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
  39 long 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
  58 int 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
  87 int 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
 114 int 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
 138 void 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
 164 void 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