/// <summary>
/// Get an interval histogram, which will include a stable, consistent view of all value counts
/// accumulated since the last interval histogram was taken.
/// {@link Recorder#GetIntervalHistogram(Histogram histogramToRecycle)
/// GetIntervalHistogram(histogramToRecycle)}
/// accepts a previously returned interval histogram that can be recycled internally to avoid allocation
/// and content copying operations, and is therefore significantly more efficient for repeated use than
/// {@link Recorder#GetIntervalHistogram()} and
/// {@link Recorder#getIntervalHistogramInto getIntervalHistogramInto()}. The provided
/// {@code histogramToRecycle} must
/// be either be null or an interval histogram returned by a previous call to
/// {@link Recorder#GetIntervalHistogram(Histogram histogramToRecycle)
/// GetIntervalHistogram(histogramToRecycle)} or
/// {@link Recorder#GetIntervalHistogram()}.
/// NOTE: The caller is responsible for not recycling the same returned interval histogram more than once. If
/// the same interval histogram instance is recycled more than once, behavior is undefined.
/// Calling {@link Recorder#GetIntervalHistogram(Histogram histogramToRecycle)
/// GetIntervalHistogram(histogramToRecycle)} will reset the value counts, and start accumulating value
/// counts for the next interval
/// </summary>
/// <param name="histogramToRecycle">
/// a previously returned interval histogram that may be recycled to avoid allocation and
/// copy operations.
/// </param>
/// <returns>a histogram containing the value counts accumulated since the last interval histogram was taken.</returns>
public HdrHistogram GetIntervalHistogram(HdrHistogram histogramToRecycle)
{
lock (syncLock)
{
if (histogramToRecycle == null)
{
histogramToRecycle = new InternalConcurrentHistogram(
instanceId,
inactiveHistogram.getNumberOfSignificantValueDigits());
}
// Verify that replacement histogram can validly be used as an inactive histogram replacement:
ValidateFitAsReplacementHistogram(histogramToRecycle);
try
{
recordingPhaser.ReaderLock();
inactiveHistogram = histogramToRecycle;
PerformIntervalSample();
return(inactiveHistogram);
}
finally
{
recordingPhaser.ReaderUnlock();
}
}
}
private void PerformIntervalSample()
{
inactiveHistogram.reset();
try
{
recordingPhaser.ReaderLock();
// Swap active and inactive histograms:
var tempHistogram = inactiveHistogram;
inactiveHistogram = activeHistogram;
activeHistogram = tempHistogram;
// Mark end time of previous interval and start time of new one:
var now = CurentTimeInMilis();
activeHistogram.setStartTimeStamp(now);
inactiveHistogram.setEndTimeStamp(now);
// Make sure we are not in the middle of recording a value on the previously active histogram:
// Flip phase to make sure no recordings that were in flight pre-flip are still active:
recordingPhaser.FlipPhase(500000L /* yield in 0.5 msec units if needed */);
}
finally
{
recordingPhaser.ReaderUnlock();
}
}
public override AbstractHistogram copyCorrectedForCoordinatedOmission(long expectedIntervalBetweenValueSamples)
{
var copy = new HdrHistogram(this);
copy.addWhileCorrectingForCoordinatedOmission(this, expectedIntervalBetweenValueSamples);
return(copy);
}
public override AbstractHistogram copy()
{
var copy = new HdrHistogram(this);
copy.add(this);
return(copy);
}
/// <summary>
/// Initializes a new instance of the <see cref="HdrHistogramReservoir" /> class.
/// </summary>
/// <param name="recorder">
/// Records integer values, and provides stable interval <see cref="Histogram">histogram</see> samples from
/// live recorded data without interrupting or stalling active recording of values
/// </param>
internal HdrHistogramReservoir(Recorder recorder)
{
_recorder = recorder;
_intervalHistogram = recorder.GetIntervalHistogram();
_runningTotals = new HdrHistogram.HdrHistogram(_intervalHistogram.NumberOfSignificantValueDigits);
}
private HdrHistogram.HdrHistogram UpdateTotals()
{
lock (_runningTotals)
{
_intervalHistogram = _recorder.GetIntervalHistogram(_intervalHistogram);
_runningTotals.add(_intervalHistogram);
return(_runningTotals.copy() as HdrHistogram.HdrHistogram);
}
}
private void ValidateFitAsReplacementHistogram(HdrHistogram replacementHistogram)
{
var replacementConcurrentHistogram = replacementHistogram as InternalConcurrentHistogram;
if (replacementConcurrentHistogram != null)
{
var activeConcurrentHistogram = activeHistogram as InternalConcurrentHistogram;
if (activeConcurrentHistogram != null &&
replacementConcurrentHistogram.ContainingInstanceId ==
activeConcurrentHistogram.ContainingInstanceId)
{
return;
}
}
throw new ArgumentException("replacement histogram must have been obtained via a previous" +
"GetIntervalHistogram() call from this " + GetType().Name + " instance");
}
/// <summary>
/// Construct an auto-resizing Recorder with a lowest discernible value of
/// 1 and an auto-adjusting highestTrackableValue. Can auto-resize up to track values up to (long.MaxValue / 2).
/// </summary>
/// <param name="numberOfSignificantValueDigits">
/// Specifies the precision to use. This is the number of significant decimal
/// digits to which the histogram will maintain value resolution and separation. Must be a non-negative integer between
/// 0 and 5.
/// </param>
public Recorder(int numberOfSignificantValueDigits)
{
activeHistogram = new InternalConcurrentHistogram(instanceId, numberOfSignificantValueDigits);
inactiveHistogram = new InternalConcurrentHistogram(instanceId, numberOfSignificantValueDigits);
activeHistogram.setStartTimeStamp(CurentTimeInMilis());
}
