Commit efe75411 authored by ths's avatar ths

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
parent f3dcfada
......@@ -784,12 +784,32 @@ struct QEMUTimer {
struct qemu_alarm_timer {
char const *name;
unsigned int flags;
int (*start)(struct qemu_alarm_timer *t);
void (*stop)(struct qemu_alarm_timer *t);
void (*rearm)(struct qemu_alarm_timer *t);
void *priv;
};
#define ALARM_FLAG_DYNTICKS 0x1
static inline int alarm_has_dynticks(struct qemu_alarm_timer *t)
{
return t->flags & ALARM_FLAG_DYNTICKS;
}
static void qemu_rearm_alarm_timer(struct qemu_alarm_timer *t)
{
if (!alarm_has_dynticks(t))
return;
t->rearm(t);
}
/* TODO: MIN_TIMER_REARM_US should be optimized */
#define MIN_TIMER_REARM_US 250
static struct qemu_alarm_timer *alarm_timer;
#ifdef _WIN32
......@@ -802,12 +822,17 @@ struct qemu_alarm_win32 {
static int win32_start_timer(struct qemu_alarm_timer *t);
static void win32_stop_timer(struct qemu_alarm_timer *t);
static void win32_rearm_timer(struct qemu_alarm_timer *t);
#else
static int unix_start_timer(struct qemu_alarm_timer *t);
static void unix_stop_timer(struct qemu_alarm_timer *t);
static int dynticks_start_timer(struct qemu_alarm_timer *t);
static void dynticks_stop_timer(struct qemu_alarm_timer *t);
static void dynticks_rearm_timer(struct qemu_alarm_timer *t);
#ifdef __linux__
static int hpet_start_timer(struct qemu_alarm_timer *t);
......@@ -816,21 +841,26 @@ static void hpet_stop_timer(struct qemu_alarm_timer *t);
static int rtc_start_timer(struct qemu_alarm_timer *t);
static void rtc_stop_timer(struct qemu_alarm_timer *t);
#endif
#endif /* __linux__ */
#endif /* _WIN32 */
static struct qemu_alarm_timer alarm_timers[] = {
#ifndef _WIN32
{"dynticks", ALARM_FLAG_DYNTICKS, dynticks_start_timer,
dynticks_stop_timer, dynticks_rearm_timer, NULL},
#ifdef __linux__
/* HPET - if available - is preferred */
{"hpet", hpet_start_timer, hpet_stop_timer, NULL},
{"hpet", 0, hpet_start_timer, hpet_stop_timer, NULL, NULL},
/* ...otherwise try RTC */
{"rtc", rtc_start_timer, rtc_stop_timer, NULL},
{"rtc", 0, rtc_start_timer, rtc_stop_timer, NULL, NULL},
#endif
#ifndef _WIN32
{"unix", unix_start_timer, unix_stop_timer, NULL},
{"unix", 0, unix_start_timer, unix_stop_timer, NULL, NULL},
#else
{"win32", win32_start_timer, win32_stop_timer, &alarm_win32_data},
{"dynticks", ALARM_FLAG_DYNTICKS, win32_start_timer,
win32_stop_timer, win32_rearm_timer, &alarm_win32_data},
{"win32", 0, win32_start_timer,
win32_stop_timer, NULL, &alarm_win32_data},
#endif
{NULL, }
};
......@@ -949,6 +979,8 @@ void qemu_del_timer(QEMUTimer *ts)
}
pt = &t->next;
}
qemu_rearm_alarm_timer(alarm_timer);
}
/* modify the current timer so that it will be fired when current_time
......@@ -1008,6 +1040,7 @@ static void qemu_run_timers(QEMUTimer **ptimer_head, int64_t current_time)
/* run the callback (the timer list can be modified) */
ts->cb(ts->opaque);
}
qemu_rearm_alarm_timer(alarm_timer);
}
int64_t qemu_get_clock(QEMUClock *clock)
......@@ -1115,7 +1148,8 @@ static void host_alarm_handler(int host_signum)
last_clock = ti;
}
#endif
if (qemu_timer_expired(active_timers[QEMU_TIMER_VIRTUAL],
if (alarm_has_dynticks(alarm_timer) ||
qemu_timer_expired(active_timers[QEMU_TIMER_VIRTUAL],
qemu_get_clock(vm_clock)) ||
qemu_timer_expired(active_timers[QEMU_TIMER_REALTIME],
qemu_get_clock(rt_clock))) {
......@@ -1136,6 +1170,30 @@ static void host_alarm_handler(int host_signum)
}
}
static uint64_t qemu_next_deadline(void)
{
int64_t nearest_delta_us = ULLONG_MAX;
int64_t vmdelta_us;
if (active_timers[QEMU_TIMER_REALTIME])
nearest_delta_us = (active_timers[QEMU_TIMER_REALTIME]->expire_time -
qemu_get_clock(rt_clock))*1000;
if (active_timers[QEMU_TIMER_VIRTUAL]) {
/* round up */
vmdelta_us = (active_timers[QEMU_TIMER_VIRTUAL]->expire_time -
qemu_get_clock(vm_clock)+999)/1000;
if (vmdelta_us < nearest_delta_us)
