diff options
| -rw-r--r-- | cpus.c | 28 | ||||
| -rw-r--r-- | include/qemu/timer.h | 24 | ||||
| -rw-r--r-- | util/qemu-timer.c | 4 |
3 files changed, 52 insertions, 4 deletions
@@ -800,9 +800,25 @@ static void qemu_cpu_kick_rr_cpu(void) } while (cpu != atomic_mb_read(&tcg_current_rr_cpu)); } +static void do_nothing(CPUState *cpu, run_on_cpu_data unused) +{ +} + void qemu_timer_notify_cb(void *opaque, QEMUClockType type) { - qemu_notify_event(); + if (!use_icount || type != QEMU_CLOCK_VIRTUAL) { + qemu_notify_event(); + return; + } + + if (!qemu_in_vcpu_thread() && first_cpu) { + /* qemu_cpu_kick is not enough to kick a halted CPU out of + * qemu_tcg_wait_io_event. async_run_on_cpu, instead, + * causes cpu_thread_is_idle to return false. This way, + * handle_icount_deadline can run. + */ + async_run_on_cpu(first_cpu, do_nothing, RUN_ON_CPU_NULL); + } } static void kick_tcg_thread(void *opaque) @@ -1150,12 +1166,15 @@ static int64_t tcg_get_icount_limit(void) static void handle_icount_deadline(void) { + assert(qemu_in_vcpu_thread()); if (use_icount) { int64_t deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL); if (deadline == 0) { + /* Wake up other AioContexts. */ qemu_clock_notify(QEMU_CLOCK_VIRTUAL); + qemu_clock_run_timers(QEMU_CLOCK_VIRTUAL); } } } @@ -1268,6 +1287,11 @@ static void *qemu_tcg_rr_cpu_thread_fn(void *arg) /* Account partial waits to QEMU_CLOCK_VIRTUAL. */ qemu_account_warp_timer(); + /* Run the timers here. This is much more efficient than + * waking up the I/O thread and waiting for completion. + */ + handle_icount_deadline(); + if (!cpu) { cpu = first_cpu; } @@ -1309,8 +1333,6 @@ static void *qemu_tcg_rr_cpu_thread_fn(void *arg) atomic_mb_set(&cpu->exit_request, 0); } - handle_icount_deadline(); - qemu_tcg_wait_io_event(cpu ? cpu : QTAILQ_FIRST(&cpus)); deal_with_unplugged_cpus(); } diff --git a/include/qemu/timer.h b/include/qemu/timer.h index 1441b426cd..e1742f2f3d 100644 --- a/include/qemu/timer.h +++ b/include/qemu/timer.h @@ -533,6 +533,12 @@ static inline QEMUTimer *timer_new_tl(QEMUTimerList *timer_list, * Create a new timer and associate it with the default * timer list for the clock type @type. * + * The default timer list has one special feature: in icount mode, + * %QEMU_CLOCK_VIRTUAL timers are run in the vCPU thread. This is + * not true of other timer lists, which are typically associated + * with an AioContext---each of them runs its timer callbacks in its own + * AioContext thread. + * * Returns: a pointer to the timer */ static inline QEMUTimer *timer_new(QEMUClockType type, int scale, @@ -550,6 +556,12 @@ static inline QEMUTimer *timer_new(QEMUClockType type, int scale, * Create a new timer with nanosecond scale on the default timer list * associated with the clock. * + * The default timer list has one special feature: in icount mode, + * %QEMU_CLOCK_VIRTUAL timers are run in the vCPU thread. This is + * not true of other timer lists, which are typically associated + * with an AioContext---each of them runs its timer callbacks in its own + * AioContext thread. + * * Returns: a pointer to the newly created timer */ static inline QEMUTimer *timer_new_ns(QEMUClockType type, QEMUTimerCB *cb, @@ -564,6 +576,12 @@ static inline QEMUTimer *timer_new_ns(QEMUClockType type, QEMUTimerCB *cb, * @cb: the callback to call when the timer expires * @opaque: the opaque pointer to pass to the callback * + * The default timer list has one special feature: in icount mode, + * %QEMU_CLOCK_VIRTUAL timers are run in the vCPU thread. This is + * not true of other timer lists, which are typically associated + * with an AioContext---each of them runs its timer callbacks in its own + * AioContext thread. + * * Create a new timer with microsecond scale on the default timer list * associated with the clock. * @@ -581,6 +599,12 @@ static inline QEMUTimer *timer_new_us(QEMUClockType type, QEMUTimerCB *cb, * @cb: the callback to call when the timer expires * @opaque: the opaque pointer to pass to the callback * + * The default timer list has one special feature: in icount mode, + * %QEMU_CLOCK_VIRTUAL timers are run in the vCPU thread. This is + * not true of other timer lists, which are typically associated + * with an AioContext---each of them runs its timer callbacks in its own + * AioContext thread. + * * Create a new timer with millisecond scale on the default timer list * associated with the clock. * diff --git a/util/qemu-timer.c b/util/qemu-timer.c index dc3181e9b8..82d56507a2 100644 --- a/util/qemu-timer.c +++ b/util/qemu-timer.c @@ -658,7 +658,9 @@ bool qemu_clock_run_all_timers(void) QEMUClockType type; for (type = 0; type < QEMU_CLOCK_MAX; type++) { - progress |= qemu_clock_run_timers(type); + if (qemu_clock_use_for_deadline(type)) { + progress |= qemu_clock_run_timers(type); + } } return progress; |