github.com/SagerNet/gvisor@v0.0.0-20210707092255-7731c139d75c/test/perf/linux/getpid_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 <sys/syscall.h>
    16  #include <unistd.h>
    17  
    18  #include "gtest/gtest.h"
    19  #include "benchmark/benchmark.h"
    20  
    21  namespace gvisor {
    22  namespace testing {
    23  
    24  namespace {
    25  
    26  void BM_Getpid(benchmark::State& state) {
    27    for (auto _ : state) {
    28      syscall(SYS_getpid);
    29    }
    30  }
    31  
    32  BENCHMARK(BM_Getpid);
    33  
    34  #ifdef __x86_64__
    35  
    36  #define SYSNO_STR1(x) #x
    37  #define SYSNO_STR(x) SYSNO_STR1(x)
    38  
    39  // BM_GetpidOpt uses the most often pattern of calling system calls:
    40  // mov $SYS_XXX, %eax; syscall.
    41  void BM_GetpidOpt(benchmark::State& state) {
    42    for (auto s : state) {
    43      __asm__("movl $" SYSNO_STR(SYS_getpid) ", %%eax\n"
    44              "syscall\n"
    45              : : : "rax", "rcx", "r11");
    46    }
    47  }
    48  
    49  BENCHMARK(BM_GetpidOpt);
    50  #endif  // __x86_64__
    51  
    52  }  // namespace
    53  
    54  }  // namespace testing
    55  }  // namespace gvisor