测量CPU频率缩放效果

Question

Recently I am trying to measure the effect of the cpu scaling. Is it accurate if I use this clock to measure it?

    template<std::intmax_t clock_freq>
    struct rdtsc_clock {
        typedef unsigned long long rep;
        typedef std::ratio<1, clock_freq> period;
        typedef std::chrono::duration<rep, period> duration;
        typedef std::chrono::time_point<rdtsc_clock> time_point;
        static const bool is_steady = true;

        static time_point now() noexcept
        {

            unsigned lo, hi;
            asm volatile("rdtsc" : "=a" (lo), "=d" (hi));

            return time_point(duration(static_cast<rep>(hi) << 32 | lo));
        }
    };

Update :

According to the comment from my another post , I believe redtsc cannot use for measure the effect of cpu frequency scaling because the counter from the redtsc does not affected by the CPU frequency, am i right?

Answer 1

简而言之，根据我另一篇文章中的评论，redtsc无法用于衡量cpu频率缩放的效果，因为redtsc的计数器不受CPU频率的影响。