public bool SetMinThreads(int workerThreads, int ioCompletionThreads)
{
if (workerThreads < 0 || ioCompletionThreads < 0)
{
return(false);
}
bool addWorker = false;
bool wakeGateThread = false;
_threadAdjustmentLock.Acquire();
try
{
if (workerThreads > _maxThreads || !ThreadPool.CanSetMinIOCompletionThreads(ioCompletionThreads))
{
return(false);
}
ThreadPool.SetMinIOCompletionThreads(ioCompletionThreads);
if (ForcedMinWorkerThreads != 0)
{
return(true);
}
short newMinThreads = (short)Math.Max(1, Math.Min(workerThreads, MaxPossibleThreadCount));
_minThreads = newMinThreads;
if (_numBlockedThreads > 0)
{
// Blocking adjustment will adjust the goal according to its heuristics
if (_pendingBlockingAdjustment != PendingBlockingAdjustment.Immediately)
{
_pendingBlockingAdjustment = PendingBlockingAdjustment.Immediately;
wakeGateThread = true;
}
}
else if (_separated.counts.NumThreadsGoal < newMinThreads)
{
_separated.counts.InterlockedSetNumThreadsGoal(newMinThreads);
if (_separated.numRequestedWorkers > 0)
{
addWorker = true;
}
}
}
finally
{
_threadAdjustmentLock.Release();
}
if (addWorker)
{
WorkerThread.MaybeAddWorkingWorker(this);
}
else if (wakeGateThread)
{
GateThread.Wake(this);
}
return(true);
}
internal void RequestWorker()
{
// The order of operations here is important. MaybeAddWorkingWorker() and EnsureRunning() use speculative checks to
// do their work and the memory barrier from the interlocked operation is necessary in this case for correctness.
Interlocked.Increment(ref _separated.numRequestedWorkers);
WorkerThread.MaybeAddWorkingWorker(this);
GateThread.EnsureRunning(this);
}
// TODO: CoreCLR: Worker Tracking in CoreCLR? (Config name: ThreadPool_EnableWorkerTracking)
private static void GateThreadStart()
{
AppContext.TryGetSwitch("System.Threading.ThreadPool.DisableStarvationDetection", out bool disableStarvationDetection);
AppContext.TryGetSwitch("System.Threading.ThreadPool.DebugBreakOnWorkerStarvation", out bool debuggerBreakOnWorkStarvation);
while (true)
{
RuntimeThread.Sleep(GateThreadDelayMs);
if (ThreadPoolInstance._numRequestedWorkers > 0)
{
WorkerThread.MaybeAddWorkingWorker();
}
if (!s_requested)
{
continue;
}
s_requested = false;
ThreadPoolInstance._cpuUtilization = s_cpu.CurrentUtilization;
if (!disableStarvationDetection)
{
if (ThreadPoolInstance._numRequestedWorkers > 0 && SufficientDelaySinceLastDequeue())
{
try
{
ThreadPoolInstance._hillClimbingThreadAdjustmentLock.Acquire();
ThreadCounts counts = ThreadCounts.VolatileReadCounts(ref ThreadPoolInstance._separated.counts);
// don't add a thread if we're at max or if we are already in the process of adding threads
while (counts.numExistingThreads < ThreadPoolInstance._maxThreads && counts.numExistingThreads >= counts.numThreadsGoal)
{
if (debuggerBreakOnWorkStarvation)
{
Debug.WriteLine("The CLR ThreadPool detected work starvation!");
Debugger.Break();
}
ThreadCounts newCounts = counts;
newCounts.numThreadsGoal = (short)(newCounts.numExistingThreads + 1);
ThreadCounts oldCounts = ThreadCounts.CompareExchangeCounts(ref ThreadPoolInstance._separated.counts, newCounts, counts);
if (oldCounts == counts)
{
HillClimbing.ThreadPoolHillClimber.ForceChange(newCounts.numThreadsGoal, HillClimbing.StateOrTransition.Starvation);
WorkerThread.MaybeAddWorkingWorker();
break;
}
counts = oldCounts;
}
}
finally
{
ThreadPoolInstance._hillClimbingThreadAdjustmentLock.Release();
}
}
}
}
}
//
// This method must only be called if ShouldAdjustMaxWorkersActive has returned true, *and*
// _hillClimbingThreadAdjustmentLock is held.
