread.
When checkpoint is met in the code all asynchronous events from the queue
are executed.
Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>
Message-Id: <20150917162444.8676.52916.stgit@PASHA-ISP.def.inno>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>
diff --git a/cpus.c b/cpus.c
index 1a7318f..2619fd0 100644
--- a/cpus.c
+++ b/cpus.c
@@ -410,6 +410,18 @@
return;
}
+ /* Nothing to do if the VM is stopped: QEMU_CLOCK_VIRTUAL timers
+ * do not fire, so computing the deadline does not make sense.
+ */
+ if (!runstate_is_running()) {
+ return;
+ }
+
+ /* warp clock deterministically in record/replay mode */
+ if (!replay_checkpoint(CHECKPOINT_CLOCK_WARP)) {
+ return;
+ }
+
if (icount_sleep) {
/*
* If the CPUs have been sleeping, advance QEMU_CLOCK_VIRTUAL timer now.
diff --git a/include/sysemu/replay.h b/include/sysemu/replay.h
index fcc93d1..e2696fe 100644
--- a/include/sysemu/replay.h
+++ b/include/sysemu/replay.h
@@ -26,6 +26,20 @@
};
typedef enum ReplayClockKind ReplayClockKind;
+/* IDs of the checkpoints */
+enum ReplayCheckpoint {
+ CHECKPOINT_CLOCK_WARP,
+ CHECKPOINT_RESET_REQUESTED,
+ CHECKPOINT_SUSPEND_REQUESTED,
+ CHECKPOINT_CLOCK_VIRTUAL,
+ CHECKPOINT_CLOCK_HOST,
+ CHECKPOINT_CLOCK_VIRTUAL_RT,
+ CHECKPOINT_INIT,
+ CHECKPOINT_RESET,
+ CHECKPOINT_COUNT
+};
+typedef enum ReplayCheckpoint ReplayCheckpoint;
+
extern ReplayMode replay_mode;
/* Processing the instructions */
@@ -70,6 +84,12 @@
/*! Called when qemu shutdown is requested. */
void replay_shutdown_request(void);
+/*! Should be called at check points in the execution.
+ These check points are skipped, if they were not met.
+ Saves checkpoint in the SAVE mode and validates in the PLAY mode.
+ Returns 0 in PLAY mode if checkpoint was not found.
+ Returns 1 in all other cases. */
+bool replay_checkpoint(ReplayCheckpoint checkpoint);
/* Asynchronous events queue */
diff --git a/qemu-timer.c b/qemu-timer.c
index 3dc847b..f16e422 100644
--- a/qemu-timer.c
+++ b/qemu-timer.c
@@ -25,6 +25,7 @@
#include "qemu/main-loop.h"
#include "qemu/timer.h"
#include "sysemu/replay.h"
+#include "sysemu/sysemu.h"
#ifdef CONFIG_POSIX
#include <pthread.h>
@@ -478,10 +479,31 @@
void *opaque;
qemu_event_reset(&timer_list->timers_done_ev);
- if (!timer_list->clock->enabled) {
+ if (!timer_list->clock->enabled || !timer_list->active_timers) {
goto out;
}
+ switch (timer_list->clock->type) {
+ case QEMU_CLOCK_REALTIME:
+ break;
+ default:
+ case QEMU_CLOCK_VIRTUAL:
+ if (!replay_checkpoint(CHECKPOINT_CLOCK_VIRTUAL)) {
+ goto out;
+ }
+ break;
+ case QEMU_CLOCK_HOST:
+ if (!replay_checkpoint(CHECKPOINT_CLOCK_HOST)) {
+ goto out;
+ }
+ break;
+ case QEMU_CLOCK_VIRTUAL_RT:
+ if (!replay_checkpoint(CHECKPOINT_CLOCK_VIRTUAL_RT)) {
+ goto out;
+ }
+ break;
+ }
+
current_time = qemu_clock_get_ns(timer_list->clock->type);
for(;;) {
qemu_mutex_lock(&timer_list->active_timers_lock);
@@ -545,11 +567,17 @@
{
int64_t deadline = -1;
QEMUClockType type;
+ bool play = replay_mode == REPLAY_MODE_PLAY;
for (type = 0; type < QEMU_CLOCK_MAX; type++) {
- if (qemu_clock_use_for_deadline(tlg->tl[type]->clock->type)) {
- deadline = qemu_soonest_timeout(deadline,
- timerlist_deadline_ns(
- tlg->tl[type]));
+ if (qemu_clock_use_for_deadline(type)) {
+ if (!play || type == QEMU_CLOCK_REALTIME) {
+ deadline = qemu_soonest_timeout(deadline,
+ timerlist_deadline_ns(tlg->tl[type]));
+ } else {
+ /* Read clock from the replay file and
+ do not calculate the deadline, based on virtual clock. */
+ qemu_clock_get_ns(type);
+ }
}
}
return deadline;
@@ -574,8 +602,7 @@
now = REPLAY_CLOCK(REPLAY_CLOCK_HOST, get_clock_realtime());
last = clock->last;
clock->last = now;