nearest_delta_us = vmdelta_us;
}
/* Avoid arming the timer to negative, zero, or too low values */
if (nearest_delta_us <= MIN_TIMER_REARM_US)
nearest_delta_us = MIN_TIMER_REARM_US;
return nearest_delta_us;
}
#ifndef _WIN32
#if defined(__linux__)
......@@ -1243,6 +1301,80 @@ static void rtc_stop_timer(struct qemu_alarm_timer *t)
#endif /* !defined(__linux__) */
static int dynticks_start_timer(struct qemu_alarm_timer *t)
{
struct sigevent ev;
timer_t host_timer;
struct sigaction act;
sigfillset(&act.sa_mask);
act.sa_flags = 0;
#if defined(TARGET_I386) && defined(USE_CODE_COPY)
act.sa_flags |= SA_ONSTACK;
#endif
act.sa_handler = host_alarm_handler;
sigaction(SIGALRM, &act, NULL);
ev.sigev_value.sival_int = 0;
ev.sigev_notify = SIGEV_SIGNAL;
ev.sigev_signo = SIGALRM;
if (timer_create(CLOCK_REALTIME, &ev, &host_timer)) {
perror("timer_create");
/* disable dynticks */
fprintf(stderr, "Dynamic Ticks disabled\n");
return -1;
}
t->priv = (void *)host_timer;
return 0;
}
static void dynticks_stop_timer(struct qemu_alarm_timer *t)
{
timer_t host_timer = (timer_t)t->priv;
timer_delete(host_timer);
}
static void dynticks_rearm_timer(struct qemu_alarm_timer *t)
{
timer_t host_timer = (timer_t)t->priv;
struct itimerspec timeout;
int64_t nearest_delta_us = INT64_MAX;
int64_t current_us;
if (!active_timers[QEMU_TIMER_REALTIME] &&
!active_timers[QEMU_TIMER_VIRTUAL])
return;
nearest_delta_us = qemu_next_deadline();
/* check whether a timer is already running */
if (timer_gettime(host_timer, &timeout)) {
perror("gettime");
fprintf(stderr, "Internal timer error: aborting\n");
exit(1);
}
current_us = timeout.it_value.tv_sec * 1000000 + timeout.it_value.tv_nsec/1000;
if (current_us && current_us <= nearest_delta_us)
return;
timeout.it_interval.tv_sec = 0;
timeout.it_interval.tv_nsec = 0; /* 0 for one-shot timer */
timeout.it_value.tv_sec = nearest_delta_us / 1000000;
timeout.it_value.tv_nsec = (nearest_delta_us % 1000000) * 1000;
if (timer_settime(host_timer, 0 /* RELATIVE */, &timeout, NULL)) {
perror("settime");
fprintf(stderr, "Internal timer error: aborting\n");
exit(1);
}
}
static int unix_start_timer(struct qemu_alarm_timer *t)
{
struct sigaction act;
......@@ -1288,6 +1420,7 @@ static int win32_start_timer(struct qemu_alarm_timer *t)
{
TIMECAPS tc;
struct qemu_alarm_win32 *data = t->priv;
UINT flags;
data->host_alarm = CreateEvent(NULL, FALSE, FALSE, NULL);
if (!data->host_alarm) {
......@@ -1303,11 +1436,17 @@ static int win32_start_timer(struct qemu_alarm_timer *t)
timeBeginPeriod(data->period);
flags = TIME_CALLBACK_FUNCTION;
if (alarm_has_dynticks(t))
flags |= TIME_ONESHOT;
else
flags |= TIME_PERIODIC;
data->timerId = timeSetEvent(1, // interval (ms)
data->period, // resolution
host_alarm_handler, // function
(DWORD)t, // parameter
TIME_PERIODIC | TIME_CALLBACK_FUNCTION);
flags);
if (!data->timerId) {
perror("Failed to initialize win32 alarm timer");
......@@ -1332,6 +1471,35 @@ static void win32_stop_timer(struct qemu_alarm_timer *t)
CloseHandle(data->host_alarm);
}
static void win32_rearm_timer(struct qemu_alarm_timer *t)
{
struct qemu_alarm_win32 *data = t->priv;
uint64_t nearest_delta_us;
if (!active_timers[QEMU_TIMER_REALTIME] &&
!active_timers[QEMU_TIMER_VIRTUAL])
return;
nearest_delta_us = qemu_next_deadline();
nearest_delta_us /= 1000;
timeKillEvent(data->timerId);
data->timerId = timeSetEvent(1,
data->period,
host_alarm_handler,
(DWORD)t,
TIME_ONESHOT | TIME_PERIODIC);
if (!data->timerId) {
perror("Failed to re-arm win32 alarm timer");
timeEndPeriod(data->period);
CloseHandle(data->host_alarm);
exit(1);
}
}
#endif /* _WIN32 */
static void init_timer_alarm(void)
......@@ -6490,6 +6658,7 @@ void vm_start(void)
cpu_enable_ticks();
vm_running = 1;
vm_state_notify(1);
qemu_rearm_alarm_timer(alarm_timer);
}
}
......
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