//
private void AdjustMaxWorkersActive()
{
_hillClimbingThreadAdjustmentLock.VerifyIsLocked();
int currentTicks = Environment.TickCount;
int totalNumCompletions = (int)_completionCounter.Count;
int numCompletions = totalNumCompletions - _separated.priorCompletionCount;
long startTime = _currentSampleStartTime;
long endTime = Stopwatch.GetTimestamp();
long freq = Stopwatch.Frequency;
double elapsedSeconds = (double)(endTime - startTime) / freq;
if (elapsedSeconds * 1000 >= _threadAdjustmentIntervalMs / 2)
{
ThreadCounts currentCounts = ThreadCounts.VolatileReadCounts(ref _separated.counts);
int newMax;
(newMax, _threadAdjustmentIntervalMs) = HillClimbing.ThreadPoolHillClimber.Update(currentCounts.numThreadsGoal, elapsedSeconds, numCompletions);
while (newMax != currentCounts.numThreadsGoal)
{
ThreadCounts newCounts = currentCounts;
newCounts.numThreadsGoal = (short)newMax;
ThreadCounts oldCounts = ThreadCounts.CompareExchangeCounts(ref _separated.counts, newCounts, currentCounts);
if (oldCounts == currentCounts)
{
//
// If we're increasing the max, inject a thread. If that thread finds work, it will inject
// another thread, etc., until nobody finds work or we reach the new maximum.
//
// If we're reducing the max, whichever threads notice this first will sleep and timeout themselves.
//
if (newMax > oldCounts.numThreadsGoal)
{
WorkerThread.MaybeAddWorkingWorker();
}
break;
}
else
{
if (oldCounts.numThreadsGoal > currentCounts.numThreadsGoal && oldCounts.numThreadsGoal >= newMax)
{
// someone (probably the gate thread) increased the thread count more than
// we are about to do. Don't interfere.
break;
}
currentCounts = oldCounts;
}
}
_separated.priorCompletionCount = totalNumCompletions;
_separated.nextCompletedWorkRequestsTime = currentTicks + _threadAdjustmentIntervalMs;
Volatile.Write(ref _separated.priorCompletedWorkRequestsTime, currentTicks);
_currentSampleStartTime = endTime;
}
}
// TODO: CoreCLR: Worker Tracking in CoreCLR? (Config name: ThreadPool_EnableWorkerTracking)
private static void GateThreadStart()
{
_ = s_cpu.CurrentUtilization; // The first reading is over a time range other than what we are focusing on, so we do not use the read.
AppContext.TryGetSwitch("System.Threading.ThreadPool.DisableStarvationDetection", out bool disableStarvationDetection);
AppContext.TryGetSwitch("System.Threading.ThreadPool.DebugBreakOnWorkerStarvation", out bool debuggerBreakOnWorkStarvation);
while (true)
{
s_runGateThreadEvent.WaitOne();
do
{
Thread.Sleep(GateThreadDelayMs);
ThreadPoolInstance._cpuUtilization = s_cpu.CurrentUtilization;
if (!disableStarvationDetection)
{
if (ThreadPoolInstance._numRequestedWorkers > 0 && SufficientDelaySinceLastDequeue())
{
try
{
ThreadPoolInstance._hillClimbingThreadAdjustmentLock.Acquire();
ThreadCounts counts = ThreadCounts.VolatileReadCounts(ref ThreadPoolInstance._separated.counts);
// don't add a thread if we're at max or if we are already in the process of adding threads
while (counts.numExistingThreads < ThreadPoolInstance._maxThreads && counts.numExistingThreads >= counts.numThreadsGoal)
{
if (debuggerBreakOnWorkStarvation)
{
Debugger.Break();
}
