| // Licensed to the Apache Software Foundation (ASF) under one |
| // or more contributor license agreements. See the NOTICE file |
| // distributed with this work for additional information |
| // regarding copyright ownership. The ASF licenses this file |
| // to you under the Apache License, Version 2.0 (the |
| // "License"); you may not use this file except in compliance |
| // with the License. You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, |
| // software distributed under the License is distributed on an |
| // "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| // KIND, either express or implied. See the License for the |
| // specific language governing permissions and limitations |
| // under the License. |
| |
| #include <cstdint> |
| #include <memory> |
| #include <thread> |
| #include <vector> |
| |
| #include <gflags/gflags.h> |
| #include <gtest/gtest.h> |
| |
| #include "kudu/util/hdr_histogram.h" |
| #include "kudu/util/monotime.h" |
| #include "kudu/util/test_util.h" |
| |
| DEFINE_int32(histogram_test_num_threads, 16, |
| "Number of threads to spawn for mt-hdr_histogram test"); |
| DEFINE_uint64(histogram_test_num_increments_per_thread, 100000LU, |
| "Number of times to call Increment() per thread in mt-hdr_histogram test"); |
| |
| using std::thread; |
| using std::unique_ptr; |
| using std::vector; |
| |
| namespace kudu { |
| |
| class MtHdrHistogramTest : public KuduTest { |
| public: |
| MtHdrHistogramTest() { |
| num_threads_ = FLAGS_histogram_test_num_threads; |
| num_times_ = FLAGS_histogram_test_num_increments_per_thread; |
| } |
| |
| protected: |
| int num_threads_; |
| uint64_t num_times_; |
| }; |
| |
| // Increment a counter a bunch of times in the same bucket |
| static void IncrementSameHistValue(HdrHistogram* hist, uint64_t value, uint64_t times) { |
| for (uint64_t i = 0; i < times; i++) { |
| hist->Increment(value); |
| } |
| } |
| |
| TEST_F(MtHdrHistogramTest, ConcurrentWriteTest) { |
| const uint64_t kValue = 1LU; |
| |
| HdrHistogram hist(100000LU, 3); |
| |
| vector<thread> threads; |
| threads.reserve(num_threads_); |
| for (int i = 0; i < num_threads_; i++) { |
| threads.emplace_back([this, &hist]() { |
| IncrementSameHistValue(&hist, kValue, this->num_times_); |
| }); |
| } |
| for (auto& t : threads) { |
| t.join(); |
| } |
| |
| HdrHistogram snapshot(hist); |
| ASSERT_EQ(num_threads_ * num_times_, snapshot.CountInBucketForValue(kValue)); |
| } |
| |
| // Copy while writing, then iterate to ensure copies are consistent. |
| TEST_F(MtHdrHistogramTest, ConcurrentCopyWhileWritingTest) { |
| const int kNumCopies = 10; |
| const uint64_t kValue = 1; |
| |
| HdrHistogram hist(100000LU, 3); |
| |
| vector<thread> threads; |
| threads.reserve(num_threads_); |
| for (int i = 0; i < num_threads_; i++) { |
| threads.emplace_back([this, &hist]() { |
| IncrementSameHistValue(&hist, kValue, this->num_times_); |
| }); |
| } |
| |
| // This is somewhat racy but the goal is to catch this issue at least |
| // most of the time. At the time of this writing, before fixing a bug where |
| // the total count stored in a copied histogram may not match its internal |
| // counts (under concurrent writes), this test fails for me on 100/100 runs. |
| vector<unique_ptr<HdrHistogram>> snapshots; |
| for (int i = 0; i < kNumCopies; i++) { |
| snapshots.emplace_back(new HdrHistogram(hist)); |
| SleepFor(MonoDelta::FromMicroseconds(100)); |
| } |
| for (int i = 0; i < kNumCopies; i++) { |
| snapshots[i]->MeanValue(); // Will crash if underlying iterator is inconsistent. |
| } |
| |
| for (auto& t : threads) { |
| t.join(); |
| } |
| } |
| |
| } // namespace kudu |