diff options
author | Paolo Bonzini <pbonzini@redhat.com> | 2011-09-12 13:57:37 +0200 |
---|---|---|
committer | Paolo Bonzini <pbonzini@redhat.com> | 2011-10-21 18:14:30 +0200 |
commit | 946fb27c1dc158f10a6e3ce0374a161dce04c27b (patch) | |
tree | 1825f63a5fff335fd8b43980261fb4551a8193ba /qemu-timer.c | |
parent | dc2dfcf0002b4e6be494959a1ed2589dd109def0 (diff) |
qemu-timer: move icount to cpus.c
None of this is needed by tools, and most of it can even be made static
inside cpus.c.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'qemu-timer.c')
-rw-r--r-- | qemu-timer.c | 279 |
1 files changed, 0 insertions, 279 deletions
diff --git a/qemu-timer.c b/qemu-timer.c index ebb50890e..8129af6ed 100644 --- a/qemu-timer.c +++ b/qemu-timer.c @@ -46,82 +46,6 @@ #include "qemu-timer.h" -/* Conversion factor from emulated instructions to virtual clock ticks. */ -int icount_time_shift; -/* Arbitrarily pick 1MIPS as the minimum allowable speed. */ -#define MAX_ICOUNT_SHIFT 10 -/* Compensate for varying guest execution speed. */ -int64_t qemu_icount_bias; -static QEMUTimer *icount_rt_timer; -static QEMUTimer *icount_vm_timer; - -/***********************************************************/ -/* guest cycle counter */ - -typedef struct TimersState { - int64_t cpu_ticks_prev; - int64_t cpu_ticks_offset; - int64_t cpu_clock_offset; - int32_t cpu_ticks_enabled; - int64_t dummy; -} TimersState; - -TimersState timers_state; - -/* return the host CPU cycle counter and handle stop/restart */ -int64_t cpu_get_ticks(void) -{ - if (use_icount) { - return cpu_get_icount(); - } - if (!timers_state.cpu_ticks_enabled) { - return timers_state.cpu_ticks_offset; - } else { - int64_t ticks; - ticks = cpu_get_real_ticks(); - if (timers_state.cpu_ticks_prev > ticks) { - /* Note: non increasing ticks may happen if the host uses - software suspend */ - timers_state.cpu_ticks_offset += timers_state.cpu_ticks_prev - ticks; - } - timers_state.cpu_ticks_prev = ticks; - return ticks + timers_state.cpu_ticks_offset; - } -} - -/* return the host CPU monotonic timer and handle stop/restart */ -static int64_t cpu_get_clock(void) -{ - int64_t ti; - if (!timers_state.cpu_ticks_enabled) { - return timers_state.cpu_clock_offset; - } else { - ti = get_clock(); - return ti + timers_state.cpu_clock_offset; - } -} - -/* enable cpu_get_ticks() */ -void cpu_enable_ticks(void) -{ - if (!timers_state.cpu_ticks_enabled) { - timers_state.cpu_ticks_offset -= cpu_get_real_ticks(); - timers_state.cpu_clock_offset -= get_clock(); - timers_state.cpu_ticks_enabled = 1; - } -} - -/* disable cpu_get_ticks() : the clock is stopped. You must not call - cpu_get_ticks() after that. */ -void cpu_disable_ticks(void) -{ - if (timers_state.cpu_ticks_enabled) { - timers_state.cpu_ticks_offset = cpu_get_ticks(); - timers_state.cpu_clock_offset = cpu_get_clock(); - timers_state.cpu_ticks_enabled = 0; - } -} - /***********************************************************/ /* timers */ @@ -133,7 +57,6 @@ struct QEMUClock { int type; int enabled; - QEMUTimer *warp_timer; QEMUTimer *active_timers; NotifierList reset_notifiers; @@ -252,61 +175,6 @@ static void dynticks_rearm_timer(struct qemu_alarm_timer *t, int64_t delta); #endif /* _WIN32 */ -/* Correlation between real and virtual time is always going to be - fairly approximate, so ignore small variation. - When the guest is idle real and virtual time will be aligned in - the IO wait loop. */ -#define ICOUNT_WOBBLE (get_ticks_per_sec() / 10) - -static void icount_adjust(void) -{ - int64_t cur_time; - int64_t cur_icount; - int64_t delta; - static int64_t