test_malloc.c

/* Test malloc and free performance over time for a specified allocation block size and total. */

#include <iostream>
#include <chrono>
#include <thread>
#include <cstring>

#if 0 // test HeapCompact (1/2)
#ifdef _WIN32
#include <Windows.h>
#endif
#endif

int main()
{
    const ptrdiff_t sz = 64 * 1024;
    const ptrdiff_t nb = ((ptrdiff_t)8 * 1024 * 1024 * 1024) / sz; // 8GB
    void **blocks = new void *[nb];
    std::chrono::time_point<std::chrono::steady_clock> t0 = std::chrono::steady_clock::now();
    int64_t ms;
    auto delta = [&]() -> int64_t {
        std::chrono::time_point<std::chrono::steady_clock> t1 = std::chrono::steady_clock::now();
        int64_t res = std::chrono::duration_cast<std::chrono::milliseconds>(t1 - t0).count();
        t0 = t1;
        return res;
    };

    std::cout << "round,malloc,free" << std::endl;

    for (ptrdiff_t r = 0; r < 16; ++r)
    {
#if 1
        std::cout << r << ",";
        delta();
        for (ptrdiff_t i = 0; i < nb; ++i)
        {
            blocks[i] = malloc(sz);
            // std::cout << blocks[i] << std::endl;
            memset(blocks[i], 42, sz);
        }
        ms = delta();
        std::cout << ms << ",";
#if 0 // immediate deallocation
        delta();
        for (ptrdiff_t i = 0; i < nb; ++i)
        {
            void *a = malloc(sz);
            // std::cout << blocks[i] << std::endl;
            memset(a, 42, sz);
            free(a);
        }
        ms = delta();
        std::cout << ms << ",";
#endif
        delta();
#if 0 // reverse deallocation order
        for (ptrdiff_t i = nb - 1; i >= 0; --i)
#else
        for (ptrdiff_t i = 0; i < nb; ++i)
#endif
        {
            free(blocks[i]);
        }
        ms = delta();
        std::cout << ms;
        delta();
#endif
#if 0 // test HeapCompact (2/2)
        delta();
        HeapCompact(GetProcessHeap(), 0);
        ms = delta();
        std::cout << "," << ms;
#endif
        std::cout << std::endl;
#if 0 // alternate with -32B allocation
        std::cout << r << "_B,";
        delta();
        for (ptrdiff_t i = 0; i < nb; ++i)
        {
            blocks[i] = malloc(sz - 32);
            // std::cout << blocks[i] << std::endl;
            memset(blocks[i], 42, sz - 32);
        }
        ms = delta();
        std::cout << ms << ",";
        for (ptrdiff_t i = 0; i < nb; ++i)
        {
            free(blocks[i]);
        }
        ms = delta();
        std::cout << ms << std::endl;
#endif
    }

    delete[] blocks;
}

/* end of file */