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 <unistd.h>
22 #include <math.h>
23 
24 #include "config.h"
25 #include "system.h"
26 #include "benchmark.h"
27 
28 /* Print out progress if we log into a file */
29 #define show_progress(total_time, progress_time)	\
30 if (config->output != stdout) {				\
31 	fprintf(stdout, "Progress: %02lu %%\r",		\
32 		(progress_time * 100) / total_time);	\
33 	fflush(stdout);					\
34 }
35 
36 /**
37  * compute how many rounds of calculation we should do
38  * to get the given load time
39  *
40  * @param load aimed load time in µs
41  *
42  * @retval rounds of calculation
43  **/
44 
45 unsigned int calculate_timespace(long load, struct config *config)
46 {
47 	int i;
48 	long long now, then;
49 	unsigned int estimated = GAUGECOUNT;
50 	unsigned int rounds = 0;
51 	unsigned int timed = 0;
52 
53 	if (config->verbose)
54 		printf("calibrating load of %lius, please wait...\n", load);
55 
56 	/* get the initial calculation time for a specific number of rounds */
57 	now = get_time();
58 	ROUNDS(estimated);
59 	then = get_time();
60 
61 	timed = (unsigned int)(then - now);
62 
63 	/* approximation of the wanted load time by comparing with the
64 	 * initial calculation time */
65 	for (i = 0; i < 4; i++) {
66 		rounds = (unsigned int)(load * estimated / timed);
67 		dprintf("calibrating with %u rounds\n", rounds);
68 		now = get_time();
69 		ROUNDS(rounds);
70 		then = get_time();
71 
72 		timed = (unsigned int)(then - now);
73 		estimated = rounds;
74 	}
75 	if (config->verbose)
76 		printf("calibration done\n");
77 
78 	return estimated;
79 }
80 
81 /**
82  * benchmark
83  * generates a specific sleep an load time with the performance
84  * governor and compares the used time for same calculations done
85  * with the configured powersave governor
86  *
87  * @param config config values for the benchmark
88  *
89  **/
90 
91 void start_benchmark(struct config *config)
92 {
93 	unsigned int _round, cycle;
94 	long long now, then;
95 	long sleep_time = 0, load_time = 0;
96 	long performance_time = 0, powersave_time = 0;
97 	unsigned int calculations;
98 	unsigned long total_time = 0, progress_time = 0;
99 
100 	sleep_time = config->sleep;
101 	load_time = config->load;
102 
103 	/* For the progress bar */
104 	for (_round = 1; _round <= config->rounds; _round++)
105 		total_time += _round * (config->sleep + config->load);
106 	total_time *= 2; /* powersave and performance cycles */
107 
108 	for (_round = 0; _round < config->rounds; _round++) {
109 		performance_time = 0LL;
110 		powersave_time = 0LL;
111 
112 		show_progress(total_time, progress_time);
113 
114 		/* set the cpufreq governor to "performance" which disables
115 		 * P-State switching. */
116 		if (set_cpufreq_governor("performance", config->cpu) != 0)
117 			return;
118 
119 		/* calibrate the calculation time. the resulting calculation
120 		 * _rounds should produce a load which matches the configured
121 		 * load time */
122 		calculations = calculate_timespace(load_time, config);
123 
124 		if (config->verbose)
125 			printf("_round %i: doing %u cycles with %u calculations"
126 			       " for %lius\n", _round + 1, config->cycles,
127 			       calculations, load_time);
128 
129 		fprintf(config->output, "%u %li %li ",
130 			_round, load_time, sleep_time);
131 
132 		if (config->verbose)
133 			printf("avarage: %lius, rps:%li\n",
134 				load_time / calculations,
135 				1000000 * calculations / load_time);
136 
137 		/* do some sleep/load cycles with the performance governor */
138 		for (cycle = 0; cycle < config->cycles; cycle++) {
139 			now = get_time();
140 			usleep(sleep_time);
141 			ROUNDS(calculations);
142 			then = get_time();
143 			performance_time += then - now - sleep_time;
144 			if (config->verbose)
145 				printf("performance cycle took %lius, "
146 					"sleep: %lius, "
147 					"load: %lius, rounds: %u\n",
148 					(long)(then - now), sleep_time,
149 					load_time, calculations);
150 		}
151 		fprintf(config->output, "%li ",
152 			performance_time / config->cycles);
153 
154 		progress_time += sleep_time + load_time;
155 		show_progress(total_time, progress_time);
156 
157 		/* set the powersave governor which activates P-State switching
158 		 * again */
159 		if (set_cpufreq_governor(config->governor, config->cpu) != 0)
160 			return;
161 
162 		/* again, do some sleep/load cycles with the
163 		 * powersave governor */
164 		for (cycle = 0; cycle < config->cycles; cycle++) {
165 			now = get_time();
166 			usleep(sleep_time);
167 			ROUNDS(calculations);
168 			then = get_time();
169 			powersave_time += then - now - sleep_time;
170 			if (config->verbose)
171 				printf("powersave cycle took %lius, "
172 					"sleep: %lius, "
173 					"load: %lius, rounds: %u\n",
174 					(long)(then - now), sleep_time,
175 					load_time, calculations);
176 		}
177 
178 		progress_time += sleep_time + load_time;
179 
180 		/* compare the avarage sleep/load cycles  */
181 		fprintf(config->output, "%li ",
182 			powersave_time / config->cycles);
183 		fprintf(config->output, "%.3f\n",
184 			performance_time * 100.0 / powersave_time);
185 		fflush(config->output);
186 
187 		if (config->verbose)
188 			printf("performance is at %.2f%%\n",
189 				performance_time * 100.0 / powersave_time);
190 
191 		sleep_time += config->sleep_step;
192 		load_time += config->load_step;
193 	}
194 }
195