last_delta; - /* If the VM is not running, then do nothing. */ - if (!runstate_is_running()) - return; - - cur_time = cpu_get_clock(); - cur_icount = qemu_get_clock_ns(vm_clock); - delta = cur_icount - cur_time; - /* FIXME: This is a very crude algorithm, somewhat prone to oscillation. */ - if (delta > 0 - && last_delta + ICOUNT_WOBBLE < delta * 2 - && icount_time_shift > 0) { - /* The guest is getting too far ahead. Slow time down. */ - icount_time_shift--; - } - if (delta < 0 - && last_delta - ICOUNT_WOBBLE > delta * 2 - && icount_time_shift < MAX_ICOUNT_SHIFT) { - /* The guest is getting too far behind. Speed time up. */ - icount_time_shift++; - } - last_delta = delta; - qemu_icount_bias = cur_icount - (qemu_icount << icount_time_shift); -} - -static void icount_adjust_rt(void * opaque) -{ - qemu_mod_timer(icount_rt_timer, - qemu_get_clock_ms(rt_clock) + 1000); - icount_adjust(); -} - -static void icount_adjust_vm(void * opaque) -{ - qemu_mod_timer(icount_vm_timer, - qemu_get_clock_ns(vm_clock) + get_ticks_per_sec() / 10); - icount_adjust(); -} - -int64_t qemu_icount_round(int64_t count) -{ - return (count + (1 << icount_time_shift) - 1) >> icount_time_shift; -} - static struct qemu_alarm_timer alarm_timers[] = { #ifndef _WIN32 #ifdef __linux__ @@ -411,90 +279,6 @@ 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 (runstate_is_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(vm_clock->active_timers, - 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() || !clock->active_timers) { - 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(); - } -} - int64_t qemu_clock_has_timers(QEMUClock *clock) { return !!clock->active_timers; @@ -709,52 +493,6 @@ void qemu_get_timer(QEMUFile *f, QEMUTimer *ts) } } -static const VMStateDescription vmstate_timers = { - .name = "timer", - .version_id = 2, - .minimum_version_id = 1, - .minimum_version_id_old = 1, - .fields = (VMStateField []) { - VMSTATE_INT64(cpu_ticks_offset, TimersState), - VMSTATE_INT64(dummy, TimersState), - VMSTATE_INT64_V(cpu_clock_offset, TimersState, 2), - VMSTATE_END_OF_LIST() - } -}; - -void configure_icount(const char *option) -{ - vmstate_register(NULL, 0, &vmstate_timers, &timers_state); - if (!option) - return; - - vm_clock->warp_timer = qemu_new_timer_ns(rt_clock, icount_warp_rt, NULL); - - if (strcmp(option, "auto") != 0) { - icount_time_shift = strtol(option, NULL, 0); - use_icount = 1; - return; - } - - use_icount = 2; - - /* 125MIPS seems a reasonable initial guess at the guest speed. - It will be corrected fairly quickly anyway. */ - icount_time_shift = 3; - - /* Have both realtime and virtual time triggers for speed adjustment. - The realtime trigger catches emulated time passing too slowly, - the virtual time trigger catches emulated time passing too fast. - Realtime triggers occur even when idle, so use them less frequently - than VM triggers. */ - icount_rt_timer = qemu_new_timer_ms(rt_clock, icount_adjust_rt, NULL); - qemu_mod_timer(icount_rt_timer, - qemu_get_clock_ms(rt_clock) + 1000); - icount_vm_timer = qemu_new_timer_ns(vm_clock, icount_adjust_vm, NULL); - qemu_mod_timer(icount_vm_timer, - qemu_get_clock_ns(vm_clock) + get_ticks_per_sec() / 10); -} - void qemu_run_all_timers(void) { alarm_timer->pending = 0; @@ -821,23 +559,6 @@ static void host_alarm_handler(int host_signum) } } -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 (vm_clock->active_timers) { - delta = vm_clock->active_timers->expire_time - - qemu_get_clock_ns(vm_clock); - } - - if (delta < 0) - delta = 0; - - return delta; -} - #if defined(__linux__) #include "compatfd.h" |