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
39long 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
58int 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
87int 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
114int 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
138void 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
164void 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