ThreadCounts newCounts = counts;
newCounts.numThreadsGoal = (short)(newCounts.numExistingThreads + 1);
ThreadCounts oldCounts = ThreadCounts.CompareExchangeCounts(ref ThreadPoolInstance._separated.counts, newCounts, counts);
if (oldCounts == counts)
{
HillClimbing.ThreadPoolHillClimber.ForceChange(newCounts.numThreadsGoal, HillClimbing.StateOrTransition.Starvation);
WorkerThread.MaybeAddWorkingWorker();
break;
}
counts = oldCounts;
}
}
finally
{
ThreadPoolInstance._hillClimbingThreadAdjustmentLock.Release();
}
}
}
} while (ThreadPoolInstance._numRequestedWorkers > 0 || Interlocked.Decrement(ref s_runningState) > GetRunningStateForNumRuns(0));
}
}
public bool SetMinThreads(int workerThreads, int ioCompletionThreads)
{
if (workerThreads < 0 || ioCompletionThreads < 0)
{
return(false);
}
_maxMinThreadLock.Acquire();
try
{
if (workerThreads > _maxThreads || !ThreadPool.CanSetMinIOCompletionThreads(ioCompletionThreads))
{
return(false);
}
ThreadPool.SetMinIOCompletionThreads(ioCompletionThreads);
if (s_forcedMinWorkerThreads != 0)
{
return(true);
}
short newMinThreads = (short)Math.Max(1, Math.Min(workerThreads, MaxPossibleThreadCount));
_minThreads = newMinThreads;
ThreadCounts counts = _separated.counts.VolatileRead();
while (counts.NumThreadsGoal < newMinThreads)
{
ThreadCounts newCounts = counts;
newCounts.NumThreadsGoal = newMinThreads;
ThreadCounts oldCounts = _separated.counts.InterlockedCompareExchange(newCounts, counts);
if (oldCounts == counts)
{
if (_separated.numRequestedWorkers > 0)
{
WorkerThread.MaybeAddWorkingWorker(this);
}
break;
}
counts = oldCounts;
}
return(true);
}
finally
{
_maxMinThreadLock.Release();
}
}
public bool SetMinThreads(int minThreads)
{
_maxMinThreadLock.Acquire();
try
{
if (minThreads < 0 || minThreads > _maxThreads)
{
return(false);
}
else
{
short threads = (short)Math.Min(minThreads, MaxPossibleThreadCount);
if (s_forcedMinWorkerThreads == 0)
{
_minThreads = threads;
ThreadCounts counts = ThreadCounts.VolatileReadCounts(ref _separated.counts);
while (counts.numThreadsGoal < _minThreads)
{
ThreadCounts newCounts = counts;
newCounts.numThreadsGoal = _minThreads;
ThreadCounts oldCounts = ThreadCounts.CompareExchangeCounts(ref _separated.counts, newCounts, counts);
if (oldCounts == counts)
{
counts = newCounts;
if (newCounts.numThreadsGoal > oldCounts.numThreadsGoal && _numRequestedWorkers > 0)
{
WorkerThread.MaybeAddWorkingWorker();
}
}
else
{
counts = oldCounts;
}
}
}
return(true);
}
}
finally
{
_maxMinThreadLock.Release();
}
}
private uint PerformBlockingAdjustment(bool previousDelayElapsed)
{
uint nextDelayMs;
bool addWorker;
_threadAdjustmentLock.Acquire();
try
{
nextDelayMs = PerformBlockingAdjustment(previousDelayElapsed, out addWorker);
}
finally
{
_threadAdjustmentLock.Release();
}
if (addWorker)
{
WorkerThread.MaybeAddWorkingWorker(this);
}
return(nextDelayMs);
}
internal void RequestWorker()
{
Interlocked.Increment(ref _numRequestedWorkers);
WorkerThread.MaybeAddWorkingWorker();
GateThread.EnsureRunning();
}
//
// This method must only be called if ShouldAdjustMaxWorkersActive has returned true, *and*
// _hillClimbingThreadAdjustmentLock is held.
