mirror of
https://github.com/facebook/rocksdb.git
synced 2024-11-25 14:31:35 +00:00
3b9a000c15
Summary:
I spent too much time thinking about histograms lately and realized boundary values fall into the lower bucket, not the upper bucket. It's because we're using `std::map::lower_bound` here: 867fe92e5e/monitoring/histogram.cc (L53). Fixed histogram's `ToString()` to reflect this.
Closes https://github.com/facebook/rocksdb/pull/2817
Differential Revision: D5751159
Pulled By: ajkr
fbshipit-source-id: 67432bb45849eec9b5bcc0d095551dbc0ee81766
222 lines
7.1 KiB
C++
222 lines
7.1 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
|
|
// This source code is licensed under both the GPLv2 (found in the
|
|
// COPYING file in the root directory) and Apache 2.0 License
|
|
// (found in the LICENSE.Apache file in the root directory).
|
|
//
|
|
#include <cmath>
|
|
|
|
#include "monitoring/histogram.h"
|
|
#include "monitoring/histogram_windowing.h"
|
|
#include "util/testharness.h"
|
|
|
|
namespace rocksdb {
|
|
|
|
class HistogramTest : public testing::Test {};
|
|
|
|
namespace {
|
|
const double kIota = 0.1;
|
|
const HistogramBucketMapper bucketMapper;
|
|
Env* env = Env::Default();
|
|
}
|
|
|
|
void PopulateHistogram(Histogram& histogram,
|
|
uint64_t low, uint64_t high, uint64_t loop = 1) {
|
|
for (; loop > 0; loop--) {
|
|
for (uint64_t i = low; i <= high; i++) {
|
|
histogram.Add(i);
|
|
}
|
|
}
|
|
}
|
|
|
|
void BasicOperation(Histogram& histogram) {
|
|
PopulateHistogram(histogram, 1, 110, 10); // fill up to bucket [70, 110)
|
|
|
|
HistogramData data;
|
|
histogram.Data(&data);
|
|
|
|
ASSERT_LE(fabs(histogram.Percentile(100.0) - 110.0), kIota);
|
|
ASSERT_LE(fabs(data.percentile99 - 108.9), kIota); // 99 * 110 / 100
|
|
ASSERT_LE(fabs(data.percentile95 - 104.5), kIota); // 95 * 110 / 100
|
|
ASSERT_LE(fabs(data.median - 55.0), kIota); // 50 * 110 / 100
|
|
ASSERT_EQ(data.average, 55.5); // (1 + 110) / 2
|
|
}
|
|
|
|
void MergeHistogram(Histogram& histogram, Histogram& other) {
|
|
PopulateHistogram(histogram, 1, 100);
|
|
PopulateHistogram(other, 101, 250);
|
|
histogram.Merge(other);
|
|
|
|
HistogramData data;
|
|
histogram.Data(&data);
|
|
|
|
ASSERT_LE(fabs(histogram.Percentile(100.0) - 250.0), kIota);
|
|
ASSERT_LE(fabs(data.percentile99 - 247.5), kIota); // 99 * 250 / 100
|
|
ASSERT_LE(fabs(data.percentile95 - 237.5), kIota); // 95 * 250 / 100
|
|
ASSERT_LE(fabs(data.median - 125.0), kIota); // 50 * 250 / 100
|
|
ASSERT_EQ(data.average, 125.5); // (1 + 250) / 2
|
|
}
|
|
|
|
void EmptyHistogram(Histogram& histogram) {
|
|
ASSERT_EQ(histogram.min(), bucketMapper.LastValue());
|
|
ASSERT_EQ(histogram.max(), 0);
|
|
ASSERT_EQ(histogram.num(), 0);
|
|
ASSERT_EQ(histogram.Median(), 0.0);
|
|
ASSERT_EQ(histogram.Percentile(85.0), 0.0);
|
|
ASSERT_EQ(histogram.Average(), 0.0);
|
|
ASSERT_EQ(histogram.StandardDeviation(), 0.0);
|
|
}
|
|
|
|
void ClearHistogram(Histogram& histogram) {
|
|
for (uint64_t i = 1; i <= 100; i++) {
|
|
histogram.Add(i);
|
|
}
|
|
histogram.Clear();
|
|
ASSERT_TRUE(histogram.Empty());
|
|
ASSERT_EQ(histogram.Median(), 0);
|
|
ASSERT_EQ(histogram.Percentile(85.0), 0);
|
|
ASSERT_EQ(histogram.Average(), 0);
|
|
}
|
|
|
|
TEST_F(HistogramTest, BasicOperation) {
|
|
HistogramImpl histogram;
|
|
BasicOperation(histogram);
|
|
|
|
HistogramWindowingImpl histogramWindowing;
|
|
BasicOperation(histogramWindowing);
|
|
}
|
|
|
|
TEST_F(HistogramTest, BoundaryValue) {
|
|
HistogramImpl histogram;
|
|
// - both should be in [0, 1] bucket because we place values on bucket
|
|
// boundaries in the lower bucket.