- if ((now < last || now > (last + get_max_clock_jump()))
- && replay_mode == REPLAY_MODE_NONE) {
+ if (now < last || now > (last + get_max_clock_jump())) {
notifier_list_notify(&clock->reset_notifiers, &now);
}
return now;
diff --git a/replay/replay-internal.h b/replay/replay-internal.h
index 4414695..bf64be5 100644
--- a/replay/replay-internal.h
+++ b/replay/replay-internal.h
@@ -29,6 +29,10 @@
/* some of greater codes are reserved for clocks */
EVENT_CLOCK,
EVENT_CLOCK_LAST = EVENT_CLOCK + REPLAY_CLOCK_COUNT - 1,
+ /* for checkpoint event */
+ /* some of greater codes are reserved for checkpoints */
+ EVENT_CHECKPOINT,
+ EVENT_CHECKPOINT_LAST = EVENT_CHECKPOINT + CHECKPOINT_COUNT - 1,
EVENT_COUNT
};
diff --git a/replay/replay.c b/replay/replay.c
index 65dca7f..44fbed9 100644
--- a/replay/replay.c
+++ b/replay/replay.c
@@ -160,3 +160,37 @@
replay_mutex_unlock();
}
}
+
+bool replay_checkpoint(ReplayCheckpoint checkpoint)
+{
+ bool res = false;
+ assert(EVENT_CHECKPOINT + checkpoint <= EVENT_CHECKPOINT_LAST);
+ replay_save_instructions();
+
+ if (!replay_file) {
+ return true;
+ }
+
+ replay_mutex_lock();
+
+ if (replay_mode == REPLAY_MODE_PLAY) {
+ if (replay_next_event_is(EVENT_CHECKPOINT + checkpoint)) {
+ replay_finish_event();
+ } else if (replay_data_kind != EVENT_ASYNC) {
+ res = false;
+ goto out;
+ }
+ replay_read_events(checkpoint);
+ /* replay_read_events may leave some unread events.
+ Return false if not all of the events associated with
+ checkpoint were processed */
+ res = replay_data_kind != EVENT_ASYNC;
+ } else if (replay_mode == REPLAY_MODE_RECORD) {
+ replay_put_event(EVENT_CHECKPOINT + checkpoint);
+ replay_save_events(checkpoint);
+ res = true;
+ }
+out:
+ replay_mutex_unlock();
+ return res;
+}
diff --git a/stubs/replay.c b/stubs/replay.c
index f0d95b0..3354fcf 100644
--- a/stubs/replay.c
+++ b/stubs/replay.c
@@ -1,5 +1,6 @@
#include "sysemu/replay.h"
#include <stdlib.h>
+#include "sysemu/sysemu.h"
ReplayMode replay_mode;
@@ -14,3 +15,8 @@
abort();
return 0;
}
+
+bool replay_checkpoint(ReplayCheckpoint checkpoint)
+{
+ return true;
+}
diff --git a/vl.c b/vl.c
index f481a1e..8806092 100644
--- a/vl.c
+++ b/vl.c
@@ -1642,15 +1642,21 @@
static int qemu_reset_requested(void)
{
int r = reset_requested;
- reset_requested = 0;
- return r;
+ if (r && replay_checkpoint(CHECKPOINT_RESET_REQUESTED)) {
+ reset_requested = 0;
+ return r;
+ }
+ return false;
}
static int qemu_suspend_requested(void)
{
int r = suspend_requested;
- suspend_requested = 0;
- return r;
+ if (r && replay_checkpoint(CHECKPOINT_SUSPEND_REQUESTED)) {
+ suspend_requested = 0;
+ return r;
+ }
+ return false;
}
static WakeupReason qemu_wakeup_requested(void)
@@ -1798,7 +1804,12 @@
shutdown_signal = signal;
shutdown_pid = pid;
no_shutdown = 0;
- qemu_system_shutdown_request();
+
+ /* Cannot call qemu_system_shutdown_request directly because
+ * we are in a signal handler.
+ */
+ shutdown_requested = 1;
+ qemu_notify_event();
}
void qemu_system_shutdown_request(void)
@@ -4483,6 +4494,10 @@
}
qemu_add_globals();
+ /* This checkpoint is required by replay to separate prior clock
+ reading from the other reads, because timer polling functions query
+ clock values from the log. */
+ replay_checkpoint(CHECKPOINT_INIT);
qdev_machine_init();
current_machine->ram_size = ram_size;
@@ -4601,6 +4616,10 @@
exit(1);
}
+ /* This checkpoint is required by replay to separate prior clock
+ reading from the other reads, because timer polling functions query
+ clock values from the log. */
+ replay_checkpoint(CHECKPOINT_RESET);
qemu_system_reset(VMRESET_SILENT);
register_global_state();
if (loadvm) {
