/* cpufreq-bench CPUFreq microbenchmark * * Copyright (C) 2008 Christian Kornacker <ckornacker@suse.de> * * 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" /** * returns time since epoch in µs * * @retval time **/ long long int get_time() { struct timeval now; gettimeofday(&now, NULL); return (long long int)(now.tv_sec * 1000000LL + now.tv_usec); } /** * sets the cpufreq governor * * @param governor cpufreq governor name * @param cpu cpu for which the governor should be set * * @retval 0 on success * @retval -1 when failed **/ 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; } /** * sets cpu affinity for the process * * @param cpu cpu# to which the affinity should be set * * @retval 0 on success * @retval -1 when setting the affinity failed **/ 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; } /** * sets the process priority parameter * * @param priority priority value * * @retval 0 on success * @retval -1 when setting the priority failed **/ 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, ¶m) < 0) { perror("sched_setscheduler"); fprintf(stderr, "warning: unable to set scheduler priority\n"); return -1; } return 0; } /** * notifies the user that the benchmark may run some time * * @param config benchmark config values * **/ 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)); } /** * sets up the cpu affinity and scheduler priority * * @param config benchmark config values * **/ 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); } }