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// SPDX-License-Identifier: GPL-2.0-or-later
/* cpufreq-bench CPUFreq microbenchmark
*
* Copyright (C) 2008 Christian Kornacker <ckornacker@suse.de>
*/
#include <stdio.h>
#include <time.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>
#include <sched.h>
#include <cpufreq.h>
#include <cpupower.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 (cpupower_is_cpu_online(cpu) != 1) {
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);
}
}
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