bench.cpp

#include <benchmark/benchmark.h>

void LockedAdd(benchmark::State& state) {
    unsigned int val;
    while (state.KeepRunning()) {
	asm volatile("lock addl $1, %[val]" : [val] "=m"(val));
	benchmark::DoNotOptimize(val);
    }
}

void SimpleAdd(benchmark::State& state) {
    unsigned int val;
    while (state.KeepRunning()) {
	asm volatile("addl $1, %[val]" : [val] "=m"(val));
	benchmark::DoNotOptimize(val);
    }
}

BENCHMARK(LockedAdd);
BENCHMARK(SimpleAdd);

BENCHMARK_MAIN();