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>
BM_TryLock(benchmark::State & state)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>
BM_SpinLock(benchmark::State & state)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
81