1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* cpufreq-bench CPUFreq microbenchmark
4 * Copyright (C) 2008 Christian Kornacker <ckornacker@suse.de>
10 #include <sys/types.h>
22 * returns time since epoch in µs
27 long long int get_time()
31 gettimeofday(&now, NULL);
33 return (long long int)(now.tv_sec * 1000000LL + now.tv_usec);
37 * sets the cpufreq governor
39 * @param governor cpufreq governor name
40 * @param cpu cpu for which the governor should be set
42 * @retval 0 on success
43 * @retval -1 when failed
46 int set_cpufreq_governor(char *governor, unsigned int cpu)
49 dprintf("set %s as cpufreq governor\n", governor);
51 if (cpupower_is_cpu_online(cpu) != 1) {
52 perror("cpufreq_cpu_exists");
53 fprintf(stderr, "error: cpu %u does not exist\n", cpu);
57 if (cpufreq_modify_policy_governor(cpu, governor) != 0) {
58 perror("cpufreq_modify_policy_governor");
59 fprintf(stderr, "error: unable to set %s governor\n", governor);
67 * sets cpu affinity for the process
69 * @param cpu cpu# to which the affinity should be set
71 * @retval 0 on success
72 * @retval -1 when setting the affinity failed
75 int set_cpu_affinity(unsigned int cpu)
80 CPU_SET(cpu, &cpuset);
82 dprintf("set affinity to cpu #%u\n", cpu);
84 if (sched_setaffinity(getpid(), sizeof(cpu_set_t), &cpuset) < 0) {
85 perror("sched_setaffinity");
86 fprintf(stderr, "warning: unable to set cpu affinity\n");
94 * sets the process priority parameter
96 * @param priority priority value
98 * @retval 0 on success
99 * @retval -1 when setting the priority failed
102 int set_process_priority(int priority)
104 struct sched_param param;
106 dprintf("set scheduler priority to %i\n", priority);
108 param.sched_priority = priority;
110 if (sched_setscheduler(0, SCHEDULER, ¶m) < 0) {
111 perror("sched_setscheduler");
112 fprintf(stderr, "warning: unable to set scheduler priority\n");
120 * notifies the user that the benchmark may run some time
122 * @param config benchmark config values
126 void prepare_user(const struct config *config)
128 unsigned long sleep_time = 0;
129 unsigned long load_time = 0;
132 for (round = 0; round < config->rounds; round++) {
133 sleep_time += 2 * config->cycles *
134 (config->sleep + config->sleep_step * round);
135 load_time += 2 * config->cycles *
136 (config->load + config->load_step * round) +
137 (config->load + config->load_step * round * 4);
140 if (config->verbose || config->output != stdout)
141 printf("approx. test duration: %im\n",
142 (int)((sleep_time + load_time) / 60000000));
146 * sets up the cpu affinity and scheduler priority
148 * @param config benchmark config values
152 void prepare_system(const struct config *config)
155 printf("set cpu affinity to cpu #%u\n", config->cpu);
157 set_cpu_affinity(config->cpu);
159 switch (config->prio) {
162 printf("high priority condition requested\n");
164 set_process_priority(PRIORITY_HIGH);
168 printf("low priority condition requested\n");
170 set_process_priority(PRIORITY_LOW);
174 printf("default priority condition requested\n");
176 set_process_priority(PRIORITY_DEFAULT);