|
|
// - all points are in [0, 1] bucket, so p50 will be 0.5
|
|
// - the test cannot be written with a single point since histogram won't
|
|
// report percentiles lower than the min or greater than the max.
|
|
histogram.Add(0);
|
|
histogram.Add(1);
|
|
|
|
ASSERT_LE(fabs(histogram.Percentile(50.0) - 0.5), kIota);
|
|
}
|
|
|
|
TEST_F(HistogramTest, MergeHistogram) {
|
|
HistogramImpl histogram;
|
|
HistogramImpl other;
|
|
MergeHistogram(histogram, other);
|
|
|
|
HistogramWindowingImpl histogramWindowing;
|
|
HistogramWindowingImpl otherWindowing;
|
|
MergeHistogram(histogramWindowing, otherWindowing);
|
|
}
|
|
|
|
TEST_F(HistogramTest, EmptyHistogram) {
|
|
HistogramImpl histogram;
|
|
EmptyHistogram(histogram);
|
|
|
|
HistogramWindowingImpl histogramWindowing;
|
|
EmptyHistogram(histogramWindowing);
|
|
}
|
|
|
|
TEST_F(HistogramTest, ClearHistogram) {
|
|
HistogramImpl histogram;
|
|
ClearHistogram(histogram);
|
|
|
|
HistogramWindowingImpl histogramWindowing;
|
|
ClearHistogram(histogramWindowing);
|
|
}
|
|
|
|
TEST_F(HistogramTest, HistogramWindowingExpire) {
|
|
uint64_t num_windows = 3;
|
|
int micros_per_window = 1000000;
|
|
uint64_t min_num_per_window = 0;
|
|
|
|
HistogramWindowingImpl
|
|
histogramWindowing(num_windows, micros_per_window, min_num_per_window);
|
|
|
|
PopulateHistogram(histogramWindowing, 1, 1, 100);
|
|
env->SleepForMicroseconds(micros_per_window);
|
|
ASSERT_EQ(histogramWindowing.num(), 100);
|
|
ASSERT_EQ(histogramWindowing.min(), 1);
|
|
ASSERT_EQ(histogramWindowing.max(), 1);
|
|
ASSERT_EQ(histogramWindowing.Average(), 1);
|
|
|
|
PopulateHistogram(histogramWindowing, 2, 2, 100);
|
|
env->SleepForMicroseconds(micros_per_window);
|
|
ASSERT_EQ(histogramWindowing.num(), 200);
|
|
ASSERT_EQ(histogramWindowing.min(), 1);
|
|
ASSERT_EQ(histogramWindowing.max(), 2);
|
|
ASSERT_EQ(histogramWindowing.Average(), 1.5);
|
|
|
|
PopulateHistogram(histogramWindowing, 3, 3, 100);
|
|
env->SleepForMicroseconds(micros_per_window);
|
|
ASSERT_EQ(histogramWindowing.num(), 300);
|
|
ASSERT_EQ(histogramWindowing.min(), 1);
|
|
ASSERT_EQ(histogramWindowing.max(), 3);
|
|
ASSERT_EQ(histogramWindowing.Average(), 2.0);
|
|
|
|
// dropping oldest window with value 1, remaining 2 ~ 4
|
|
PopulateHistogram(histogramWindowing, 4, 4, 100);
|
|
env->SleepForMicroseconds(micros_per_window);
|
|
