7aacab8ae0
- 924ba2a3f9fca695d73c6bf491d20669e2b96b8e Changed RawPtr to use std::addressof() instead of operato... by Abseil Team <absl-team@google.com> - e8cf67f9fa74d4c5632da35547025ad2301c6819 Import of CCTZ from GitHub. by Alex Strelnikov <strel@google.com> - 2ece8a96611afcddd7b91e0197dadb896248250c Abandon ".inc" files in favor of ".h" headers. by Jorg Brown <jorg@google.com> - 37f5ed5da4058f90fb3e6a2733fce5b1fd0aaedf Add exception safety tests for absl::optional<T> by Abseil Team <absl-team@google.com> - 337f995a866b8f905f64ca6b271b5fec8f248a60 Update WORKSPACE to grab specific commits of dependencies... by Alex Strelnikov <strel@google.com> - 93e5b134607a554993387ad913e6c1621606004b Release Charmap microbenchmark. by Alex Strelnikov <strel@google.com> - 95c2e29b6d93ec1334484ee37d91f63101c45307 Release OStringStream microbenchmarks. by Alex Strelnikov <strel@google.com> - 250f51839ed26dd1e6b658d35aa291413e5f4825 Internal change by Greg Falcon <gfalcon@google.com> - ce34900fa3d1a95a8446bc943cdd801fac95be25 Improve compatibility of cctz cc_test targets for portabl... by Shaindel Schwartz <shaindel@google.com> - ce7e31dbf2c1ee93c79aae5b7dc7c603cb4babcf Improve portability of cc_tests. (Mark more tests that ca... by Abseil Team <absl-team@google.com> - dfcd4e455923703c1a1dcd523c5f915f7990fa2a Accept strings with custom allocators as arguments to abs... by Greg Falcon <gfalcon@google.com> - 2946b41ed3d5b8b5a8dc11182e443cf1ab6e3bde Link against benchmark_main instead of using BENCHMARK_MA... by Alex Strelnikov <strel@google.com> - f09de9e03bf8edd363069c4b352d8009423f531c Adds link to doc about the formats allowed by SimpleAtof(... by Greg Miller <jgm@google.com> - 59b0977e7a308e0800277886cf60226b2cc426a1 Simplify the HideMask() calculation so that it doesn't us... by Jorg Brown <jorg@google.com> GitOrigin-RevId: e2f6b8ac647271815b4fed2991f405524dd762c3 Change-Id: Ib9c8547ed7fe217fad6cb3ab1362e96181aa5cfa
94 lines
2.8 KiB
C++
94 lines
2.8 KiB
C++
// Copyright 2017 The Abseil Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include <vector>
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#include "benchmark/benchmark.h"
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#include "absl/base/internal/sysinfo.h"
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#include "absl/synchronization/blocking_counter.h"
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#include "absl/synchronization/internal/thread_pool.h"
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#include "absl/synchronization/mutex.h"
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namespace {
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// Measure the overhead of conditions on mutex release (when they must be
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// evaluated). Mutex has (some) support for equivalence classes allowing
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// Conditions with the same function/argument to potentially not be multiply
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// evaluated.
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//
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// num_classes==0 is used for the special case of every waiter being distinct.
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void BM_ConditionWaiters(benchmark::State& state) {
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int num_classes = state.range(0);
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int num_waiters = state.range(1);
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struct Helper {
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static void Waiter(absl::BlockingCounter* init, absl::Mutex* m, int* p) {
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init->DecrementCount();
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m->LockWhen(absl::Condition(
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static_cast<bool (*)(int*)>([](int* v) { return *v == 0; }), p));
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m->Unlock();
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}
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};
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if (num_classes == 0) {
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// No equivalence classes.
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num_classes = num_waiters;
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}
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absl::BlockingCounter init(num_waiters);
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absl::Mutex mu;
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std::vector<int> equivalence_classes(num_classes, 1);
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// Must be declared last to be destroyed first.
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absl::synchronization_internal::ThreadPool pool(num_waiters);
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for (int i = 0; i < num_waiters; i++) {
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// Mutex considers Conditions with the same function and argument
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// to be equivalent.
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pool.Schedule([&, i] {
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Helper::Waiter(&init, &mu, &equivalence_classes[i % num_classes]);
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});
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}
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init.Wait();
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for (auto _ : state) {
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mu.Lock();
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mu.Unlock(); // Each unlock requires Condition evaluation for our waiters.
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}
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mu.Lock();
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for (int i = 0; i < num_classes; i++) {
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equivalence_classes[i] = 0;
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}
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mu.Unlock();
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}
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#ifdef THREAD_SANITIZER
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// ThreadSanitizer can't handle 8192 threads.
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constexpr int kMaxConditionWaiters = 2048;
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#else
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constexpr int kMaxConditionWaiters = 8192;
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#endif
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BENCHMARK(BM_ConditionWaiters)->RangePair(0, 2, 1, kMaxConditionWaiters);
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void BM_ContendedMutex(benchmark::State& state) {
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static absl::Mutex* mu = new absl::Mutex;
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for (auto _ : state) {
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absl::MutexLock lock(mu);
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}
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}
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BENCHMARK(BM_ContendedMutex)->Threads(1);
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BENCHMARK(BM_ContendedMutex)->ThreadPerCpu();
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} // namespace
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