//
private void AdjustMaxWorkersActive()
{
LowLevelLock threadAdjustmentLock = _threadAdjustmentLock;
if (!threadAdjustmentLock.TryAcquire())
{
// The lock is held by someone else, they will take care of this for us
return;
}
bool addWorker = false;
try
{
// Repeated checks from ShouldAdjustMaxWorkersActive() inside the lock
ThreadCounts counts = _separated.counts;
if (counts.NumProcessingWork > counts.NumThreadsGoal ||
_pendingBlockingAdjustment != PendingBlockingAdjustment.None)
{
return;
}
long endTime = Stopwatch.GetTimestamp();
double elapsedSeconds = Stopwatch.GetElapsedTime(_currentSampleStartTime, endTime).TotalSeconds;
if (elapsedSeconds * 1000 >= _threadAdjustmentIntervalMs / 2)
{
int currentTicks = Environment.TickCount;
int totalNumCompletions = (int)_completionCounter.Count;
int numCompletions = totalNumCompletions - _separated.priorCompletionCount;
short oldNumThreadsGoal = counts.NumThreadsGoal;
int newNumThreadsGoal;
(newNumThreadsGoal, _threadAdjustmentIntervalMs) =
HillClimbing.ThreadPoolHillClimber.Update(oldNumThreadsGoal, elapsedSeconds, numCompletions);
if (oldNumThreadsGoal != (short)newNumThreadsGoal)
{
_separated.counts.InterlockedSetNumThreadsGoal((short)newNumThreadsGoal);
//
// If we're increasing the goal, inject a thread. If that thread finds work, it will inject
// another thread, etc., until nobody finds work or we reach the new goal.
//
// If we're reducing the goal, whichever threads notice this first will sleep and timeout themselves.
//
if (newNumThreadsGoal > oldNumThreadsGoal)
{
addWorker = true;
}
}
_separated.priorCompletionCount = totalNumCompletions;
_separated.nextCompletedWorkRequestsTime = currentTicks + _threadAdjustmentIntervalMs;
Volatile.Write(ref _separated.priorCompletedWorkRequestsTime, currentTicks);
_currentSampleStartTime = endTime;
}
}
finally
{
threadAdjustmentLock.Release();
}
if (addWorker)
{
WorkerThread.MaybeAddWorkingWorker(this);
}
}
public bool SetMinThreads(int workerThreads, int ioCompletionThreads)
{
if (workerThreads < 0 || ioCompletionThreads < 0)
{
return(false);
}
bool addWorker = false;
bool wakeGateThread = false;
_threadAdjustmentLock.Acquire();
try
{
if (workerThreads > _maxThreads)
{
return(false);
}
if (ThreadPool.UsePortableThreadPoolForIO
? ioCompletionThreads > _legacy_maxIOCompletionThreads
: !ThreadPool.CanSetMinIOCompletionThreads(ioCompletionThreads))
{
return(false);
}
if (HasForcedMinThreads && workerThreads != ForcedMinWorkerThreads)
{
return(false);
}
if (ThreadPool.UsePortableThreadPoolForIO)
{
_legacy_minIOCompletionThreads = (short)Math.Max(1, ioCompletionThreads);
}
else
{
ThreadPool.SetMinIOCompletionThreads(ioCompletionThreads);
}
short newMinThreads = (short)Math.Max(1, workerThreads);
if (newMinThreads == _minThreads)
{
return(true);
}
_minThreads = newMinThreads;
if (_numBlockedThreads > 0)
{
// Blocking adjustment will adjust the goal according to its heuristics
if (_pendingBlockingAdjustment != PendingBlockingAdjustment.Immediately)
{
_pendingBlockingAdjustment = PendingBlockingAdjustment.Immediately;
wakeGateThread = true;
}
}
else if (_separated.counts.NumThreadsGoal < newMinThreads)
{
_separated.counts.InterlockedSetNumThreadsGoal(newMinThreads);
if (_separated.numRequestedWorkers > 0)
{
addWorker = true;
}
}
if (NativeRuntimeEventSource.Log.IsEnabled())
{
NativeRuntimeEventSource.Log.ThreadPoolMinMaxThreads(
(ushort)_minThreads,
(ushort)_maxThreads,
(ushort)_legacy_minIOCompletionThreads,
(ushort)_legacy_maxIOCompletionThreads);
}
}
finally
{
_threadAdjustmentLock.Release();
}
if (addWorker)
{
WorkerThread.MaybeAddWorkingWorker(this);
}
else if (wakeGateThread)
{
GateThread.Wake(this);
}
return(true);
}
private static void GateThreadStart()
{
bool disableStarvationDetection =
AppContextConfigHelper.GetBooleanConfig("System.Threading.ThreadPool.DisableStarvationDetection", false);
bool debuggerBreakOnWorkStarvation =
AppContextConfigHelper.GetBooleanConfig("System.Threading.ThreadPool.DebugBreakOnWorkerStarvation", false);
// The first reading is over a time range other than what we are focusing on, so we do not use the read other
// than to send it to any runtime-specific implementation that may also use the CPU utilization.
