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>
This commit is contained in:
Pavel Dovgalyuk 2015-09-17 19:24:44 +03:00 committed by Paolo Bonzini
parent efab87cf79
commit 8bd7f71d79
7 changed files with 134 additions and 12 deletions

12
cpus.c
View File

@ -410,6 +410,18 @@ void qemu_clock_warp(QEMUClockType type)
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.

View File

@ -26,6 +26,20 @@ enum ReplayClockKind {
};
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 @@ int64_t replay_read_clock(ReplayClockKind kind);
/*! 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 */

View File

@ -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 @@ bool timerlist_run_timers(QEMUTimerList *timer_list)
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 timerlistgroup_deadline_ns(QEMUTimerListGroup *tlg)
{
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 @@ int64_t qemu_clock_get_ns(QEMUClockType type)
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;

View File

@ -29,6 +29,10 @@ enum ReplayEvents {
/* 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
};

View File

@ -160,3 +160,37 @@ void replay_shutdown_request(void)
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;
}

View File

@ -1,5 +1,6 @@
#include "sysemu/replay.h"
#include <stdlib.h>
#include "sysemu/sysemu.h"
ReplayMode replay_mode;
@ -14,3 +15,8 @@ int64_t replay_read_clock(unsigned int kind)
abort();
return 0;
}
bool replay_checkpoint(ReplayCheckpoint checkpoint)
{
return true;
}

29
vl.c
View File

@ -1642,15 +1642,21 @@ static void qemu_kill_report(void)
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 @@ void qemu_system_killed(int signal, pid_t pid)
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 @@ int main(int argc, char **argv, char **envp)
}
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 @@ int main(int argc, char **argv, char **envp)
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) {