public bool Start(uint frequencyInMsec, uint durationInMsec, ISampleSink sampleSink, INativeMethods nativeMethods)
{
_shutdownEvent.Reset();
//atomic compare and set - if _workerRunning was a zero, it's now a 1 and create worker will be true
bool createWorker = 0 == Interlocked.CompareExchange(ref _workerRunning, 1, 0);
if (createWorker)
{
_samplingWorker = new Thread(() => InternalPolling_WaitCallback(frequencyInMsec, durationInMsec, sampleSink, nativeMethods))
{
IsBackground = true
};
_samplingWorker.Start();
}
//return whether or not we created a session
return(createWorker);
}
/// <summary>
/// Polls for profiled threads.
/// </summary>
private void InternalPolling_WaitCallback(uint frequencyInMsec, uint durationInMsec, ISampleSink sampleSink, INativeMethods nativeMethods)
{
int samples = 0;
var lastTickOfSamplingPeriod = DateTime.UtcNow.AddMilliseconds(durationInMsec).Ticks;
try
{
while (!_shutdownEvent.Wait((int)frequencyInMsec))
{
if (DateTime.UtcNow.Ticks > lastTickOfSamplingPeriod)
{
_shutdownEvent.Set();
Log.Debug("InternalPolling_WaitCallback: Duration Elapsed -- Stopping Sampler");
break;
}
try
{
var threadSnapshots = GetProfileWithRelease(out int result);
if (result >= 0)
{
++samples;
sampleSink.SampleAcquired(threadSnapshots);
}
else
{
Log.Error($"Thread Profile sampling failed. ({result:X})");
}
}
catch (Exception ex)
{
Log.Error(ex);
}
}
}
catch (Exception ex)
{
Log.Error(ex);
}
finally
{
Log.Info($"samples ({samples})");
sampleSink.SamplingComplete();
nativeMethods.ShutdownNativeThreadProfiler();
_workerRunning = 0;
}
}
