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 #include <cpupower.h>
  30
  31 #include "config.h"
  32 #include "system.h"
  33
  34 /**
  35  * returns time since epoch in µs
  36  *
  37  * @retval time
  38  **/
  39
  40 long long int get_time()
  41 {
  42         struct timeval now;
  43
  44         gettimeofday(&now, NULL);
  45
  46         return (long long int)(now.tv_sec * 1000000LL + now.tv_usec);
  47 }
  48
  49 /**
  50  * sets the cpufreq governor
  51  *
  52  * @param governor cpufreq governor name
  53  * @param cpu cpu for which the governor should be set
  54  *
  55  * @retval 0 on success
  56  * @retval -1 when failed
  57  **/
  58
  59 int set_cpufreq_governor(char *governor, unsigned int cpu)
  60 {
  61
  62         dprintf("set %s as cpufreq governor\n", governor);
  63
  64         if (cpupower_is_cpu_online(cpu) != 0) {
  65                 perror("cpufreq_cpu_exists");
  66                 fprintf(stderr, "error: cpu %u does not exist\n", cpu);
  67                 return -1;
  68         }
  69
  70         if (cpufreq_modify_policy_governor(cpu, governor) != 0) {
  71                 perror("cpufreq_modify_policy_governor");
  72                 fprintf(stderr, "error: unable to set %s governor\n", governor);
  73                 return -1;
  74         }
  75
  76         return 0;
  77 }
  78
  79 /**
  80  * sets cpu affinity for the process
  81  *
  82  * @param cpu cpu# to which the affinity should be set
  83  *
  84  * @retval 0 on success
  85  * @retval -1 when setting the affinity failed
  86  **/
  87
  88 int set_cpu_affinity(unsigned int cpu)
  89 {
  90         cpu_set_t cpuset;
  91
  92         CPU_ZERO(&cpuset);
  93         CPU_SET(cpu, &cpuset);
  94
  95         dprintf("set affinity to cpu #%u\n", cpu);
  96
  97         if (sched_setaffinity(getpid(), sizeof(cpu_set_t), &cpuset) < 0) {
  98                 perror("sched_setaffinity");
  99                 fprintf(stderr, "warning: unable to set cpu affinity\n");
 100                 return -1;
 101         }
 102
 103         return 0;
 104 }
 105
 106 /**
 107  * sets the process priority parameter
 108  *
 109  * @param priority priority value
 110  *
 111  * @retval 0 on success
 112  * @retval -1 when setting the priority failed
 113  **/
 114
 115 int set_process_priority(int priority)
 116 {
 117         struct sched_param param;
 118
 119         dprintf("set scheduler priority to %i\n", priority);
 120
 121         param.sched_priority = priority;
 122
 123         if (sched_setscheduler(0, SCHEDULER, &param) < 0) {
 124                 perror("sched_setscheduler");
 125                 fprintf(stderr, "warning: unable to set scheduler priority\n");
 126                 return -1;
 127         }
 128
 129         return 0;
 130 }
 131
 132 /**
 133  * notifies the user that the benchmark may run some time
 134  *
 135  * @param config benchmark config values
 136  *
 137  **/
 138
 139 void prepare_user(const struct config *config)
 140 {
 141         unsigned long sleep_time = 0;
 142         unsigned long load_time = 0;
 143         unsigned int round;
 144
 145         for (round = 0; round < config->rounds; round++) {
 146                 sleep_time +=  2 * config->cycles *
 147                         (config->sleep + config->sleep_step * round);
 148                 load_time += 2 * config->cycles *
 149                         (config->load + config->load_step * round) +
 150                         (config->load + config->load_step * round * 4);
 151         }
 152
 153         if (config->verbose || config->output != stdout)
 154                 printf("approx. test duration: %im\n",
 155                        (int)((sleep_time + load_time) / 60000000));
 156 }
 157
 158 /**
 159  * sets up the cpu affinity and scheduler priority
 160  *
 161  * @param config benchmark config values
 162  *
 163  **/
 164
 165 void prepare_system(const struct config *config)
 166 {
 167         if (config->verbose)
 168                 printf("set cpu affinity to cpu #%u\n", config->cpu);
 169
 170         set_cpu_affinity(config->cpu);
 171
 172         switch (config->prio) {
 173         case SCHED_HIGH:
 174                 if (config->verbose)
 175                         printf("high priority condition requested\n");
 176
 177                 set_process_priority(PRIORITY_HIGH);
 178                 break;
 179         case SCHED_LOW:
 180                 if (config->verbose)
 181                         printf("low priority condition requested\n");
 182
 183                 set_process_priority(PRIORITY_LOW);
 184                 break;
 185         default:
 186                 if (config->verbose)
 187                         printf("default priority condition requested\n");
 188
 189                 set_process_priority(PRIORITY_DEFAULT);
 190         }
 191 }
 192