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https://github.com/qemu/qemu.git
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Add support for dynamic ticks, by Luca Tettamanti and Dan Kenigsberg.
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@3130 c046a42c-6fe2-441c-8c8c-71466251a162
This commit is contained in:
ths
parent
f3dcfadac7
commit
efe75411ec
185
vl.c
185
vl.c
@ -784,12 +784,32 @@ struct QEMUTimer {
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struct qemu_alarm_timer {
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char const *name;
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unsigned int flags;
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int (*start)(struct qemu_alarm_timer *t);
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void (*stop)(struct qemu_alarm_timer *t);
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void (*rearm)(struct qemu_alarm_timer *t);
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void *priv;
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};
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#define ALARM_FLAG_DYNTICKS 0x1
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static inline int alarm_has_dynticks(struct qemu_alarm_timer *t)
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{
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return t->flags & ALARM_FLAG_DYNTICKS;
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}
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static void qemu_rearm_alarm_timer(struct qemu_alarm_timer *t)
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{
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if (!alarm_has_dynticks(t))
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return;
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t->rearm(t);
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}
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/* TODO: MIN_TIMER_REARM_US should be optimized */
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#define MIN_TIMER_REARM_US 250
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static struct qemu_alarm_timer *alarm_timer;
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#ifdef _WIN32
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@ -802,12 +822,17 @@ struct qemu_alarm_win32 {
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static int win32_start_timer(struct qemu_alarm_timer *t);
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static void win32_stop_timer(struct qemu_alarm_timer *t);
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static void win32_rearm_timer(struct qemu_alarm_timer *t);
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#else
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static int unix_start_timer(struct qemu_alarm_timer *t);
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static void unix_stop_timer(struct qemu_alarm_timer *t);
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static int dynticks_start_timer(struct qemu_alarm_timer *t);
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static void dynticks_stop_timer(struct qemu_alarm_timer *t);
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static void dynticks_rearm_timer(struct qemu_alarm_timer *t);
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#ifdef __linux__
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static int hpet_start_timer(struct qemu_alarm_timer *t);
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@ -816,21 +841,26 @@ static void hpet_stop_timer(struct qemu_alarm_timer *t);
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static int rtc_start_timer(struct qemu_alarm_timer *t);
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static void rtc_stop_timer(struct qemu_alarm_timer *t);
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#endif
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#endif /* __linux__ */
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#endif /* _WIN32 */
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static struct qemu_alarm_timer alarm_timers[] = {
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#ifndef _WIN32
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{"dynticks", ALARM_FLAG_DYNTICKS, dynticks_start_timer,
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dynticks_stop_timer, dynticks_rearm_timer, NULL},
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#ifdef __linux__
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/* HPET - if available - is preferred */
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{"hpet", hpet_start_timer, hpet_stop_timer, NULL},
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{"hpet", 0, hpet_start_timer, hpet_stop_timer, NULL, NULL},
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/* ...otherwise try RTC */
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{"rtc", rtc_start_timer, rtc_stop_timer, NULL},
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{"rtc", 0, rtc_start_timer, rtc_stop_timer, NULL, NULL},
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#endif
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#ifndef _WIN32
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{"unix", unix_start_timer, unix_stop_timer, NULL},
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{"unix", 0, unix_start_timer, unix_stop_timer, NULL, NULL},
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#else
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{"win32", win32_start_timer, win32_stop_timer, &alarm_win32_data},
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{"dynticks", ALARM_FLAG_DYNTICKS, win32_start_timer,
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win32_stop_timer, win32_rearm_timer, &alarm_win32_data},
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{"win32", 0, win32_start_timer,
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win32_stop_timer, NULL, &alarm_win32_data},
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#endif
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{NULL, }
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};
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@ -949,6 +979,8 @@ void qemu_del_timer(QEMUTimer *ts)
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}
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pt = &t->next;
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}
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qemu_rearm_alarm_timer(alarm_timer);
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}
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/* modify the current timer so that it will be fired when current_time
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@ -1008,6 +1040,7 @@ static void qemu_run_timers(QEMUTimer **ptimer_head, int64_t current_time)
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/* run the callback (the timer list can be modified) */
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ts->cb(ts->opaque);
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}
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qemu_rearm_alarm_timer(alarm_timer);
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}
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int64_t qemu_get_clock(QEMUClock *clock)
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@ -1115,7 +1148,8 @@ static void host_alarm_handler(int host_signum)
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last_clock = ti;
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}
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#endif
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if (qemu_timer_expired(active_timers[QEMU_TIMER_VIRTUAL],
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if (alarm_has_dynticks(alarm_timer) ||
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qemu_timer_expired(active_timers[QEMU_TIMER_VIRTUAL],
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qemu_get_clock(vm_clock)) ||
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qemu_timer_expired(active_timers[QEMU_TIMER_REALTIME],
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qemu_get_clock(rt_clock))) {
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@ -1136,6 +1170,30 @@ static void host_alarm_handler(int host_signum)
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}
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}
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static uint64_t qemu_next_deadline(void)
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{
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int64_t nearest_delta_us = ULLONG_MAX;
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int64_t vmdelta_us;
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if (active_timers[QEMU_TIMER_REALTIME])
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nearest_delta_us = (active_timers[QEMU_TIMER_REALTIME]->expire_time -
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qemu_get_clock(rt_clock))*1000;
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if (active_timers[QEMU_TIMER_VIRTUAL]) {
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/* round up */
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vmdelta_us = (active_timers[QEMU_TIMER_VIRTUAL]->expire_time -
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qemu_get_clock(vm_clock)+999)/1000;
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if (vmdelta_us < nearest_delta_us)
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nearest_delta_us = vmdelta_us;
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}
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/* Avoid arming the timer to negative, zero, or too low values */
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if (nearest_delta_us <= MIN_TIMER_REARM_US)
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nearest_delta_us = MIN_TIMER_REARM_US;
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return nearest_delta_us;
