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- /*
- * Copyright 2016-present Facebook, Inc.
- *
- * Licensed 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 <folly/synchronization/Baton.h>
- #include <thread>
- #include <folly/Benchmark.h>
- #include <folly/portability/Semaphore.h>
- #include <folly/synchronization/test/BatonTestHelpers.h>
- #include <folly/test/DeterministicSchedule.h>
- using namespace folly;
- using namespace folly::test;
- using folly::detail::EmulatedFutexAtomic;
- BENCHMARK(baton_pingpong_blocking, iters) {
- run_pingpong_test<true, std::atomic>(iters);
- }
- BENCHMARK(baton_pingpong_nonblocking, iters) {
- run_pingpong_test<false, std::atomic>(iters);
- }
- BENCHMARK_DRAW_LINE();
- BENCHMARK(baton_pingpong_emulated_futex_blocking, iters) {
- run_pingpong_test<true, EmulatedFutexAtomic>(iters);
- }
- BENCHMARK(baton_pingpong_emulated_futex_nonblocking, iters) {
- run_pingpong_test<false, EmulatedFutexAtomic>(iters);
- }
- BENCHMARK_DRAW_LINE();
- BENCHMARK(posix_sem_pingpong, iters) {
- sem_t sems[3];
- sem_t* a = sems + 0;
- sem_t* b = sems + 2; // to get it on a different cache line
- sem_init(a, 0, 0);
- sem_init(b, 0, 0);
- auto thr = std::thread([=] {
- for (size_t i = 0; i < iters; ++i) {
- sem_wait(a);
- sem_post(b);
- }
- });
- for (size_t i = 0; i < iters; ++i) {
- sem_post(a);
- sem_wait(b);
- }
- thr.join();
- }
- // I am omitting a benchmark result snapshot because these microbenchmarks
- // mainly illustrate that PreBlockAttempts is very effective for rapid
- // handoffs. The performance of Baton and sem_t is essentially identical
- // to the required futex calls for the blocking case
- int main(int argc, char** argv) {
- gflags::ParseCommandLineFlags(&argc, &argv, true);
- folly::runBenchmarks();
- return 0;
- }
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