AuroraSupport/AuroraRuntime
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[*] Improve NT semaphore: use a different internal api now. Might help uncontested servers with work queues using semaphores

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This commit is contained in:
Reece Wilson 2023-09-12 13:28:46 +01:00
parent ffd61d4d54
commit 403c186f0a
1 changed files with 12 additions and 11 deletions
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23
Source/Threading/Primitives/AuSemaphore.NT.cpp
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@ -102,11 +102,12 @@ namespace Aurora::Threading::Primitives
if (gUseNativeWaitSemapahore)
{
auto pCounter = this->GetSleepCounter();
while (!this->TryLockNoSpin())
{
static const AuUInt32 kExpect { 0 };
auto pCounter = this->GetSleepCounter();
AuAtomicAdd(pCounter, 1u);
bool bStatus = InternalLTSWaitOnAddressHighRes(&this->dwState_, &kExpect, sizeof(kExpect), uEnd);
AuAtomicSub(pCounter, 1u);
@ -158,12 +159,12 @@ namespace Aurora::Threading::Primitives
if (gUseNativeWaitSemapahore)
{
AuUInt32 uYieldCounter {};
auto pCounter = this->GetSleepCounter();
while (!this->TryLockNoSpin())
{
static const AuUInt32 kExpect { 0 };
auto pCounter = this->GetSleepCounter();
AuAtomicAdd(pCounter, 1u);
bool bStatus = InternalLTSWaitOnAddressHighRes(&this->dwState_, &kExpect, sizeof(kExpect), qwTimeoutAbs);
AuAtomicSub(pCounter, 1u);
@ -211,21 +212,21 @@ namespace Aurora::Threading::Primitives
SysAssert(status, "Couldn't lock semaphore");
}
void SemaphoreImpl::Unlock(AuUInt16 count)
void SemaphoreImpl::Unlock(AuUInt16 uCount)
{
if (gUseNativeWaitSemapahore)
{
AuAtomicAdd<AuUInt32>(&this->dwState_, count);
AuAtomicAdd<AuUInt32>(&this->dwState_, uCount);
if (AuAtomicLoad(this->GetSleepCounter()))
if (auto dwSleeping = AuAtomicLoad(this->GetSleepCounter()))
{
if (count == 1)
if (uCount == 1)
{
InternalLTSWakeOne((void *)&this->dwState_);
}
else
{
InternalLTSWakeAll((void *)&this->dwState_);
InternalLTSWakeCount((void *)&this->dwState_, AuMin<AuUInt32>(uCount, dwSleeping));
}
}
}
@ -236,16 +237,16 @@ namespace Aurora::Threading::Primitives
// we cant efficiently access the conditions state or atomic guarantees...
this->mutex.Lock(); // do not [re]move this lock fence
AuAtomicAdd<AuUInt32>(&this->dwState_, count); // this could be moved anywhere above the unlock, including above the lock.
AuAtomicAdd<AuUInt32>(&this->dwState_, uCount); // this could be moved anywhere above the unlock, including above the lock.
this->mutex.Unlock();
if (count == 1)
if (uCount == 1)
{
this->var.Signal();
}
else
{
if (count >= 3) // ...this is the only optimization we can hope to achieve
if (uCount >= 3) // ...this is the only optimization we can hope to achieve
{
// we can always save a few cycles by doing an atomic broadcast on a contended semaphore
// waking up the wrong amount of threads probably doesn't matter at this point, on these target platforms
@ -254,7 +255,7 @@ namespace Aurora::Threading::Primitives
else // ...otherwise, do the handshake just a few times
{
// doing the condvar handshake for the exact amount of threads you need, once the cond is contended, can pay off
for (AU_ITERATE_N(i, count))
for (AU_ITERATE_N(i, uCount))
{
(void)i;
this->var.Signal();