| public GetPercentile ( double percentile ) : int | ||
| percentile | double | |
| return | int | |
public void testRolling()
{
MockedClock time = new MockedClock();
RollingPercentileNumber p = new RollingPercentileNumber(time, timeInMilliseconds, numberOfBuckets, bucketDataLength, DynamicProperties.Factory.AsProperty(true));
p.AddValue(1000);
p.AddValue(1000);
p.AddValue(1000);
p.AddValue(2000);
Assert.Equal(1, p.GetBuckets().Count());
// no bucket turnover yet so percentile not yet generated
Assert.Equal(0, p.GetPercentile(50));
time.Increment(6000);
// still only 1 bucket until we touch it again
Assert.Equal(1, p.GetBuckets().Count());
// a bucket has been created so we have a new percentile
Assert.Equal(1000, p.GetPercentile(50));
// now 2 buckets since getting a percentile causes bucket retrieval
Assert.Equal(2, p.GetBuckets().Count());
p.AddValue(1000);
p.AddValue(500);
// should still be 2 buckets
Assert.Equal(2, p.GetBuckets().Count());
p.AddValue(200);
p.AddValue(200);
p.AddValue(1600);
p.AddValue(200);
p.AddValue(1600);
p.AddValue(1600);
// we haven't progressed to a new bucket so the percentile should be the same and ignore the most recent bucket
Assert.Equal(1000, p.GetPercentile(50));
// Increment to another bucket so we include all of the above in the PercentileSnapshot
time.Increment(6000);
// the rolling version should have the same data as creating a snapshot like this
PercentileSnapshot ps = new PercentileSnapshot(1000, 1000, 1000, 2000, 1000, 500, 200, 200, 1600, 200, 1600, 1600);
Assert.Equal(ps.GetPercentile(0.15), p.GetPercentile(0.15));
Assert.Equal(ps.GetPercentile(0.50), p.GetPercentile(0.50));
Assert.Equal(ps.GetPercentile(0.90), p.GetPercentile(0.90));
Assert.Equal(ps.GetPercentile(0.995), p.GetPercentile(0.995));
//Console.WriteLine("100th: " + ps.GetPercentile(100) + " " + p.GetPercentile(100));
//Console.WriteLine("99.5th: " + ps.GetPercentile(99.5) + " " + p.GetPercentile(99.5));
//Console.WriteLine("99th: " + ps.GetPercentile(99) + " " + p.GetPercentile(99));
//Console.WriteLine("90th: " + ps.GetPercentile(90) + " " + p.GetPercentile(90));
//Console.WriteLine("50th: " + ps.GetPercentile(50) + " " + p.GetPercentile(50));
//Console.WriteLine("10th: " + ps.GetPercentile(10) + " " + p.GetPercentile(10));
// mean = 1000+1000+1000+2000+1000+500+200+200+1600+200+1600+1600/12
Assert.Equal(991, ps.Mean);
}
public void testThreadSafety()
{
MockedClock time = new MockedClock();
RollingPercentileNumber p = new RollingPercentileNumber(time, 100, 25, 1000, DynamicProperties.Factory.AsProperty(true));
int NUM_THREADS = 1000;
int NUM_ITERATIONS = 1000000;
var tasks = new Task [NUM_THREADS];
long aggregateMetrics = 0; //same as a blackhole
Random r = new Random();
var token = new CancellationTokenSource();
var metricsPoller = Task.Run(() =>
{
while (!token.IsCancellationRequested)
{
Interlocked.Add(ref aggregateMetrics, p.Mean + p.GetPercentile(10) + p.GetPercentile(50) + p.GetPercentile(90));
//Console.WriteLine("AGGREGATE : " + p.GetPercentile(10) + " : " + p.GetPercentile(50) + " : " + p.GetPercentile(90));
}
});
for (int i = 0; i < NUM_THREADS; i++)
{
int threadId = i;
tasks[i] = Task.Run(() =>
{
for (int j = 1; j < NUM_ITERATIONS / NUM_THREADS + 1; j++)
{
int nextInt = r.Next(100);
p.AddValue(nextInt);
if (threadId == 0)
{
time.Increment(1);
}
}
});
}
if( !Task.WaitAll(tasks, 1000))
throw new Exception("Timeout on all threads writing percentiles");
token.Cancel();
Interlocked.Add(ref aggregateMetrics, p.Mean + p.GetPercentile(10) + p.GetPercentile(50) + p.GetPercentile(90));
//Console.WriteLine(p.Mean + " : " + p.GetPercentile(50) + " : " + p.GetPercentile(75) + " : " + p.GetPercentile(90) + " : " + p.GetPercentile(95) + " : " + p.GetPercentile(99));
