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 #include <cpupower.h>
30 
31 #include "config.h"
32 #include "system.h"
33 
34 /**
35  * returns time since epoch in µs
36  *
37  * @retval time
38  **/
39 
40 long long int get_time()
41 {
42 	struct timeval now;
43 
44 	gettimeofday(&now, NULL);
45 
46 	return (long long int)(now.tv_sec * 1000000LL + now.tv_usec);
47 }
48 
49 /**
50  * sets the cpufreq governor
51  *
52  * @param governor cpufreq governor name
53  * @param cpu cpu for which the governor should be set
54  *
55  * @retval 0 on success
56  * @retval -1 when failed
57  **/
58 
59 int set_cpufreq_governor(char *governor, unsigned int cpu)
60 {
61 
62 	dprintf("set %s as cpufreq governor\n", governor);
63 
64 	if (cpupower_is_cpu_online(cpu) != 1) {
65 		perror("cpufreq_cpu_exists");
66 		fprintf(stderr, "error: cpu %u does not exist\n", cpu);
67 		return -1;
68 	}
69 
70 	if (cpufreq_modify_policy_governor(cpu, governor) != 0) {
71 		perror("cpufreq_modify_policy_governor");
72 		fprintf(stderr, "error: unable to set %s governor\n", governor);
73 		return -1;
74 	}
75 
76 	return 0;
77 }
78 
79 /**
80  * sets cpu affinity for the process
81  *
82  * @param cpu cpu# to which the affinity should be set
83  *
84  * @retval 0 on success
85  * @retval -1 when setting the affinity failed
86  **/
87 
88 int set_cpu_affinity(unsigned int cpu)
89 {
90 	cpu_set_t cpuset;
91 
92 	CPU_ZERO(&cpuset);
93 	CPU_SET(cpu, &cpuset);
94 
95 	dprintf("set affinity to cpu #%u\n", cpu);
96 
97 	if (sched_setaffinity(getpid(), sizeof(cpu_set_t), &cpuset) < 0) {
98 		perror("sched_setaffinity");
99 		fprintf(stderr, "warning: unable to set cpu affinity\n");
100 		return -1;
101 	}
102 
103 	return 0;
104 }
105 
106 /**
107  * sets the process priority parameter
108  *
109  * @param priority priority value
110  *
111  * @retval 0 on success
112  * @retval -1 when setting the priority failed
113  **/
114 
115 int set_process_priority(int priority)
116 {
117 	struct sched_param param;
118 
119 	dprintf("set scheduler priority to %i\n", priority);
120 
121 	param.sched_priority = priority;
122 
123 	if (sched_setscheduler(0, SCHEDULER, &param) < 0) {
124 		perror("sched_setscheduler");
125 		fprintf(stderr, "warning: unable to set scheduler priority\n");
126 		return -1;
127 	}
128 
129 	return 0;
130 }
131 
132 /**
133  * notifies the user that the benchmark may run some time
134  *
135  * @param config benchmark config values
136  *
137  **/
138 
139 void prepare_user(const struct config *config)
140 {
141 	unsigned long sleep_time = 0;
142 	unsigned long load_time = 0;
143 	unsigned int round;
144 
145 	for (round = 0; round < config->rounds; round++) {
146 		sleep_time +=  2 * config->cycles *
147 			(config->sleep + config->sleep_step * round);
148 		load_time += 2 * config->cycles *
149 			(config->load + config->load_step * round) +
150 			(config->load + config->load_step * round * 4);
151 	}
152 
153 	if (config->verbose || config->output != stdout)
154 		printf("approx. test duration: %im\n",
155 		       (int)((sleep_time + load_time) / 60000000));
156 }
157 
158 /**
159  * sets up the cpu affinity and scheduler priority
160  *
161  * @param config benchmark config values
162  *
163  **/
164 
165 void prepare_system(const struct config *config)
166 {
167 	if (config->verbose)
168 		printf("set cpu affinity to cpu #%u\n", config->cpu);
169 
170 	set_cpu_affinity(config->cpu);
171 
172 	switch (config->prio) {
173 	case SCHED_HIGH:
174 		if (config->verbose)
175 			printf("high priority condition requested\n");
176 
177 		set_process_priority(PRIORITY_HIGH);
178 		break;
179 	case SCHED_LOW:
180 		if (config->verbose)
181 			printf("low priority condition requested\n");
182 
183 		set_process_priority(PRIORITY_LOW);
184 		break;
185 	default:
186 		if (config->verbose)
187 			printf("default priority condition requested\n");
188 
189 		set_process_priority(PRIORITY_DEFAULT);
190 	}
191 }
192 
193