First taste of google/benchmark

Today, I tried google/benchmark. The build process is idiomatic:

# git clone https://github.com/google/benchmark.git
# git clone https://github.com/google/googletest.git benchmark/googletest
# cd benchmark/
# mkdir build
# cd build/
# cmake ..
# make

But the “make test” generates an error (please refer this issue). Write a simple test.cc:

# cat test.cc
#include <benchmark/benchmark.h>

static void BM_StringCreation(benchmark::State& state) {
  for (auto _ : state)
    std::string empty_string;
}
// Register the function as a benchmark
BENCHMARK(BM_StringCreation);

// Define another benchmark
static void BM_StringCopy(benchmark::State& state) {
  std::string x = "hello";
  for (auto _ : state)
    std::string copy(x);
}
BENCHMARK(BM_StringCopy);

BENCHMARK_MAIN();

Build and run it:

# g++ -pthread test.cc -o test -lbenchmark
# ./test
2018-04-30 18:14:59
Running ./test
Run on (2 X 2394 MHz CPU s)
CPU Caches:
  L1 Data 32K (x2)
  L1 Instruction 32K (x2)
  L2 Unified 4096K (x1)
***WARNING*** CPU scaling is enabled, the benchmark real time measurements may be noisy and will incur extra overhead.
***WARNING*** Library was built as DEBUG. Timings may be affected.
---------------------------------------------------------
Benchmark                  Time           CPU Iterations
---------------------------------------------------------
BM_StringCreation         10 ns         10 ns   71084124
BM_StringCopy             52 ns         52 ns   10000000

Maybe I will take a plunge in this project further.