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}
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#ifndef _WIN32
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#if defined(__linux__)
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@ -1243,6 +1301,80 @@ static void rtc_stop_timer(struct qemu_alarm_timer *t)
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#endif /* !defined(__linux__) */
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static int dynticks_start_timer(struct qemu_alarm_timer *t)
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{
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struct sigevent ev;
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timer_t host_timer;
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struct sigaction act;
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sigfillset(&act.sa_mask);
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act.sa_flags = 0;
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#if defined(TARGET_I386) && defined(USE_CODE_COPY)
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act.sa_flags |= SA_ONSTACK;
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#endif
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act.sa_handler = host_alarm_handler;
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sigaction(SIGALRM, &act, NULL);
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ev.sigev_value.sival_int = 0;
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ev.sigev_notify = SIGEV_SIGNAL;
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ev.sigev_signo = SIGALRM;
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if (timer_create(CLOCK_REALTIME, &ev, &host_timer)) {
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perror("timer_create");
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/* disable dynticks */
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fprintf(stderr, "Dynamic Ticks disabled\n");
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return -1;
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}
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t->priv = (void *)host_timer;
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return 0;
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}
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static void dynticks_stop_timer(struct qemu_alarm_timer *t)
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{
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timer_t host_timer = (timer_t)t->priv;
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timer_delete(host_timer);
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}
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static void dynticks_rearm_timer(struct qemu_alarm_timer *t)
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{
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timer_t host_timer = (timer_t)t->priv;
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struct itimerspec timeout;
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int64_t nearest_delta_us = INT64_MAX;
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int64_t current_us;
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if (!active_timers[QEMU_TIMER_REALTIME] &&
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!active_timers[QEMU_TIMER_VIRTUAL])
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return;
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nearest_delta_us = qemu_next_deadline();
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/* check whether a timer is already running */
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if (timer_gettime(host_timer, &timeout)) {
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perror("gettime");
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fprintf(stderr, "Internal timer error: aborting\n");
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exit(1);
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}
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current_us = timeout.it_value.tv_sec * 1000000 + timeout.it_value.tv_nsec/1000;
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if (current_us && current_us <= nearest_delta_us)
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return;
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timeout.it_interval.tv_sec = 0;
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timeout.it_interval.tv_nsec = 0; /* 0 for one-shot timer */
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timeout.it_value.tv_sec = nearest_delta_us / 1000000;
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timeout.it_value.tv_nsec = (nearest_delta_us % 1000000) * 1000;
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if (timer_settime(host_timer, 0 /* RELATIVE */, &timeout, NULL)) {
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perror("settime");
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fprintf(stderr, "Internal timer error: aborting\n");
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exit(1);
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}
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}
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static int unix_start_timer(struct qemu_alarm_timer *t)
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{
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struct sigaction act;
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@ -1288,6 +1420,7 @@ static int win32_start_timer(struct qemu_alarm_timer *t)
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{
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TIMECAPS tc;
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struct qemu_alarm_win32 *data = t->priv;
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UINT flags;
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data->host_alarm = CreateEvent(NULL, FALSE, FALSE, NULL);
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if (!data->host_alarm) {
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@ -1303,11 +1436,17 @@ static int win32_start_timer(struct qemu_alarm_timer *t)
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timeBeginPeriod(data->period);
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flags = TIME_CALLBACK_FUNCTION;
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if (alarm_has_dynticks(t))
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flags |= TIME_ONESHOT;
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else
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flags |= TIME_PERIODIC;
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data->timerId = timeSetEvent(1, // interval (ms)
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data->period, // resolution
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host_alarm_handler, // function
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(DWORD)t, // parameter
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TIME_PERIODIC | TIME_CALLBACK_FUNCTION);
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flags);
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if (!data->timerId) {
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perror("Failed to initialize win32 alarm timer");
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@ -1332,6 +1471,35 @@ static void win32_stop_timer(struct qemu_alarm_timer *t)
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CloseHandle(data->host_alarm);
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}
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static void win32_rearm_timer(struct qemu_alarm_timer *t)
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{
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struct qemu_alarm_win32 *data = t->priv;
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uint64_t nearest_delta_us;
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if (!active_timers[QEMU_TIMER_REALTIME] &&
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!active_timers[QEMU_TIMER_VIRTUAL])
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return;
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nearest_delta_us = qemu_next_deadline();
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nearest_delta_us /= 1000;
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timeKillEvent(data->timerId);
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data->timerId = timeSetEvent(1,
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data->period,
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host_alarm_handler,
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(DWORD)t,
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TIME_ONESHOT | TIME_PERIODIC);
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if (!data->timerId) {
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perror("Failed to re-arm win32 alarm timer");
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timeEndPeriod(data->period);
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CloseHandle(data->host_alarm);
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exit(1);
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}
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}
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#endif /* _WIN32 */
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static void init_timer_alarm(void)
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@ -6490,6 +6658,7 @@ void vm_start(void)
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cpu_enable_ticks();
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vm_running = 1;
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vm_state_notify(1);
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qemu_rearm_alarm_timer(alarm_timer);
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}
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}
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