}
public void testSampleDataOverTime1()
{
//Console.WriteLine("\n\n***************************** testSampleDataOverTime1 \n");
MockedClock time = new MockedClock();
RollingPercentileNumber p = new RollingPercentileNumber(time, timeInMilliseconds, numberOfBuckets, bucketDataLength, DynamicProperties.Factory.AsProperty(true));
int previousTime = 0;
for (int i = 0; i < SampleDataHolder1.data.Length/2; i++)
{
int timeInMillisecondsSinceStart = SampleDataHolder1.data[i,0];
int latency = SampleDataHolder1.data[i,1];
time.Increment(timeInMillisecondsSinceStart - previousTime);
previousTime = timeInMillisecondsSinceStart;
p.AddValue(latency);
}
//Console.WriteLine("0.01: " + p.GetPercentile(0.01));
//Console.WriteLine("Median: " + p.GetPercentile(50));
//Console.WriteLine("90th: " + p.GetPercentile(90));
//Console.WriteLine("99th: " + p.GetPercentile(99));
//Console.WriteLine("99.5th: " + p.GetPercentile(99.5));
//Console.WriteLine("99.99: " + p.GetPercentile(99.99));
//Console.WriteLine("Median: " + p.GetPercentile(50));
//Console.WriteLine("Median: " + p.GetPercentile(50));
//Console.WriteLine("Median: " + p.GetPercentile(50));
/*
* In a loop as a use case was found where very different values were calculated in subsequent requests.
*/
for (int i = 0; i < 10; i++)
{
if (p.GetPercentile(50) > 5)
{
throw new Exception("We expect around 2 but got: " + p.GetPercentile(50));
}
if (p.GetPercentile(99.5) < 20)
{
throw new Exception("We expect to see some high values over 20 but got: " + p.GetPercentile(99.5));
}
}
}
public void testSampleDataOverTime2()
{
//Console.WriteLine("\n\n***************************** testSampleDataOverTime2 \n");
MockedClock time = new MockedClock();
int previousTime = 0;
RollingPercentileNumber p = new RollingPercentileNumber(time, timeInMilliseconds, numberOfBuckets, bucketDataLength, DynamicProperties.Factory.AsProperty(true));
for (int i = 0; i < SampleDataHolder2.data.Length/2; i++)
{
int timeInMillisecondsSinceStart = SampleDataHolder2.data[i,0];
int latency = SampleDataHolder2.data[i,1];
time.Increment(timeInMillisecondsSinceStart - previousTime);
previousTime = timeInMillisecondsSinceStart;
p.AddValue(latency);
}
//Console.WriteLine("0.01: " + p.GetPercentile(0.01));
//Console.WriteLine("Median: " + p.GetPercentile(50));
//Console.WriteLine("90th: " + p.GetPercentile(90));
//Console.WriteLine("99th: " + p.GetPercentile(99));
//Console.WriteLine("99.5th: " + p.GetPercentile(99.5));
//Console.WriteLine("99.99: " + p.GetPercentile(99.99));
if (p.GetPercentile(50) > 90 || p.GetPercentile(50) < 50)
{
throw new Exception("We expect around 60-70 but got: " + p.GetPercentile(50));
}
if (p.GetPercentile(99) < 400)
{
throw new Exception("We expect to see some high values over 400 but got: " + p.GetPercentile(99));
}
}
public void testValueIsZeroAfterRollingWindowPassesAndNoTraffic()
{
MockedClock time = new MockedClock();
var p = new RollingPercentileNumber(time, timeInMilliseconds, numberOfBuckets, bucketDataLength, DynamicProperties.Factory.AsProperty(true));
p.AddValue(1000);
p.AddValue(1000);
p.AddValue(1000);
p.AddValue(2000);
p.AddValue(4000);
Assert.Equal(1, p.GetBuckets().Count());
// no bucket turnover yet so percentile not yet generated
Assert.Equal(0, p.GetPercentile(50));
time.Increment(6000);
// still only 1 bucket until we touch it again
Assert.Equal(1, p.GetBuckets().Count());
// a bucket has been created so we have a new percentile
Assert.Equal(1500, p.GetPercentile(50));
// let 1 minute pass
time.Increment(60000);
// no data in a minute should mean all buckets are empty (or reset) so we should not have any percentiles
Assert.Equal(0, p.GetPercentile(50));
}
