1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*  cpufreq-bench CPUFreq microbenchmark
3  *
4  *  Copyright (C) 2008 Christian Kornacker <ckornacker@suse.de>
5  */
6 
7 #include <stdio.h>
8 #include <time.h>
9 #include <sys/time.h>
10 #include <sys/types.h>
11 #include <unistd.h>
12 
13 #include <sched.h>
14 
15 #include <cpufreq.h>
16 #include <cpupower.h>
17 
18 #include "config.h"
19 #include "system.h"
20 
21 /**
22  * returns time since epoch in µs
23  *
24  * @retval time
25  **/
26 
27 long long int get_time()
28 {
29 	struct timeval now;
30 
31 	gettimeofday(&now, NULL);
32 
33 	return (long long int)(now.tv_sec * 1000000LL + now.tv_usec);
34 }
35 
36 /**
37  * sets the cpufreq governor
38  *
39  * @param governor cpufreq governor name
40  * @param cpu cpu for which the governor should be set
41  *
42  * @retval 0 on success
43  * @retval -1 when failed
44  **/
45 
46 int set_cpufreq_governor(char *governor, unsigned int cpu)
47 {
48 
49 	dprintf("set %s as cpufreq governor\n", governor);
50 
51 	if (cpupower_is_cpu_online(cpu) != 1) {
52 		perror("cpufreq_cpu_exists");
53 		fprintf(stderr, "error: cpu %u does not exist\n", cpu);
54 		return -1;
55 	}
56 
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);
60 		return -1;
61 	}
62 
63 	return 0;
64 }
65 
66 /**
67  * sets cpu affinity for the process
68  *
69  * @param cpu cpu# to which the affinity should be set
70  *
71  * @retval 0 on success
72  * @retval -1 when setting the affinity failed
73  **/
74 
75 int set_cpu_affinity(unsigned int cpu)
76 {
77 	cpu_set_t cpuset;
78 
79 	CPU_ZERO(&cpuset);
80 	CPU_SET(cpu, &cpuset);
81 
82 	dprintf("set affinity to cpu #%u\n", cpu);
83 
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");
87 		return -1;
88 	}
89 
90 	return 0;
91 }
92 
93 /**
94  * sets the process priority parameter
95  *
96  * @param priority priority value
97  *
98  * @retval 0 on success
99  * @retval -1 when setting the priority failed
100  **/
101 
102 int set_process_priority(int priority)
103 {
104 	struct sched_param param;
105 
106 	dprintf("set scheduler priority to %i\n", priority);
107 
108 	param.sched_priority = priority;
109 
110 	if (sched_setscheduler(0, SCHEDULER, &param) < 0) {
111 		perror("sched_setscheduler");
112 		fprintf(stderr, "warning: unable to set scheduler priority\n");
113 		return -1;
114 	}
115 
116 	return 0;
117 }
118 
119 /**
120  * notifies the user that the benchmark may run some time
121  *
122  * @param config benchmark config values
123  *
124  **/
125 
126 void prepare_user(const struct config *config)
127 {
128 	unsigned long sleep_time = 0;
129 	unsigned long load_time = 0;
130 	unsigned int round;
131 
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);
138 	}
139 
140 	if (config->verbose || config->output != stdout)
141 		printf("approx. test duration: %im\n",
142 		       (int)((sleep_time + load_time) / 60000000));
143 }
144 
145 /**
146  * sets up the cpu affinity and scheduler priority
147  *
148  * @param config benchmark config values
149  *
150  **/
151 
152 void prepare_system(const struct config *config)
153 {
154 	if (config->verbose)
155 		printf("set cpu affinity to cpu #%u\n", config->cpu);
156 
157 	set_cpu_affinity(config->cpu);
158 
159 	switch (config->prio) {
160 	case SCHED_HIGH:
161 		if (config->verbose)
162 			printf("high priority condition requested\n");
163 
164 		set_process_priority(PRIORITY_HIGH);
165 		break;
166 	case SCHED_LOW:
167 		if (config->verbose)
168 			printf("low priority condition requested\n");
169 
170 		set_process_priority(PRIORITY_LOW);
171 		break;
172 	default:
173 		if (config->verbose)
174 			printf("default priority condition requested\n");
175 
176 		set_process_priority(PRIORITY_DEFAULT);
177 	}
178 }
179 
180