Measuring the CPU frequency scaling effect

问题

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?

回答1:

From the comment in my another post, in short, redtsc cannot use for measure the effect of cpu frequency scaling because the counter from the redtsc does not affected by the CPU frequency.

来源：https://stackoverflow.com/questions/19719317/measuring-the-cpu-frequency-scaling-effect