private int _logSize; // SOS's ThreadPool command depends on this name
public HillClimbing()
{
_wavePeriod = AppContextConfigHelper.GetInt32Config("System.Threading.ThreadPool.HillClimbing.WavePeriod", 4, false);
_maxThreadWaveMagnitude = AppContextConfigHelper.GetInt32Config("System.Threading.ThreadPool.HillClimbing.MaxWaveMagnitude", 20, false);
_threadMagnitudeMultiplier = AppContextConfigHelper.GetInt32Config("System.Threading.ThreadPool.HillClimbing.WaveMagnitudeMultiplier", 100, false) / 100.0;
_samplesToMeasure = _wavePeriod * AppContextConfigHelper.GetInt32Config("System.Threading.ThreadPool.HillClimbing.WaveHistorySize", 8, false);
_targetThroughputRatio = AppContextConfigHelper.GetInt32Config("System.Threading.ThreadPool.HillClimbing.Bias", 15, false) / 100.0;
_targetSignalToNoiseRatio = AppContextConfigHelper.GetInt32Config("System.Threading.ThreadPool.HillClimbing.TargetSignalToNoiseRatio", 300, false) / 100.0;
_maxChangePerSecond = AppContextConfigHelper.GetInt32Config("System.Threading.ThreadPool.HillClimbing.MaxChangePerSecond", 4, false);
_maxChangePerSample = AppContextConfigHelper.GetInt32Config("System.Threading.ThreadPool.HillClimbing.MaxChangePerSample", 20, false);
int sampleIntervalMsLow = AppContextConfigHelper.GetInt32Config("System.Threading.ThreadPool.HillClimbing.SampleIntervalLow", DefaultSampleIntervalMsLow, false);
int sampleIntervalMsHigh = AppContextConfigHelper.GetInt32Config("System.Threading.ThreadPool.HillClimbing.SampleIntervalHigh", DefaultSampleIntervalMsHigh, false);
if (sampleIntervalMsLow <= sampleIntervalMsHigh)
{
_sampleIntervalMsLow = sampleIntervalMsLow;
_sampleIntervalMsHigh = sampleIntervalMsHigh;
}
else
{
_sampleIntervalMsLow = DefaultSampleIntervalMsLow;
_sampleIntervalMsHigh = DefaultSampleIntervalMsHigh;
}
_throughputErrorSmoothingFactor = AppContextConfigHelper.GetInt32Config("System.Threading.ThreadPool.HillClimbing.ErrorSmoothingFactor", 1, false) / 100.0;
_gainExponent = AppContextConfigHelper.GetInt32Config("System.Threading.ThreadPool.HillClimbing.GainExponent", 200, false) / 100.0;
_maxSampleError = AppContextConfigHelper.GetInt32Config("System.Threading.ThreadPool.HillClimbing.MaxSampleErrorPercent", 15, false) / 100.0;
_samples = new double[_samplesToMeasure];
_threadCounts = new double[_samplesToMeasure];
_currentSampleMs = _randomIntervalGenerator.Next(_sampleIntervalMsLow, _sampleIntervalMsHigh + 1);
}
private static HillClimbing CreateHillClimber()
{
// Default values pulled from CoreCLR
return(new HillClimbing(wavePeriod: AppContextConfigHelper.GetInt32Config("HillClimbing_WavePeriod", 4, false),
maxWaveMagnitude: AppContextConfigHelper.GetInt32Config("HillClimbing_MaxWaveMagnitude", 20, false),
waveMagnitudeMultiplier: AppContextConfigHelper.GetInt32Config("HillClimbing_WaveMagnitudeMultiplier", 100, false) / 100.0,
waveHistorySize: AppContextConfigHelper.GetInt32Config("HillClimbing_WaveHistorySize", 8, false),
targetThroughputRatio: AppContextConfigHelper.GetInt32Config("HillClimbing_Bias", 15, false) / 100.0,
targetSignalToNoiseRatio: AppContextConfigHelper.GetInt32Config("HillClimbing_TargetSignalToNoiseRatio", 300, false) / 100.0,
maxChangePerSecond: AppContextConfigHelper.GetInt32Config("HillClimbing_MaxChangePerSecond", 4, false),
maxChangePerSample: AppContextConfigHelper.GetInt32Config("HillClimbing_MaxChangePerSample", 20, false),
sampleIntervalMsLow: AppContextConfigHelper.GetInt32Config("HillClimbing_SampleIntervalLow", DefaultSampleIntervalMsLow, false),
sampleIntervalMsHigh: AppContextConfigHelper.GetInt32Config("HillClimbing_SampleIntervalHigh", DefaultSampleIntervalMsHigh, false),
errorSmoothingFactor: AppContextConfigHelper.GetInt32Config("HillClimbing_ErrorSmoothingFactor", 1, false) / 100.0,
gainExponent: AppContextConfigHelper.GetInt32Config("HillClimbing_GainExponent", 200, false) / 100.0,
maxSampleError: AppContextConfigHelper.GetInt32Config("HillClimbing_MaxSampleErrorPercent", 15, false) / 100.0
));
}
private static int GetIOCompletionPollerCount()
{
// Named for consistency with SocketAsyncEngine.Unix.cs, this environment variable is checked to override the exact
// number of IO completion poller threads to use. See the comment in SocketAsyncEngine.Unix.cs about its potential
// uses. For this implementation, the ProcessorsPerIOPollerThread config option below may be preferable as it may be
// less machine-specific.