ASSERT_EQ(histogramWindowing.num(), 300);
|
|
ASSERT_EQ(histogramWindowing.min(), 2);
|
|
ASSERT_EQ(histogramWindowing.max(), 4);
|
|
ASSERT_EQ(histogramWindowing.Average(), 3.0);
|
|
|
|
// dropping oldest window with value 2, remaining 3 ~ 5
|
|
PopulateHistogram(histogramWindowing, 5, 5, 100);
|
|
env->SleepForMicroseconds(micros_per_window);
|
|
ASSERT_EQ(histogramWindowing.num(), 300);
|
|
ASSERT_EQ(histogramWindowing.min(), 3);
|
|
ASSERT_EQ(histogramWindowing.max(), 5);
|
|
ASSERT_EQ(histogramWindowing.Average(), 4.0);
|
|
}
|
|
|
|
TEST_F(HistogramTest, HistogramWindowingMerge) {
|
|
uint64_t num_windows = 3;
|
|
int micros_per_window = 1000000;
|
|
uint64_t min_num_per_window = 0;
|
|
|
|
HistogramWindowingImpl
|
|
histogramWindowing(num_windows, micros_per_window, min_num_per_window);
|
|
HistogramWindowingImpl
|
|
otherWindowing(num_windows, micros_per_window, min_num_per_window);
|
|
|
|
PopulateHistogram(histogramWindowing, 1, 1, 100);
|
|
PopulateHistogram(otherWindowing, 1, 1, 100);
|
|
env->SleepForMicroseconds(micros_per_window);
|
|
|
|
PopulateHistogram(histogramWindowing, 2, 2, 100);
|
|
PopulateHistogram(otherWindowing, 2, 2, 100);
|
|
env->SleepForMicroseconds(micros_per_window);
|
|
|
|
PopulateHistogram(histogramWindowing, 3, 3, 100);
|
|
PopulateHistogram(otherWindowing, 3, 3, 100);
|
|
env->SleepForMicroseconds(micros_per_window);
|
|
|
|
histogramWindowing.Merge(otherWindowing);
|
|
ASSERT_EQ(histogramWindowing.num(), 600);
|
|
ASSERT_EQ(histogramWindowing.min(), 1);
|
|
ASSERT_EQ(histogramWindowing.max(), 3);
|
|
ASSERT_EQ(histogramWindowing.Average(), 2.0);
|
|
|
|
// dropping oldest window with value 1, remaining 2 ~ 4
|
|
PopulateHistogram(histogramWindowing, 4, 4, 100);
|
|
env->SleepForMicroseconds(micros_per_window);
|
|
ASSERT_EQ(histogramWindowing.num(), 500);
|
|
ASSERT_EQ(histogramWindowing.min(), 2);
|
|
ASSERT_EQ(histogramWindowing.max(), 4);
|
|
|
|
// dropping oldest window with value 2, remaining 3 ~ 5
|
|
PopulateHistogram(histogramWindowing, 5, 5, 100);
|
|
env->SleepForMicroseconds(micros_per_window);
|
|
ASSERT_EQ(histogramWindowing.num(), 400);
|
|
ASSERT_EQ(histogramWindowing.min(), 3);
|
|
ASSERT_EQ(histogramWindowing.max(), 5);
|
|
}
|
|
|
|
} // namespace rocksdb
|
|
|
|
int main(int argc, char** argv) {
|
|
::testing::InitGoogleTest(&argc, argv);
|
|
return RUN_ALL_TESTS();
|
|
}
|