system.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 <time.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>

#include <sched.h>

#include <cpufreq.h>

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

long long int get_time()
{
    struct timeval now;

    gettimeofday(&now, NULL);

    return (long long int)(now.tv_sec * 1000000LL + now.tv_usec);
}

int set_cpufreq_governor(char *governor, unsigned int cpu)
{

    dprintf("set %s as cpufreq governor\n", governor);

    if (cpufreq_cpu_exists(cpu) != 0) {
        perror("cpufreq_cpu_exists");
        fprintf(stderr, "error: cpu %u does not exist\n", cpu);
        return -1;
    }

    if (cpufreq_modify_policy_governor(cpu, governor) != 0) {
        perror("cpufreq_modify_policy_governor");
        fprintf(stderr, "error: unable to set %s governor\n", governor);
        return -1;
    }

    return 0;
}

int set_cpu_affinity(unsigned int cpu)
{
    cpu_set_t cpuset;

    CPU_ZERO(&cpuset);
    CPU_SET(cpu, &cpuset);

    dprintf("set affinity to cpu #%u\n", cpu);

    if (sched_setaffinity(getpid(), sizeof(cpu_set_t), &cpuset) < 0) {
        perror("sched_setaffinity");
        fprintf(stderr, "warning: unable to set cpu affinity\n");
        return -1;
    }

    return 0;
}

int set_process_priority(int priority)
{
    struct sched_param param;

    dprintf("set scheduler priority to %i\n", priority);

    param.sched_priority = priority;

    if (sched_setscheduler(0, SCHEDULER, &param) < 0) {
        perror("sched_setscheduler");
        fprintf(stderr, "warning: unable to set scheduler priority\n");
        return -1;
    }

    return 0;
}

void prepare_user(const struct config *config)
{
    unsigned long sleep_time = 0;
    unsigned long load_time = 0;
    unsigned int round;

    for (round = 0; round < config->rounds; round++) {
        sleep_time +=  2 * config->cycles *
            (config->sleep + config->sleep_step * round);
        load_time += 2 * config->cycles *
            (config->load + config->load_step * round) +
            (config->load + config->load_step * round * 4);
    }

    if (config->verbose || config->output != stdout)
        printf("approx. test duration: %im\n",
               (int)((sleep_time + load_time) / 60000000));
}

void prepare_system(const struct config *config)
{
    if (config->verbose)
        printf("set cpu affinity to cpu #%u\n", config->cpu);

    set_cpu_affinity(config->cpu);

    switch (config->prio) {
    case SCHED_HIGH:
        if (config->verbose)
            printf("high priority condition requested\n");

        set_process_priority(PRIORITY_HIGH);
        break;
    case SCHED_LOW:
        if (config->verbose)
            printf("low priority condition requested\n");

        set_process_priority(PRIORITY_LOW);
        break;
    default:
        if (config->verbose)
            printf("default priority condition requested\n");

        set_process_priority(PRIORITY_DEFAULT);
    }
}