CpuUtilizationReader cpuUtilizationReader = default;
_ = cpuUtilizationReader.CurrentUtilization;
PortableThreadPool threadPoolInstance = ThreadPoolInstance;
LowLevelLock hillClimbingThreadAdjustmentLock = threadPoolInstance._hillClimbingThreadAdjustmentLock;
while (true)
{
s_runGateThreadEvent.WaitOne();
bool needGateThreadForRuntime;
do
{
Thread.Sleep(GateThreadDelayMs);
if (ThreadPool.EnableWorkerTracking && PortableThreadPoolEventSource.Log.IsEnabled())
{
PortableThreadPoolEventSource.Log.ThreadPoolWorkingThreadCount(
(uint)threadPoolInstance.GetAndResetHighWatermarkCountOfThreadsProcessingUserCallbacks());
}
int cpuUtilization = cpuUtilizationReader.CurrentUtilization;
threadPoolInstance._cpuUtilization = cpuUtilization;
needGateThreadForRuntime = ThreadPool.PerformRuntimeSpecificGateActivities(cpuUtilization);
if (!disableStarvationDetection &&
threadPoolInstance._separated.numRequestedWorkers > 0 &&
SufficientDelaySinceLastDequeue(threadPoolInstance))
{
try
{
hillClimbingThreadAdjustmentLock.Acquire();
ThreadCounts counts = threadPoolInstance._separated.counts.VolatileRead();
// Don't add a thread if we're at max or if we are already in the process of adding threads.
// This logic is slightly different from the native implementation in CoreCLR because there are
// no retired threads. In the native implementation, when hill climbing reduces the thread count
// goal, threads that are stopped from processing work are switched to "retired" state, and they
// don't count towards the equivalent existing thread count. In this implementation, the
// existing thread count includes any worker thread that has not yet exited, including those
// stopped from working by hill climbing, so here the number of threads processing work, instead
// of the number of existing threads, is compared with the goal. There may be alternative
// solutions, for now this is only to maintain consistency in behavior.
while (
counts.NumExistingThreads < threadPoolInstance._maxThreads &&
counts.NumProcessingWork >= counts.NumThreadsGoal)
{
if (debuggerBreakOnWorkStarvation)
{
Debugger.Break();
}
ThreadCounts newCounts = counts;
short newNumThreadsGoal = (short)(counts.NumProcessingWork + 1);
newCounts.NumThreadsGoal = newNumThreadsGoal;
ThreadCounts oldCounts = threadPoolInstance._separated.counts.InterlockedCompareExchange(newCounts, counts);
if (oldCounts == counts)
{
HillClimbing.ThreadPoolHillClimber.ForceChange(newNumThreadsGoal, HillClimbing.StateOrTransition.Starvation);
WorkerThread.MaybeAddWorkingWorker(threadPoolInstance);
break;
}
counts = oldCounts;
}
}
finally
{
hillClimbingThreadAdjustmentLock.Release();
}
}
} while (
needGateThreadForRuntime ||
threadPoolInstance._separated.numRequestedWorkers > 0 ||
Interlocked.Decrement(ref threadPoolInstance._separated.gateThreadRunningState) > GetRunningStateForNumRuns(0));
}
}
//
// This method must only be called if ShouldAdjustMaxWorkersActive has returned true, *and*
// _hillClimbingThreadAdjustmentLock is held.
