如何使用指令RDTSC测量程序执行时间

可以使用以下代码来使用指令RDTSC测量程序执行时间：

#include <iostream>
#include <chrono>

using namespace std;
using namespace std::chrono;

int main() {
    unsigned int cycles_low, cycles_high, cycles_low1, cycles_high1;
    __asm__ __volatile__("rdtsc" : "=a" (cycles_low), "=d" (cycles_high));
    // Your code to measure execution time goes here
    __asm__ __volatile__("rdtsc" : "=a" (cycles_low1), "=d" (cycles_high1));
    unsigned long long start = ((unsigned long long)cycles_high << 32) | cycles_low;
    unsigned long long end = ((unsigned long long)cycles_high1 << 32) | cycles_low1;
    cout << "Execution time: " << (end - start) << " cycles" << endl;
    return 0;
}

这段代码使用了内联汇编来执行RDTSC指令，然后在代码执行前后分别记录了时间戳，并计算出了两个时间戳之间的差值，即为程序的执行时间。