if (uint.TryParse(Environment.GetEnvironmentVariable("DOTNET_SYSTEM_NET_SOCKETS_THREAD_COUNT"), out uint count))
{
return(Math.Min((int)count, MaxPossibleThreadCount));
}
if (UnsafeInlineIOCompletionCallbacks)
{
// In this mode, default to ProcessorCount pollers to ensure that all processors can be utilized if more work
// happens on the poller threads
return(Environment.ProcessorCount);
}
int processorsPerPoller =
AppContextConfigHelper.GetInt32Config("System.Threading.ThreadPool.ProcessorsPerIOPollerThread", 12, false);
return((Environment.ProcessorCount - 1) / processorsPerPoller + 1);
}
#pragma warning disable CA1810 // remove the explicit static constructor
static BlockingConfig()
{
// Summary description of how blocking compensation works and how the config settings below are used:
// - After the thread count based on MinThreads is reached, up to ThreadsToAddWithoutDelay additional threads
// may be created without a delay
// - After that, before each additional thread is created, a delay is induced, starting with DelayStepMs
// - For every ThreadsPerDelayStep threads that are added with a delay, an additional DelayStepMs is added to
// the delay
// - The delay may not exceed MaxDelayMs
// - Delays are only induced before creating threads. If threads are already available, they would be released
// without delay to compensate for cooperative blocking.
// - Physical memory usage and limits are also used and beyond a threshold, the system switches to fallback mode
// where threads would be created if starvation is detected, typically with higher delays
// After the thread count based on MinThreads is reached, this value (after it is multiplied by the processor
// count) specifies how many additional threads may be created without a delay
int blocking_threadsToAddWithoutDelay_procCountFactor =
AppContextConfigHelper.GetInt32Config(
"System.Threading.ThreadPool.Blocking.ThreadsToAddWithoutDelay_ProcCountFactor",
1,
false);
// After the thread count based on ThreadsToAddWithoutDelay is reached, this value (after it is multiplied by
// the processor count) specifies after how many threads an additional DelayStepMs would be added to the delay
// before each new thread is created
int blocking_threadsPerDelayStep_procCountFactor =
AppContextConfigHelper.GetInt32Config(
"System.Threading.ThreadPool.Blocking.ThreadsPerDelayStep_ProcCountFactor",
1,
false);
// After the thread count based on ThreadsToAddWithoutDelay is reached, this value specifies how much additional
// delay to add per ThreadsPerDelayStep threads, which would be applied before each new thread is created
DelayStepMs =
(uint)AppContextConfigHelper.GetInt32Config(
"System.Threading.ThreadPool.Blocking.DelayStepMs",
25,
false);
// After the thread count based on ThreadsToAddWithoutDelay is reached, this value specifies the max delay to
// use before each new thread is created
MaxDelayMs =
(uint)AppContextConfigHelper.GetInt32Config(
"System.Threading.ThreadPool.Blocking.MaxDelayMs",
250,
false);
int processorCount = Environment.ProcessorCount;
ThreadsToAddWithoutDelay = (short)(processorCount * blocking_threadsToAddWithoutDelay_procCountFactor);
if (ThreadsToAddWithoutDelay > MaxPossibleThreadCount ||
ThreadsToAddWithoutDelay / processorCount != blocking_threadsToAddWithoutDelay_procCountFactor)
{
ThreadsToAddWithoutDelay = MaxPossibleThreadCount;
}
blocking_threadsPerDelayStep_procCountFactor = Math.Max(1, blocking_threadsPerDelayStep_procCountFactor);
short maxThreadsPerDelayStep = (short)(MaxPossibleThreadCount - ThreadsToAddWithoutDelay);
ThreadsPerDelayStep =
(short)(processorCount * blocking_threadsPerDelayStep_procCountFactor);
if (ThreadsPerDelayStep > maxThreadsPerDelayStep ||
ThreadsPerDelayStep / processorCount != blocking_threadsPerDelayStep_procCountFactor)
{
ThreadsPerDelayStep = maxThreadsPerDelayStep;
}
MaxDelayMs = Math.Max(1, Math.Min(MaxDelayMs, GateThread.GateActivitiesPeriodMs));
DelayStepMs = Math.Max(1, Math.Min(DelayStepMs, MaxDelayMs));
}
