BenchMemoryOrderX86

BenchMemoryOrderX86.cpp

#include <atomic>
#include <iostream>

#define MEMORY_ORDER std::memory_order_relaxed
// #define MEMORY_ORDER std::memory_order_seq_cst

static constexpr int numberCount = 50;
static constexpr uint64_t targetValue  = 1'000'000'000;

static uint64_t getUsec()
{
    timespec t;
    clock_gettime(CLOCK_MONOTONIC, &t);
    return t.tv_sec * 1'000'000 + t.tv_nsec / 1000;
}

int workOrdered(std::atomic_uint64_t& value)
{
    uint64_t a = 0;
    for (uint64_t i = 0; i < targetValue; ++i)
    {
        ++a;
        value.store((uint64_t)&value, MEMORY_ORDER);
    }
    return a;
}

int main()
{
    std::atomic_uint64_t value(0);

    uint64_t t1 = getUsec();
    workOrdered(value);
    uint64_t duration = getUsec() - t1;

    std::cout << "Took " << duration << " us" << std::endl;
    return 0;
}