108 lines
2.5 KiB
C
108 lines
2.5 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <time.h>
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#ifdef _WIN32
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#include <windows.h>
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#include <intrin.h>
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#else
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#include <unistd.h>
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#endif
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#include "clock.h"
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void start_counter(void);
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double get_counter(void);
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/*
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* Routines for using the cycle counter
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*/
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/* $begin x86cyclecounter */
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/* Initialize the cycle counter */
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static unsigned cyc_hi = 0;
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static unsigned cyc_lo = 0;
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/* Set *hi and *lo to the high and low order bits of the cycle counter.
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Implementation requires assembly code to use the rdtsc instruction. */
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void access_counter(unsigned* hi, unsigned* lo)
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{
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#ifdef _WIN32
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long long counter;
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counter = __rdtsc();
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(*hi) = (unsigned int)(counter >> 32);
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(*lo) = (unsigned int)counter;
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#else
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asm("rdtsc; movl %%edx,%0; movl %%eax,%1" /* Read cycle counter */
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: "=r" (*hi), "=r" (*lo) /* and move results to */
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: /* No input */ /* the two outputs */
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: "%edx", "%eax");
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#endif
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}
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/* Record the current value of the cycle counter. */
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void start_counter(void)
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{
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access_counter(&cyc_hi, &cyc_lo);
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}
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/* Return the number of cycles since the last call to start_counter. */
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double get_counter(void)
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{
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unsigned ncyc_hi, ncyc_lo;
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unsigned hi, lo, borrow;
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double result;
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/* Get cycle counter */
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access_counter(&ncyc_hi, &ncyc_lo);
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/* Do double precision subtraction */
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lo = ncyc_lo - cyc_lo;
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borrow = lo > ncyc_lo;
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hi = ncyc_hi - cyc_hi - borrow;
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result = (double)hi * (1 << 30) * 4 + lo;
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if (result < 0) {
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printf("[%s]错误！counter返回了负值：%.0f\n", __func__, result);
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}
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return result;
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}
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void make_CPU_busy(void)
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{
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volatile double old_tick, new_tick;
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start_counter();
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old_tick = get_counter();
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new_tick = get_counter();
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while (new_tick - old_tick < 1000000000)
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new_tick = get_counter();
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}
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/* $begin mhz */
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/* Estimate the clock rate by measuring the cycles that elapse */
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/* while sleeping for sleeptime seconds */
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double mhz_full(int verbose, int sleeptime)
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{
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double rate;
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if (verbose)
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printf("[%s]准备开始测量处理器性能，睡眠时间=%d秒\n", __func__, sleeptime);
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start_counter();
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#ifdef _WIN32
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Sleep(sleeptime * 1000);
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#else
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sleep(sleeptime);
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#endif
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rate = get_counter() / (1e6 * sleeptime);
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if (verbose)
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printf("[%s]处理器主频 ~= %.1f MHz\n", __func__, rate);
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return rate;
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}
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/* $end mhz */
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/* Version using a default sleeptime */
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double mhz(int verbose)
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{
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return mhz_full(verbose, 2);
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}
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