Merge pull request #2408 from Subv/priority_boosting

Kernel: Removed the priority boost code for starved threads.
This commit is contained in:
bunnei 2017-01-06 00:40:39 -05:00 committed by GitHub
commit 1c792389e6

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@ -141,28 +141,6 @@ void ArbitrateAllThreads(u32 address) {
}
}
/// Boost low priority threads (temporarily) that have been starved
static void PriorityBoostStarvedThreads() {
u64 current_ticks = CoreTiming::GetTicks();
for (auto& thread : thread_list) {
// TODO(bunnei): Threads that have been waiting to be scheduled for `boost_ticks` (or
// longer) will have their priority temporarily adjusted to 1 higher than the highest
// priority thread to prevent thread starvation. This general behavior has been verified
// on hardware. However, this is almost certainly not perfect, and the real CTR OS scheduler
// should probably be reversed to verify this.
const u64 boost_timeout = 2000000; // Boost threads that have been ready for > this long
u64 delta = current_ticks - thread->last_running_ticks;
if (thread->status == THREADSTATUS_READY && delta > boost_timeout) {
const s32 priority = std::max(ready_queue.get_first()->current_priority - 1, 0);
thread->BoostPriority(priority);
}
}
}
/**
* Switches the CPU's active thread context to that of the specified thread
* @param new_thread The thread to switch to
@ -196,9 +174,6 @@ static void SwitchContext(Thread* new_thread) {
ready_queue.remove(new_thread->current_priority, new_thread);
new_thread->status = THREADSTATUS_RUNNING;
// Restores thread to its nominal priority if it has been temporarily changed
new_thread->current_priority = new_thread->nominal_priority;
Core::CPU().LoadContext(new_thread->context);
Core::CPU().SetCP15Register(CP15_THREAD_URO, new_thread->GetTLSAddress());
} else {
@ -534,8 +509,6 @@ SharedPtr<Thread> SetupMainThread(u32 entry_point, s32 priority) {
}
void Reschedule() {
PriorityBoostStarvedThreads();
Thread* cur = GetCurrentThread();
Thread* next = PopNextReadyThread();