diff options
Diffstat (limited to 'qemu-timer.c')
| -rw-r--r-- | qemu-timer.c | 324 |
1 files changed, 259 insertions, 65 deletions
diff --git a/qemu-timer.c b/qemu-timer.c index 50f1943afd..4141b6edbe 100644 --- a/qemu-timer.c +++ b/qemu-timer.c @@ -110,9 +110,12 @@ static int64_t cpu_get_clock(void) } } +#ifndef CONFIG_IOTHREAD static int64_t qemu_icount_delta(void) { - if (use_icount == 1) { + if (!use_icount) { + return 5000 * (int64_t) 1000000; + } else if (use_icount == 1) { /* When not using an adaptive execution frequency we tend to get badly out of sync with real time, so just delay for a reasonable amount of time. */ @@ -121,6 +124,7 @@ static int64_t qemu_icount_delta(void) return cpu_get_icount() - cpu_get_clock(); } } +#endif /* enable cpu_get_ticks() */ void cpu_enable_ticks(void) @@ -153,6 +157,8 @@ void cpu_disable_ticks(void) struct QEMUClock { int type; int enabled; + + QEMUTimer *warp_timer; }; struct QEMUTimer { @@ -169,14 +175,23 @@ struct qemu_alarm_timer { int (*start)(struct qemu_alarm_timer *t); void (*stop)(struct qemu_alarm_timer *t); void (*rearm)(struct qemu_alarm_timer *t); - void *priv; - +#if defined(__linux__) + int fd; + timer_t timer; +#elif defined(_WIN32) + HANDLE timer; +#endif char expired; char pending; }; static struct qemu_alarm_timer *alarm_timer; +static bool qemu_timer_expired_ns(QEMUTimer *timer_head, int64_t current_time) +{ + return timer_head && (timer_head->expire_time <= current_time); +} + int qemu_alarm_pending(void) { return alarm_timer->pending; @@ -200,6 +215,10 @@ static void qemu_rearm_alarm_timer(struct qemu_alarm_timer *t) #ifdef _WIN32 +static int mm_start_timer(struct qemu_alarm_timer *t); +static void mm_stop_timer(struct qemu_alarm_timer *t); +static void mm_rearm_timer(struct qemu_alarm_timer *t); + 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); @@ -284,18 +303,18 @@ static struct qemu_alarm_timer alarm_timers[] = { #ifndef _WIN32 #ifdef __linux__ {"dynticks", dynticks_start_timer, - dynticks_stop_timer, dynticks_rearm_timer, NULL}, + dynticks_stop_timer, dynticks_rearm_timer}, /* HPET - if available - is preferred */ - {"hpet", hpet_start_timer, hpet_stop_timer, NULL, NULL}, + {"hpet", hpet_start_timer, hpet_stop_timer, NULL}, /* ...otherwise try RTC */ - {"rtc", rtc_start_timer, rtc_stop_timer, NULL, NULL}, + {"rtc", rtc_start_timer, rtc_stop_timer, NULL}, #endif - {"unix", unix_start_timer, unix_stop_timer, NULL, NULL}, + {"unix", unix_start_timer, unix_stop_timer, NULL}, #else - {"dynticks", win32_start_timer, - win32_stop_timer, win32_rearm_timer, NULL}, - {"win32", win32_start_timer, - win32_stop_timer, NULL, NULL}, + {"mmtimer", mm_start_timer, mm_stop_timer, NULL}, + {"mmtimer2", mm_start_timer, mm_stop_timer, mm_rearm_timer}, + {"dynticks", win32_start_timer, win32_stop_timer, win32_rearm_timer}, + {"win32", win32_start_timer, win32_stop_timer, NULL}, #endif {NULL, } }; @@ -386,6 +405,90 @@ void qemu_clock_enable(QEMUClock *clock, int enabled) clock->enabled = enabled; } +static int64_t vm_clock_warp_start; + +static void icount_warp_rt(void *opaque) +{ + if (vm_clock_warp_start == -1) { + return; + } + + if (vm_running) { + int64_t clock = qemu_get_clock_ns(rt_clock); + int64_t warp_delta = clock - vm_clock_warp_start; + if (use_icount == 1) { + qemu_icount_bias += warp_delta; + } else { + /* + * In adaptive mode, do not let the vm_clock