//
private void AdjustMaxWorkersActive()
{
LowLevelLock threadAdjustmentLock = _threadAdjustmentLock;
if (!threadAdjustmentLock.TryAcquire())
{
// The lock is held by someone else, they will take care of this for us
return;
}
bool addWorker = false;
try
{
// Skip hill climbing when there is a pending blocking adjustment. Hill climbing may otherwise bypass the
// blocking adjustment heuristics and increase the thread count too quickly.
if (_pendingBlockingAdjustment != PendingBlockingAdjustment.None)
{
return;
}
long startTime = _currentSampleStartTime;
long endTime = Stopwatch.GetTimestamp();
long freq = Stopwatch.Frequency;
double elapsedSeconds = (double)(endTime - startTime) / freq;
if (elapsedSeconds * 1000 >= _threadAdjustmentIntervalMs / 2)
{
int currentTicks = Environment.TickCount;
int totalNumCompletions = (int)_completionCounter.Count;
int numCompletions = totalNumCompletions - _separated.priorCompletionCount;
int newNumThreadsGoal;
(newNumThreadsGoal, _threadAdjustmentIntervalMs) =
HillClimbing.ThreadPoolHillClimber.Update(_separated.numThreadsGoal, elapsedSeconds, numCompletions);
short oldNumThreadsGoal = _separated.numThreadsGoal;
if (oldNumThreadsGoal != (short)newNumThreadsGoal)
{
_separated.numThreadsGoal = (short)newNumThreadsGoal;
//
// If we're increasing the goal, inject a thread. If that thread finds work, it will inject
// another thread, etc., until nobody finds work or we reach the new goal.
//
// If we're reducing the goal, whichever threads notice this first will sleep and timeout themselves.
//
if (newNumThreadsGoal > oldNumThreadsGoal)
{
addWorker = true;
}
}
_separated.priorCompletionCount = totalNumCompletions;
_separated.nextCompletedWorkRequestsTime = currentTicks + _threadAdjustmentIntervalMs;
Volatile.Write(ref _separated.priorCompletedWorkRequestsTime, currentTicks);
_currentSampleStartTime = endTime;
}
}
finally
{
threadAdjustmentLock.Release();
}
if (addWorker)
{
WorkerThread.MaybeAddWorkingWorker(this);
}
}
private static void GateThreadStart()
{
bool disableStarvationDetection =
AppContextConfigHelper.GetBooleanConfig("System.Threading.ThreadPool.DisableStarvationDetection", false);
bool debuggerBreakOnWorkStarvation =
AppContextConfigHelper.GetBooleanConfig("System.Threading.ThreadPool.DebugBreakOnWorkerStarvation", false);
// The first reading is over a time range other than what we are focusing on, so we do not use the read other
// than to send it to any runtime-specific implementation that may also use the CPU utilization.
