gvisor.dev/gvisor@v0.0.0-20240520182842-f9d4d51c7e0f/test/perf/linux/clock_gettime_benchmark.cc (about)

     1  // Copyright 2020 The gVisor 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  //     http://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  #include <pthread.h>
    16  #include <time.h>
    17  
    18  #include "gtest/gtest.h"
    19  #include "absl/time/clock.h"
    20  #include "absl/time/time.h"
    21  #include "benchmark/benchmark.h"
    22  
    23  namespace gvisor {
    24  namespace testing {
    25  
    26  namespace {
    27  
    28  void BM_ClockGettimeThreadCPUTime(benchmark::State& state) {
    29    clockid_t clockid;
    30    ASSERT_EQ(0, pthread_getcpuclockid(pthread_self(), &clockid));
    31    struct timespec tp;
    32  
    33    for (auto _ : state) {
    34      clock_gettime(clockid, &tp);
    35    }
    36  }
    37  
    38  BENCHMARK(BM_ClockGettimeThreadCPUTime);
    39  
    40  void BM_VDSOClockGettime(benchmark::State& state) {
    41    const clockid_t clock = state.range(0);
    42    struct timespec tp;
    43    absl::Time start = absl::Now();
    44  
    45    // Don't benchmark the calibration phase.
    46    while (absl::Now() < start + absl::Milliseconds(2100)) {
    47      clock_gettime(clock, &tp);
    48    }
    49  
    50    for (auto _ : state) {
    51      clock_gettime(clock, &tp);
    52    }
    53  }
    54  
    55  BENCHMARK(BM_VDSOClockGettime)->Arg(CLOCK_MONOTONIC)->Arg(CLOCK_REALTIME);
    56  
    57  }  // namespace
    58  
    59  }  // namespace testing
    60  }  // namespace gvisor