private int CreatePerfCounterProxies(string processInstanceName)
{
var perfCounterProxies = new Dictionary <GCSampleType, IPerformanceCounterProxy>();
var failedSampleTypes = new List <GCSampleType>();
foreach (var sampleTypeEnum in _perfCounterNames.Keys)
{
try
{
perfCounterProxies[sampleTypeEnum] = _pcProxyFactory.CreatePerformanceCounterProxy(GCPerfCounterCategoryName, _perfCounterNames[sampleTypeEnum], processInstanceName);
}
catch (UnauthorizedAccessException)
{
throw; //Let the caller receive this so that they may shutdown the sampler.
}
catch (Exception ex)
{
failedSampleTypes.Add(sampleTypeEnum);
LogMessage(LogLevel.Debug, $"Error encountered during the creation of performance counter for '{sampleTypeEnum}' for Performance Counter Instance '{processInstanceName}'. Metrics of this type will not be captured. Error : {ex}");
}
}
//Print message indicating which perf counter proxies failed to start.
if (failedSampleTypes.Count > 0)
{
var msgToken = string.Join(", ", failedSampleTypes.Select(x => x.ToString()).ToArray());
LogMessage(LogLevel.Warn, $"The following Performance Counters for Performance Counter Instance '{processInstanceName}' could not be started: {msgToken}. Debug Level logs will contain more information.");
}
var oldProxies = Interlocked.Exchange(ref _perfCounterProxies, perfCounterProxies);
if (_perfCounterProxies.Count > 0)
{
LogMessage(LogLevel.Debug, $"Sampler is collecting {_perfCounterProxies.Count} performance counter(s) for Performance Counter Instance '{processInstanceName}'.");
}
if (oldProxies != null && oldProxies.Count > 0)
{
DisposeProxies(oldProxies.Values);
}
return(_perfCounterProxies.Count);
}
public void SamplerCalculatesValuesCorrectly()
{
const int expectedSampleCount = 2;
const float startVal = 3f;
const float deltaVal = 10f;
var lastPerfCounterValue = 0f;
var testPerfCounterValue = startVal;
//Create a mock proxy that allows us to return a specific value and ensure that the proxy factory returns this proxy.
var mockProxy = Mock.Create <IPerformanceCounterProxy>();
Mock.Arrange(() => mockProxy.NextValue())
.Returns(() => { return(testPerfCounterValue); });
Mock.Arrange(() => _perfCounterProxyFactory.CreatePerformanceCounterProxy(Arg.IsAny <string>(), Arg.IsAny <string>(), Arg.IsAny <string>()))
.Returns(mockProxy);
Mock.Arrange(() => _perfCounterProxyFactory.GetCurrentProcessInstanceNameForCategory(Arg.IsAny <string>(), Arg.IsAny <string>()))
.Returns("Test Value");
//Holds the results of the perf counter captures so that we may compare them as part of our assertions.
List <Dictionary <GCSampleType, float> > perfCounterValues = new List <Dictionary <GCSampleType, float> >();
//Intercept the transform method so that we can collect the values that were sampled from the performance counters
var gcSampleTransformer = Mock.Create <IGcSampleTransformer>();
Mock.Arrange(() => gcSampleTransformer.Transform(Arg.IsAny <Dictionary <GCSampleType, float> >()))
.DoInstead <Dictionary <GCSampleType, float> >((sampleValues) =>
{
lastPerfCounterValue = testPerfCounterValue;
perfCounterValues.Add(sampleValues);
testPerfCounterValue += deltaVal;
});
var sampler = new GcSampler(_scheduler, gcSampleTransformer, _perfCounterProxyFactory);
//Act
sampler.Start();
_sampleAction(); //Collect Sample 1
_sampleAction(); //Collect Sample 2
//Assert
NrAssert.Multiple(
() => Assert.AreEqual(expectedSampleCount, perfCounterValues.Count, $"There should have been {expectedSampleCount} samples collected"),
() => Assert.AreEqual(_countSampleTypes, perfCounterValues[0].Count, $"There should be {_countSampleTypes} in the first sample"),
() => Assert.AreEqual(_countSampleTypes, perfCounterValues[1].Count, $"There should be {_countSampleTypes} in the second sample")
);
//Validate the sampled(calculated) value for each counter type.
foreach (var gcSampleType in perfCounterValues[0].Keys)
{
//For the first sample, all should have the same value
Assert.AreEqual(startVal, perfCounterValues[0][gcSampleType]);
//For the second sample...
switch (gcSampleType)
{
//...delta values should represent the size of the delta
case GCSampleType.Gen0CollectionCount:
case GCSampleType.Gen1CollectionCount:
case GCSampleType.Gen2CollectionCount:
case GCSampleType.InducedCount:
Assert.AreEqual(deltaVal, perfCounterValues[1][gcSampleType]);
break;
//...other measurements should be passed through with the perf counter value
default:
Assert.AreEqual(lastPerfCounterValue, perfCounterValues[1][gcSampleType]);
break;
}
}
}