CpuUtilizationReader cpuUtilizationReader = default;
_ = cpuUtilizationReader.CurrentUtilization;
PortableThreadPool threadPoolInstance = ThreadPoolInstance;
LowLevelLock threadAdjustmentLock = threadPoolInstance._threadAdjustmentLock;
DelayHelper delayHelper = default;
if (BlockingConfig.IsCooperativeBlockingEnabled)
{
// Initialize memory usage and limits, and register to update them on gen 2 GCs
threadPoolInstance.OnGen2GCCallback();
Gen2GcCallback.Register(threadPoolInstance.OnGen2GCCallback);
}
while (true)
{
RunGateThreadEvent.WaitOne();
int currentTimeMs = Environment.TickCount;
delayHelper.SetGateActivitiesTime(currentTimeMs);
while (true)
{
bool wasSignaledToWake = DelayEvent.WaitOne((int)delayHelper.GetNextDelay(currentTimeMs));
currentTimeMs = Environment.TickCount;
// Thread count adjustment for cooperative blocking
do
{
PendingBlockingAdjustment pendingBlockingAdjustment = threadPoolInstance._pendingBlockingAdjustment;
if (pendingBlockingAdjustment == PendingBlockingAdjustment.None)
{
delayHelper.ClearBlockingAdjustmentDelay();
break;
}
bool previousDelayElapsed = false;
if (delayHelper.HasBlockingAdjustmentDelay)
{
previousDelayElapsed =
delayHelper.HasBlockingAdjustmentDelayElapsed(currentTimeMs, wasSignaledToWake);
if (pendingBlockingAdjustment == PendingBlockingAdjustment.WithDelayIfNecessary &&
!previousDelayElapsed)
{
break;
}
}
uint nextDelayMs = threadPoolInstance.PerformBlockingAdjustment(previousDelayElapsed);
if (nextDelayMs <= 0)
{
delayHelper.ClearBlockingAdjustmentDelay();
}
else
{
delayHelper.SetBlockingAdjustmentTimeAndDelay(currentTimeMs, nextDelayMs);
}
} while (false);
//
// Periodic gate activities
//
if (!delayHelper.ShouldPerformGateActivities(currentTimeMs, wasSignaledToWake))
{
continue;
}
if (ThreadPool.EnableWorkerTracking && NativeRuntimeEventSource.Log.IsEnabled())
{
NativeRuntimeEventSource.Log.ThreadPoolWorkingThreadCount(
(uint)threadPoolInstance.GetAndResetHighWatermarkCountOfThreadsProcessingUserCallbacks());
}
int cpuUtilization = cpuUtilizationReader.CurrentUtilization;
threadPoolInstance._cpuUtilization = cpuUtilization;
bool needGateThreadForRuntime = ThreadPool.PerformRuntimeSpecificGateActivities(cpuUtilization);
if (!disableStarvationDetection &&
threadPoolInstance._pendingBlockingAdjustment == PendingBlockingAdjustment.None &&
threadPoolInstance._separated.numRequestedWorkers > 0 &&
SufficientDelaySinceLastDequeue(threadPoolInstance))
{
bool addWorker = false;
threadAdjustmentLock.Acquire();
try
{
// Don't add a thread if we're at max or if we are already in the process of adding threads.
// This logic is slightly different from the native implementation in CoreCLR because there are
// no retired threads. In the native implementation, when hill climbing reduces the thread count
// goal, threads that are stopped from processing work are switched to "retired" state, and they
// don't count towards the equivalent existing thread count. In this implementation, the
// existing thread count includes any worker thread that has not yet exited, including those
// stopped from working by hill climbing, so here the number of threads processing work, instead
// of the number of existing threads, is compared with the goal. There may be alternative
// solutions, for now this is only to maintain consistency in behavior.
ThreadCounts counts = threadPoolInstance._separated.counts;
if (counts.NumProcessingWork < threadPoolInstance._maxThreads &&
counts.NumProcessingWork >= threadPoolInstance._separated.numThreadsGoal)
{
if (debuggerBreakOnWorkStarvation)
{
Debugger.Break();
}
short newNumThreadsGoal = (short)(counts.NumProcessingWork + 1);
threadPoolInstance._separated.numThreadsGoal = newNumThreadsGoal;
HillClimbing.ThreadPoolHillClimber.ForceChange(
newNumThreadsGoal,
HillClimbing.StateOrTransition.Starvation);
addWorker = true;
}
}
finally
{
threadAdjustmentLock.Release();
}
if (addWorker)
{
WorkerThread.MaybeAddWorkingWorker(threadPoolInstance);
}
}
if (!needGateThreadForRuntime &&
threadPoolInstance._separated.numRequestedWorkers <= 0 &&
threadPoolInstance._pendingBlockingAdjustment == PendingBlockingAdjustment.None &&
Interlocked.Decrement(ref threadPoolInstance._separated.gateThreadRunningState) <= GetRunningStateForNumRuns(0))
{
break;
}
}
}
}