LXR linux/tools/power/cpupower/bench/system.c

   1/*  cpufreq-bench CPUFreq microbenchmark
   2 *
   3 *  Copyright (C) 2008 Christian Kornacker <ckornacker@suse.de>
   4 *
   5 *  This program is free software; you can redistribute it and/or modify
   6 *  it under the terms of the GNU General Public License as published by
   7 *  the Free Software Foundation; either version 2 of the License, or
   8 *  (at your option) any later version.
   9 *
  10 *  This program is distributed in the hope that it will be useful,
  11 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 *  GNU General Public License for more details.
  14 *
  15 *  You should have received a copy of the GNU General Public License
  16 *  along with this program; if not, write to the Free Software
  17 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  18 */
  19
  20#include <stdio.h>
  21#include <time.h>
  22#include <sys/time.h>
  23#include <sys/types.h>
  24#include <unistd.h>
  25
  26#include <sched.h>
  27
  28#include <cpufreq.h>
  29
  30#include "config.h"
  31#include "system.h"
  32
  33/**
  34 * returns time since epoch in µs
  35 *
  36 * @retval time
  37 **/
  38
  39long long int get_time()
  40{
  41        struct timeval now;
  42
  43        gettimeofday(&now, NULL);
  44
  45        return (long long int)(now.tv_sec * 1000000LL + now.tv_usec);
  46}
  47
  48/**
  49 * sets the cpufreq governor
  50 *
  51 * @param governor cpufreq governor name
  52 * @param cpu cpu for which the governor should be set
  53 *
  54 * @retval 0 on success
  55 * @retval -1 when failed
  56 **/
  57
  58int set_cpufreq_governor(char *governor, unsigned int cpu)
  59{
  60
  61        dprintf("set %s as cpufreq governor\n", governor);
  62
  63        if (cpufreq_cpu_exists(cpu) != 0) {
  64                perror("cpufreq_cpu_exists");
  65                fprintf(stderr, "error: cpu %u does not exist\n", cpu);
  66                return -1;
  67        }
  68
  69        if (cpufreq_modify_policy_governor(cpu, governor) != 0) {
  70                perror("cpufreq_modify_policy_governor");
  71                fprintf(stderr, "error: unable to set %s governor\n", governor);
  72                return -1;
  73        }
  74
  75        return 0;
  76}
  77
  78/**
  79 * sets cpu affinity for the process
  80 *
  81 * @param cpu cpu# to which the affinity should be set
  82 *
  83 * @retval 0 on success
  84 * @retval -1 when setting the affinity failed
  85 **/
  86
  87int set_cpu_affinity(unsigned int cpu)
  88{
  89        cpu_set_t cpuset;
  90
  91        CPU_ZERO(&cpuset);
  92        CPU_SET(cpu, &cpuset);
  93
  94        dprintf("set affinity to cpu #%u\n", cpu);
  95
  96        if (sched_setaffinity(getpid(), sizeof(cpu_set_t), &cpuset) < 0) {
  97                perror("sched_setaffinity");
  98                fprintf(stderr, "warning: unable to set cpu affinity\n");
  99                return -1;
 100        }
 101
 102        return 0;
 103}
 104
 105/**
 106 * sets the process priority parameter
 107 *
 108 * @param priority priority value
 109 *
 110 * @retval 0 on success
 111 * @retval -1 when setting the priority failed
 112 **/
 113
 114int set_process_priority(int priority)
 115{
 116        struct sched_param param;
 117
 118        dprintf("set scheduler priority to %i\n", priority);
 119
 120        param.sched_priority = priority;
 121
 122        if (sched_setscheduler(0, SCHEDULER, &param) < 0) {
 123                perror("sched_setscheduler");
 124                fprintf(stderr, "warning: unable to set scheduler priority\n");
 125                return -1;
 126        }
 127
 128        return 0;
 129}
 130
 131/**
 132 * notifies the user that the benchmark may run some time
 133 *
 134 * @param config benchmark config values
 135 *
 136 **/
 137
 138void prepare_user(const struct config *config)
 139{
 140        unsigned long sleep_time = 0;
 141        unsigned long load_time = 0;
 142        unsigned int round;
 143
 144        for (round = 0; round < config->rounds; round++) {
 145                sleep_time +=  2 * config->cycles *
 146                        (config->sleep + config->sleep_step * round);
 147                load_time += 2 * config->cycles *
 148                        (config->load + config->load_step * round) +
 149                        (config->load + config->load_step * round * 4);
 150        }
 151
 152        if (config->verbose || config->output != stdout)
 153                printf("approx. test duration: %im\n",
 154                       (int)((sleep_time + load_time) / 60000000));
 155}
 156
 157/**
 158 * sets up the cpu affinity and scheduler priority
 159 *
 160 * @param config benchmark config values
 161 *
 162 **/
 163
 164void prepare_system(const struct config *config)
 165{
 166        if (config->verbose)
 167                printf("set cpu affinity to cpu #%u\n", config->cpu);
 168
 169        set_cpu_affinity(config->cpu);
 170
 171        switch (config->prio) {
 172        case SCHED_HIGH:
 173                if (config->verbose)
 174                        printf("high priority condition requested\n");
 175
 176                set_process_priority(PRIORITY_HIGH);
 177                break;
 178        case SCHED_LOW:
 179                if (config->verbose)
 180                        printf("low priority condition requested\n");
 181
 182                set_process_priority(PRIORITY_LOW);
 183                break;
 184        default:
 185                if (config->verbose)
 186                        printf("default priority condition requested\n");
 187
 188                set_process_priority(PRIORITY_DEFAULT);
 189        }
 190}
 191
 192