From 24a55978075eade5bce4db633670bcc1599fc154 Mon Sep 17 00:00:00 2001 From: Yang Huiting <3552600665@qq.com> Date: Tue, 5 May 2026 22:52:06 +0800 Subject: [PATCH] =?UTF-8?q?=E6=B8=85=E7=A9=BAmaster=E9=87=8C=E7=9A=84?= =?UTF-8?q?=E6=97=A7=E4=BB=A3=E7=A0=81?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- shangji.cpp | 225 ---------------------------------------------------- 1 file changed, 225 deletions(-) delete mode 100644 shangji.cpp diff --git a/shangji.cpp b/shangji.cpp deleted file mode 100644 index 51623ce..0000000 --- a/shangji.cpp +++ /dev/null @@ -1,225 +0,0 @@ -#include -#include -#include -#include - -// 全局变量 -volatile int parking_spot_available = 1; -volatile int turn = 0; -volatile int flag[2] = { 0, 0 }; -volatile int success_count[3] = { 0, 0, 0 }; -volatile int cpu_usage[3] = { 0, 0, 0 }; // CPU占用计数器 -volatile int conflict_count = 0; - -// 算法A：值日法（单标志法） -DWORD WINAPI algorithm_a(LPVOID param) { - int thread_id = (int)param; - int attempts = 40; - for (int i = 0; i < attempts; i++) { - // 繁忙等待 - 等待轮到自己 - while (turn != thread_id) { - cpu_usage[thread_id]++; // 记录CPU占用 - } - // 进入临界区 - if (parking_spot_available) { - Sleep(5); // 模拟使用车位 - success_count[thread_id]++; - parking_spot_available = 0; - parking_spot_available = 1; - } - // 让下一个线程有机会 - turn = (thread_id + 1) % 3; - Sleep(1); - } - return 0; -} - -// 算法B：双标志检查法 -DWORD WINAPI algorithm_b(LPVOID param) { - int thread_id = (int)param; - int attempts = 40; - int local_conflicts = 0; - for (int i = 0; i < attempts; i++) { - int wait_count = 0; - int max_wait = 10000; - // 第一步：设置自己的标志为TRUE - flag[thread_id % 2] = 1; - // 第二步：检查其他线程的标志 - int other_thread = (thread_id + 1) % 3; - while (flag[other_thread % 2] && wait_count < max_wait) { - cpu_usage[thread_id]++; // 记录CPU占用 - wait_count++; - if (wait_count % 1000 == 0) { - Sleep(1); - } - } - if (wait_count >= max_wait) { - flag[thread_id % 2] = 0; - Sleep(10); - continue; - } - // 检查是否违反互斥 - if (!parking_spot_available) { - local_conflicts++; - conflict_count++; - } - // 进入临界区 - if (parking_spot_available) { - Sleep(5); - success_count[thread_id]++; - parking_spot_available = 0; - parking_spot_available = 1; - } - // 离开临界区 - flag[thread_id % 2] = 0; - Sleep(1); - } - return 0; -} - -// 算法C：Peterson算法 -DWORD WINAPI algorithm_c(LPVOID param) { - int thread_id = (int)param; - int attempts = 40; - if (thread_id == 2) { - // 第三个线程使用简单等待 - for (int i = 0; i < attempts; i++) { - while (!parking_spot_available) { - cpu_usage[thread_id]++; // 记录CPU占用 - } - if (parking_spot_available) { - Sleep(5); - success_count[thread_id]++; - parking_spot_available = 0; - parking_spot_available = 1; - } - Sleep(1); - } - return 0; - } - // 线程0和1使用Peterson算法 - for (int i = 0; i < attempts; i++) { - flag[thread_id] = 1; - turn = 1 - thread_id; - while (flag[1 - thread_id] && turn == 1 - thread_id) { - cpu_usage[thread_id]++; // 记录CPU占用 - } - if (parking_spot_available) { - Sleep(5); - success_count[thread_id]++; - parking_spot_available = 0; - parking_spot_available = 1; - } - flag[thread_id] = 0; - Sleep(1); - } - return 0; -} - -// 测试函数 -void test_algorithm(int algorithm_type) { - HANDLE threads[3]; - DWORD threadIDs[3]; - // 重置计数器 - for (int i = 0; i < 3; i++) { - success_count[i] = 0; - cpu_usage[i] = 0; - } - parking_spot_available = 1; - turn = 0; - flag[0] = 0; - flag[1] = 0; - conflict_count = 0; - - printf("\n=== 测试算法 %c ===\n", 'A' + algorithm_type - 1); - - // 创建线程 - for (int i = 0; i < 3; i++) { - switch (algorithm_type) { - case 1: - threads[i] = CreateThread(NULL, 0, algorithm_a, (LPVOID)i, 0, &threadIDs[i]); - break; - case 2: - threads[i] = CreateThread(NULL, 0, algorithm_b, (LPVOID)i, 0, &threadIDs[i]); - break; - case 3: - threads[i] = CreateThread(NULL, 0, algorithm_c, (LPVOID)i, 0, &threadIDs[i]); - break; - } - } - - // 等待所有线程完成 - WaitForMultipleObjects(3, threads, TRUE, INFINITE); - - // 输出结果 - printf("成功抢到次数:\n"); - printf(" 线程0: %d次\n", success_count[0]); - printf(" 线程1: %d次\n", success_count[1]); - printf(" 线程2: %d次\n", success_count[2]); - printf(" 总计: %d次\n", success_count[0] + success_count[1] + success_count[2]); - - printf("\nCPU占用(繁忙等待循环次数):\n"); - printf(" 线程0: %d次\n", cpu_usage[0]); - printf(" 线程1: %d次\n", cpu_usage[1]); - printf(" 线程2: %d次\n", cpu_usage[2]); - printf(" 总计: %d次\n", cpu_usage[0] + cpu_usage[1] + cpu_usage[2]); - - if (conflict_count > 0) { - printf("\n*** 检测到%d次冲突（违反互斥） ***\n", conflict_count); - } - - // 关闭线程句柄 - for (int i = 0; i < 3; i++) { - CloseHandle(threads[i]); - } -} - -int main() { - printf("=== 抢车位模拟实验 - 三种繁忙等待算法对比 ===\n"); - printf("量化指标: 成功抢到次数 & CPU占用(繁忙等待循环次数)\n"); - printf("实验配置: 3个线程，每个线程尝试40次，总共120次\n"); - - // 测试算法A - printf("\n算法A：值日法（单标志法）"); - printf("\n特点：严格轮流，保证互斥但效率低\n"); - test_algorithm(1); - - // 测试算法B - printf("\n算法B：双标志检查法"); - printf("\n特点：可能违反互斥，可能死锁\n"); - test_algorithm(2); - - // 测试算法C - printf("\n算法C：Peterson算法"); - printf("\n特点：保证互斥，不会死锁\n"); - test_algorithm(3); - - // 实验结果分析 - printf("\n=== 实验结果分析 ===\n"); - printf("\n1. 正确性对比（是否违反互斥）:\n"); - printf(" - 算法A: 保证互斥，无冲突\n"); - printf(" - 算法B: 可能违反互斥，出现冲突\n"); - printf(" - 算法C: 保证互斥，无冲突\n"); - - printf("\n2. 公平性对比（成功次数分布）:\n"); - printf(" - 算法A: 严格轮流，最公平\n"); - printf(" - 算法B: 分布不均，可能出现饥饿\n"); - printf(" - 算法C: 相对公平\n"); - - printf("\n3. CPU浪费程度对比（繁忙等待循环次数）:\n"); - printf(" - 算法A: CPU占用最高，浪费严重\n"); - printf(" - 算法B: CPU占用中等，但存在正确性问题\n"); - printf(" - 算法C: CPU占用相对较低，效率较好\n"); - - printf("\n4. 综合评估:\n"); - printf(" - 算法A: 正确性√ 公平性√ 但CPU浪费严重\n"); - printf(" - 算法B: 正确性× 公平性× CPU浪费中等\n"); - printf(" - 算法C: 正确性√ 公平性○ CPU浪费较低\n\n"); - - printf("\n5. 信号量/互斥锁的优势:\n"); - printf(" - 避免繁忙等待，CPU占用大幅降低\n"); - printf(" - 保证正确性和公平性\n"); - printf(" - 现代操作系统推荐使用\n"); - - return 0; -}