benchmark.c

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/*  cpufreq-bench CPUFreq microbenchmark
 *
 *  Copyright (C) 2008 Christian Kornacker <[email protected]>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include <stdio.h>
#include <unistd.h>
#include <math.h>

#include "config.h"
#include "system.h"
#include "benchmark.h"

/* Print out progress if we log into a file */
#define show_progress(total_time, progress_time)    \
if (config->output != stdout) {             \
    fprintf(stdout, "Progress: %02lu %%\r",     \
        (progress_time * 100) / total_time);    \
    fflush(stdout);                 \
}

unsigned int calculate_timespace(long load, struct config *config)
{
    int i;
    long long now, then;
    unsigned int estimated = GAUGECOUNT;
    unsigned int rounds = 0;
    unsigned int timed = 0;

    if (config->verbose)
        printf("calibrating load of %lius, please wait...\n", load);

    /* get the initial calculation time for a specific number of rounds */
    now = get_time();
    ROUNDS(estimated);
    then = get_time();

    timed = (unsigned int)(then - now);

    /* approximation of the wanted load time by comparing with the
     * initial calculation time */
    for (i = 0; i < 4; i++) {
        rounds = (unsigned int)(load * estimated / timed);
        dprintf("calibrating with %u rounds\n", rounds);
        now = get_time();
        ROUNDS(rounds);
        then = get_time();

        timed = (unsigned int)(then - now);
        estimated = rounds;
    }
    if (config->verbose)
        printf("calibration done\n");

    return estimated;
}

void start_benchmark(struct config *config)
{
    unsigned int _round, cycle;
    long long now, then;
    long sleep_time = 0, load_time = 0;
    long performance_time = 0, powersave_time = 0;
    unsigned int calculations;
    unsigned long total_time = 0, progress_time = 0;

    sleep_time = config->sleep;
    load_time = config->load;

    /* For the progress bar */
    for (_round = 1; _round <= config->rounds; _round++)
        total_time += _round * (config->sleep + config->load);
    total_time *= 2; /* powersave and performance cycles */

    for (_round = 0; _round < config->rounds; _round++) {
        performance_time = 0LL;
        powersave_time = 0LL;

        show_progress(total_time, progress_time);

        /* set the cpufreq governor to "performance" which disables
         * P-State switching. */
        if (set_cpufreq_governor("performance", config->cpu) != 0)
            return;

        /* calibrate the calculation time. the resulting calculation
         * _rounds should produce a load which matches the configured
         * load time */
        calculations = calculate_timespace(load_time, config);

        if (config->verbose)
            printf("_round %i: doing %u cycles with %u calculations"
                   " for %lius\n", _round + 1, config->cycles,
                   calculations, load_time);

        fprintf(config->output, "%u %li %li ",
            _round, load_time, sleep_time);

        if (config->verbose)
            printf("avarage: %lius, rps:%li\n",
                load_time / calculations,
                1000000 * calculations / load_time);

        /* do some sleep/load cycles with the performance governor */
        for (cycle = 0; cycle < config->cycles; cycle++) {
            now = get_time();
            usleep(sleep_time);
            ROUNDS(calculations);
            then = get_time();
            performance_time += then - now - sleep_time;
            if (config->verbose)
                printf("performance cycle took %lius, "
                    "sleep: %lius, "
                    "load: %lius, rounds: %u\n",
                    (long)(then - now), sleep_time,
                    load_time, calculations);
        }
        fprintf(config->output, "%li ",
            performance_time / config->cycles);

        progress_time += sleep_time + load_time;
        show_progress(total_time, progress_time);

        /* set the powersave governor which activates P-State switching
         * again */
        if (set_cpufreq_governor(config->governor, config->cpu) != 0)
            return;

        /* again, do some sleep/load cycles with the
         * powersave governor */
        for (cycle = 0; cycle < config->cycles; cycle++) {
            now = get_time();
            usleep(sleep_time);
            ROUNDS(calculations);
            then = get_time();
            powersave_time += then - now - sleep_time;
            if (config->verbose)
                printf("powersave cycle took %lius, "
                    "sleep: %lius, "
                    "load: %lius, rounds: %u\n",
                    (long)(then - now), sleep_time,
                    load_time, calculations);
        }

        progress_time += sleep_time + load_time;

        /* compare the avarage sleep/load cycles  */
        fprintf(config->output, "%li ",
            powersave_time / config->cycles);
        fprintf(config->output, "%.3f\n",
            performance_time * 100.0 / powersave_time);
        fflush(config->output);

        if (config->verbose)
            printf("performance is at %.2f%%\n",
                performance_time * 100.0 / powersave_time);

        sleep_time += config->sleep_step;
        load_time += config->load_step;
    }
}