tor-browser

The Tor Browser
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spinlock_benchmark.cc (2743B)

      1 // Copyright 2018 The Abseil Authors.
      2 //
      3 // Licensed under the Apache License, Version 2.0 (the "License");
      4 // you may not use this file except in compliance with the License.
      5 // You may obtain a copy of the License at
      6 //
      7 //      https://www.apache.org/licenses/LICENSE-2.0
      8 //
      9 // Unless required by applicable law or agreed to in writing, software
     10 // distributed under the License is distributed on an "AS IS" BASIS,
     11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     12 // See the License for the specific language governing permissions and
     13 // limitations under the License.
     14 
     15 // See also //absl/synchronization:mutex_benchmark for a comparison of SpinLock
     16 // and Mutex performance under varying levels of contention.
     17 
     18 #include "absl/base/internal/raw_logging.h"
     19 #include "absl/base/internal/scheduling_mode.h"
     20 #include "absl/base/internal/spinlock.h"
     21 #include "absl/base/no_destructor.h"
     22 #include "absl/synchronization/internal/create_thread_identity.h"
     23 #include "benchmark/benchmark.h"
     24 
     25 namespace {
     26 
     27 template <absl::base_internal::SchedulingMode scheduling_mode>
     28 static void BM_TryLock(benchmark::State& state) {
     29  // Ensure a ThreadIdentity is installed so that KERNEL_ONLY has an effect.
     30  ABSL_INTERNAL_CHECK(
     31      absl::synchronization_internal::GetOrCreateCurrentThreadIdentity() !=
     32          nullptr,
     33      "GetOrCreateCurrentThreadIdentity() failed");
     34 
     35  static absl::NoDestructor<absl::base_internal::SpinLock> spinlock(
     36      scheduling_mode);
     37  for (auto _ : state) {
     38    if (spinlock->TryLock()) spinlock->Unlock();
     39  }
     40 }
     41 
     42 template <absl::base_internal::SchedulingMode scheduling_mode>
     43 static void BM_SpinLock(benchmark::State& state) {
     44  // Ensure a ThreadIdentity is installed so that KERNEL_ONLY has an effect.
     45  ABSL_INTERNAL_CHECK(
     46      absl::synchronization_internal::GetOrCreateCurrentThreadIdentity() !=
     47          nullptr,
     48      "GetOrCreateCurrentThreadIdentity() failed");
     49 
     50  static absl::NoDestructor<absl::base_internal::SpinLock> spinlock(
     51      scheduling_mode);
     52  for (auto _ : state) {
     53    absl::base_internal::SpinLockHolder holder(spinlock.get());
     54  }
     55 }
     56 
     57 BENCHMARK_TEMPLATE(BM_SpinLock,
     58                   absl::base_internal::SCHEDULE_KERNEL_ONLY)
     59    ->UseRealTime()
     60    ->Threads(1)
     61    ->ThreadPerCpu();
     62 
     63 BENCHMARK_TEMPLATE(BM_SpinLock,
     64                   absl::base_internal::SCHEDULE_COOPERATIVE_AND_KERNEL)
     65    ->UseRealTime()
     66    ->Threads(1)
     67    ->ThreadPerCpu();
     68 
     69 BENCHMARK_TEMPLATE(BM_TryLock, absl::base_internal::SCHEDULE_KERNEL_ONLY)
     70    ->UseRealTime()
     71    ->Threads(1)
     72    ->ThreadPerCpu();
     73 
     74 BENCHMARK_TEMPLATE(BM_TryLock,
     75                   absl::base_internal::SCHEDULE_COOPERATIVE_AND_KERNEL)
     76    ->UseRealTime()
     77    ->Threads(1)
     78    ->ThreadPerCpu();
     79 
     80 }  // namespace