C++ メモリ プールと早期割り当てによるメモリ管理パフォーマンスの向上

#include <iostream>
#include <vector>

class MemoryPool {
private:
    std::vector<void*> freeBlocks;
    std::vector<void*> allocatedBlocks;
    size_t blockSize;
    size_t poolSize;

public:
    MemoryPool(size_t blockSize, size_t poolSize)
        : blockSize(blockSize), poolSize(poolSize) {
        for (size_t i = 0; i < poolSize; ++i) {
            freeBlocks.push_back(malloc(blockSize));
        }
    }

    ~MemoryPool() {
        for (auto block : allocatedBlocks) {
            free(block);
        }
    }

    void* allocate() {
        if (freeBlocks.empty()) {
            return nullptr;
        }
        void* block = freeBlocks.back();
        freeBlocks.pop_back();
        allocatedBlocks.push_back(block);
        return block;
    }

    void deallocate(void* block) {
        freeBlocks.push_back(block);
        allocatedBlocks.erase(std::remove(allocatedBlocks.begin(), allocatedBlocks.end(), block));
    }
};

int main() {
    MemoryPool pool(1024, 100);

    std::vector<void*> objects;
    for (size_t i = 0; i < 100; ++i) {
        objects.push_back(pool.allocate());
    }

    // 使用对象

    for (auto object : objects) {
        pool.deallocate(object);
    }

    return 0;
}

#include <iostream>
#include <vector>

std::vector<int> preallocatedMemory(1000000);

int main() {
    // 记录内存分配时间
    auto start = std::chrono::high_resolution_clock::now();

    std::vector<int> objects;
    for (size_t i = 0; i < 1000000; ++i) {
        objects.push_back(preallocatedMemory[i]);
    }

    // 计算内存分配时间
    auto end = std::chrono::high_resolution_clock::now();
    auto duration = std::chrono::duration_cast<std::chrono::milliseconds>(end - start).count();

    std::cout << "Memory allocation time: " << duration << " ms\n";

    return 0;
}