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Timers: Better predict next event time

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Significantly improves performance in Fromage.
This commit is contained in:
Connor McLaughlin 2021-02-19 17:10:59 +10:00
parent caae06dbf4
commit ae49215251
1 changed files with 19 additions and 19 deletions
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38
src/core/timers.cpp
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@ -355,41 +355,41 @@ void Timers::UpdateIRQ(u32 index)
TickCount Timers::GetTicksUntilNextInterrupt() const TickCount Timers::GetTicksUntilNextInterrupt() const
{ {
TickCount min_ticks = std::numeric_limits<TickCount>::max(); TickCount min_ticks = System::GetMaxSliceTicks();
for (u32 i = 0; i < NUM_TIMERS; i++) for (u32 i = 0; i < NUM_TIMERS; i++)
{ {
const CounterState& cs = m_states[i]; const CounterState& cs = m_states[i];
if (!cs.counting_enabled || (i < 2 && cs.external_counting_enabled) || if (!cs.counting_enabled || (i < 2 && cs.external_counting_enabled) ||
(!cs.mode.irq_at_target && !cs.mode.irq_on_overflow)) (!cs.mode.irq_at_target && !cs.mode.irq_on_overflow && (cs.mode.irq_repeat || !cs.irq_done)))
{ {
continue; continue;
} }
TickCount min_ticks_for_this_timer = std::numeric_limits<TickCount>::max(); if (cs.mode.irq_at_target)
if (cs.mode.irq_at_target && cs.counter < cs.target) {
min_ticks_for_this_timer = static_cast<TickCount>(cs.target - cs.counter); TickCount ticks = (cs.counter <= cs.target) ? static_cast<TickCount>(cs.target - cs.counter) :
if (cs.mode.irq_on_overflow && cs.counter < cs.target) static_cast<TickCount>((0xFFFFu - cs.counter) + cs.target);
min_ticks_for_this_timer = std::min(min_ticks_for_this_timer, static_cast<TickCount>(0xFFFF - cs.counter));
if (cs.external_counting_enabled) // sysclk/8 for timer 2 if (cs.external_counting_enabled) // sysclk/8 for timer 2
min_ticks_for_this_timer = std::max<TickCount>(1, System::ScaleTicksToOverclock(min_ticks_for_this_timer * 8)); ticks *= 8;
else
min_ticks_for_this_timer = std::max<TickCount>(1, System::ScaleTicksToOverclock(min_ticks_for_this_timer));
min_ticks = std::min(min_ticks, min_ticks_for_this_timer); min_ticks = std::min(min_ticks, ticks);
}
if (cs.mode.irq_on_overflow)
{
TickCount ticks = static_cast<TickCount>(0xFFFFu - cs.counter);
if (cs.external_counting_enabled) // sysclk/8 for timer 2
ticks *= 8;
min_ticks = std::min(min_ticks, ticks);
}
} }
return min_ticks; return System::ScaleTicksToOverclock(std::max<TickCount>(1, min_ticks));
} }
void Timers::UpdateSysClkEvent() void Timers::UpdateSysClkEvent()
{ {
// Still update once every 100ms. If we get polled we'll execute sooner. m_sysclk_event->Schedule(GetTicksUntilNextInterrupt());
const TickCount ticks = GetTicksUntilNextInterrupt();
if (ticks == std::numeric_limits<TickCount>::max())
m_sysclk_event->Schedule(System::GetMaxSliceTicks());
else
m_sysclk_event->Schedule(ticks);
} }
void Timers::DrawDebugStateWindow() void Timers::DrawDebugStateWindow()