run too + * far ahead of real time. + */ + int64_t cur_time = cpu_get_clock(); + int64_t cur_icount = qemu_get_clock_ns(vm_clock); + int64_t delta = cur_time - cur_icount; + qemu_icount_bias += MIN(warp_delta, delta); + } + if (qemu_timer_expired(active_timers[QEMU_CLOCK_VIRTUAL], + qemu_get_clock_ns(vm_clock))) { + qemu_notify_event(); + } + } + vm_clock_warp_start = -1; +} + +void qemu_clock_warp(QEMUClock *clock) +{ + int64_t deadline; + + if (!clock->warp_timer) { + return; + } + + /* + * There are too many global variables to make the "warp" behavior + * applicable to other clocks. But a clock argument removes the + * need for if statements all over the place. + */ + assert(clock == vm_clock); + + /* + * If the CPUs have been sleeping, advance the vm_clock timer now. This + * ensures that the deadline for the timer is computed correctly below. + * This also makes sure that the insn counter is synchronized before the + * CPU starts running, in case the CPU is woken by an event other than + * the earliest vm_clock timer. + */ + icount_warp_rt(NULL); + if (!all_cpu_threads_idle() || !active_timers[clock->type]) { + qemu_del_timer(clock->warp_timer); + return; + } + + vm_clock_warp_start = qemu_get_clock_ns(rt_clock); + deadline = qemu_next_icount_deadline(); + if (deadline > 0) { + /* + * Ensure the vm_clock proceeds even when the virtual CPU goes to + * sleep. Otherwise, the CPU might be waiting for a future timer + * interrupt to wake it up, but the interrupt never comes because + * the vCPU isn't running any insns and thus doesn't advance the + * vm_clock. + * + * An extreme solution for this problem would be to never let VCPUs + * sleep in icount mode if there is a pending vm_clock timer; rather + * time could just advance to the next vm_clock event. Instead, we + * do stop VCPUs and only advance vm_clock after some "real" time, + * (related to the time left until the next event) has passed. This + * rt_clock timer will do this. This avoids that the warps are too + * visible externally---for example, you will not be sending network + * packets continously instead of every 100ms. + */ + qemu_mod_timer(clock->warp_timer, vm_clock_warp_start + deadline); + } else { + qemu_notify_event(); + } +} + QEMUTimer *qemu_new_timer(QEMUClock *clock, int scale, QEMUTimerCB *cb, void *opaque) { @@ -438,10 +541,9 @@ static void qemu_mod_timer_ns(QEMUTimer *ts, int64_t expire_time) pt = &active_timers[ts->clock->type]; for(;;) { t = *pt; - if (!t) - break; - if (t->expire_time > expire_time) + if (!qemu_timer_expired_ns(t, expire_time)) { break; + } pt = &t->next; } ts->expire_time = expire_time; @@ -454,8 +556,10 @@ static void qemu_mod_timer_ns(QEMUTimer *ts, int64_t expire_time) qemu_rearm_alarm_timer(alarm_timer); } /* Interrupt execution to force deadline recalculation. */ - if (use_icount) + qemu_clock_warp(ts->clock); + if (use_icount) { qemu_notify_event(); + } } } @@ -478,9 +582,7 @@ int qemu_timer_pending(QEMUTimer *ts) int qemu_timer_expired(QEMUTimer *timer_head, int64_t current_time) { - if (!timer_head) - return 0; - return (timer_head->expire_time <= current_time * timer_head->scale); + return qemu_timer_expired_ns(timer_head, current_time * timer_head->scale); } static void qemu_run_timers(QEMUClock *clock) @@ -495,8 +597,9 @@ static void qemu_run_timers(QEMUClock *clock) ptimer_head = &active_timers[clock->type]; for(;;) { ts = *ptimer_head; - if (!ts || ts->expire_time > current_time) + if (!qemu_timer_expired_ns(ts, current_time)) { break; + } /* remove timer from the list before calling the callback */ *ptimer_head = ts->next; ts->next = NULL; @@ -576,6 +679,10 @@ void configure_icount(const char *option) if (!option) return; +#ifdef CONFIG_IOTHREAD + vm_clock->warp_timer = qemu_new_timer_ns(rt_clock, icount_warp_rt, NULL); +#endif + if (strcmp(option, "auto") != 0) { icount_time_shift = strtol(option, NULL, 0); use_icount = 1; @@ -669,21 +776,16 @@ static void host_alarm_handler(int host_signum) } } -int64_t qemu_next_deadline(void) +int64_t qemu_next_icount_deadline(void) { /* To avoid problems with overflow limit this to 2^32. */ int64_t delta = INT32_MAX; + assert(use_icount); if (active_timers[QEMU_CLOCK_VIRTUAL]) { delta = active_timers[QEMU_CLOCK_VIRTUAL]->expire_time - qemu_get_clock_ns(vm_clock); } - if (active_timers[QEMU_CLOCK_HOST]) { - int64_t hdelta = active_timers[QEMU_CLOCK_HOST]->expire_time - - qemu_get_clock_ns(host_clock); - if (hdelta < delta) - delta = hdelta; - } if (delta < 0) delta = 0; @@ -770,7 +872,7 @@ static int hpet_start_timer(struct qemu_alarm_timer *t) goto fail; enable_sigio_timer(fd); - t->priv = (void *)(long)fd; + t->fd = fd; return 0; fail: @@ -780,7 +882,7 @@ fail: static void hpet_stop_timer(struct qemu_alarm_timer *t) { - int fd = (long)t->priv; + int fd = t->fd; close(fd); } @@ -809,14 +911,14 @@ static int rtc_start_timer(struct qemu_alarm_timer *t) enable_sigio_timer(rtc_fd); - t->priv = (void *)(long)rtc_fd; + t->fd = rtc_fd; return 0; } static void rtc_stop_timer(struct qemu_alarm_timer *t) { - int rtc_fd = (long)t->priv; + int rtc_fd = t->fd; close(rtc_fd); } @@ -851,21 +953,21 @@ static int dynticks_start_timer(struct qemu_alarm_timer *t) return -1; } - t->priv = (void *)(long)host_timer; + t->timer = host_timer; return 0; } static void dynticks_stop_timer(struct qemu_alarm_timer *t) { - timer_t host_timer = (timer_t)(long)t->priv; + timer_t host_timer = t->timer; timer_delete(host_timer); } static void dynticks_rearm_timer(struct qemu_alarm_timer *t) { - timer_t host_timer = (timer_t)(long)t->priv; + timer_t host_timer = t->timer; struct itimerspec timeout; int64_t nearest_delta_ns = INT64_MAX; int64_t current_ns; @@ -944,6 +1046,96 @@ static void unix_stop_timer(struct qemu_alarm_timer *t) #ifdef _WIN32 +static MMRESULT mm_timer; +static unsigned mm_period; + +static void CALLBACK mm_alarm_handler(UINT uTimerID, UINT uMsg, + DWORD_PTR dwUser, DWORD_PTR dw1, + DWORD_PTR dw2) +{ + struct qemu_alarm_timer *t = alarm_timer; + if (!t) { + return; + } + if (alarm_has_dynticks(t) || qemu_next_alarm_deadline() <= 0) { + t->expired = alarm_has_dynticks(t); + t->pending = 1; + qemu_notify_event(); + } +} + +static int mm_start_timer(struct qemu_alarm_timer *t) +{ + TIMECAPS tc; + UINT flags; + + memset(&tc, 0, sizeof(tc)); + timeGetDevCaps(&tc, sizeof(tc)); + + mm_period = tc.wPeriodMin; + timeBeginPeriod(mm_period); + + flags = TIME_CALLBACK_FUNCTION; + if (alarm_has_dynticks(t)) { + flags |= TIME_ONESHOT; + } else { + flags |= TIME_PERIODIC; + } + + mm_timer = timeSetEvent(1, /* interval (ms) */ + mm_period, /* resolution */ + mm_alarm_handler, /* function */ + (DWORD_PTR)t, /* parameter */ + flags); + + if (!mm_timer) { + fprintf(stderr, "Failed to initialize win32 alarm