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 
192