timer: %ld\n", + GetLastError()); + timeEndPeriod(mm_period); + return -1; + } + + return 0; +} + +static void mm_stop_timer(struct qemu_alarm_timer *t) +{ + timeKillEvent(mm_timer); + timeEndPeriod(mm_period); +} + +static void mm_rearm_timer(struct qemu_alarm_timer *t) +{ + int nearest_delta_ms; + + assert(alarm_has_dynticks(t)); + if (!active_timers[QEMU_CLOCK_REALTIME] && + !active_timers[QEMU_CLOCK_VIRTUAL] && + !active_timers[QEMU_CLOCK_HOST]) { + return; + } + + timeKillEvent(mm_timer); + + nearest_delta_ms = (qemu_next_alarm_deadline() + 999999) / 1000000; + if (nearest_delta_ms < 1) { + nearest_delta_ms = 1; + } + mm_timer = timeSetEvent(nearest_delta_ms, + mm_period, + mm_alarm_handler, + (DWORD_PTR)t, + TIME_ONESHOT | TIME_CALLBACK_FUNCTION); + + if (!mm_timer) { + fprintf(stderr, "Failed to re-arm win32 alarm timer %ld\n", + GetLastError()); + + timeEndPeriod(mm_period); + exit(1); + } +} + static int win32_start_timer(struct qemu_alarm_timer *t) { HANDLE hTimer; @@ -967,13 +1159,13 @@ static int win32_start_timer(struct qemu_alarm_timer *t) return -1; } - t->priv = (PVOID) hTimer; + t->timer = hTimer; return 0; } static void win32_stop_timer(struct qemu_alarm_timer *t) { - HANDLE hTimer = t->priv; + HANDLE hTimer = t->timer; if (hTimer) { DeleteTimerQueueTimer(NULL, hTimer, NULL); @@ -982,7 +1174,7 @@ static void win32_stop_timer(struct qemu_alarm_timer *t) static void win32_rearm_timer(struct qemu_alarm_timer *t) { - HANDLE hTimer = t->priv; + HANDLE hTimer = t->timer; int nearest_delta_ms; BOOLEAN success; @@ -1055,39 +1247,41 @@ void quit_timers(void) int qemu_calculate_timeout(void) { +#ifndef CONFIG_IOTHREAD int timeout; - int64_t add; - int64_t delta; - /* When using icount, making forward progress with qemu_icount when the - guest CPU is idle is critical. We only use the static io-thread timeout - for non icount runs. */ - if (!use_icount || !vm_running) { - return 5000; - } - - /* Advance virtual time to the next event. */ - delta = qemu_icount_delta(); - if (delta > 0) { - /* If virtual time is ahead of real time then just - wait for IO. */ - timeout = (delta + 999999) / 1000000; - } else { - /* Wait for either IO to occur or the next - timer event. */ - add = qemu_next_deadline(); - /* We advance the timer before checking for IO. - Limit the amount we advance so that early IO - activity won't get the guest too far ahead. */ - if (add > 10000000) - add = 10000000; - delta += add; - qemu_icount += qemu_icount_round (add); - timeout = delta / 1000000; - if (timeout < 0) - timeout = 0; + if (!vm_running) + timeout = 5000; + else { + /* XXX: use timeout computed from timers */ + int64_t add; + int64_t delta; + /* Advance virtual time to the next event. */ + delta = qemu_icount_delta(); + if (delta > 0) { + /* If virtual time is ahead of real time then just + wait for IO. */ + timeout = (delta + 999999) / 1000000; + } else { + /* Wait for either IO to occur or the next + timer event. */ + add = qemu_next_icount_deadline(); + /* We advance the timer before checking for IO. + Limit the amount we advance so that early IO + activity won't get the guest too far ahead. */ + if (add > 10000000) + add = 10000000; + delta += add; + qemu_icount += qemu_icount_round (add); + timeout = delta / 1000000; + if (timeout < 0) + timeout = 0; + } } return timeout; +#else /* CONFIG_IOTHREAD */ + return 1000; +#endif } |