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// SPDX-License-Identifier: GPL-2.0-or-later
/* cpufreq-bench CPUFreq microbenchmark
*
* Copyright (C) 2008 Christian Kornacker <ckornacker@suse.de>
*/
#include <stdio.h>
#include <unistd.h>
#include <math.h>
#include "config.h"
#include "system.h"
#include "benchmark.h"
/* Print out progress if we log into a file */
#define show_progress(total_time, progress_time) \
if (config->output != stdout) { \
fprintf(stdout, "Progress: %02lu %%\r", \
(progress_time * 100) / total_time); \
fflush(stdout); \
}
/**
* compute how many rounds of calculation we should do
* to get the given load time
*
* @param load aimed load time in µs
*
* @retval rounds of calculation
**/
unsigned int calculate_timespace(long load, struct config *config)
{
int i;
long long now, then;
unsigned int estimated = GAUGECOUNT;
unsigned int rounds = 0;
unsigned int timed = 0;
if (config->verbose)
printf("calibrating load of %lius, please wait...\n", load);
/* get the initial calculation time for a specific number of rounds */
now = get_time();
ROUNDS(estimated);
then = get_time();
timed = (unsigned int)(then - now);
/* approximation of the wanted load time by comparing with the
* initial calculation time */
for (i = 0; i < 4; i++) {
rounds = (unsigned int)(load * estimated / timed);
dprintf("calibrating with %u rounds\n", rounds);
now = get_time();
ROUNDS(rounds);
then = get_time();
timed = (unsigned int)(then - now);
estimated = rounds;
}
if (config->verbose)
printf("calibration done\n");
return estimated;
}
/**
* benchmark
* generates a specific sleep an load time with the performance
* governor and compares the used time for same calculations done
* with the configured powersave governor
*
* @param config config values for the benchmark
*
**/
void start_benchmark(struct config *config)
{
unsigned int _round, cycle;
long long now, then;
long sleep_time = 0, load_time = 0;
long performance_time = 0, powersave_time = 0;
unsigned int calculations;
unsigned long total_time = 0, progress_time = 0;
sleep_time = config->sleep;
load_time = config->load;
/* For the progress bar */
for (_round = 1; _round <= config->rounds; _round++)
total_time += _round * (config->sleep + config->load);
total_time *= 2; /* powersave and performance cycles */
for (_round = 0; _round < config->rounds; _round++) {
performance_time = 0LL;
powersave_time = 0LL;
show_progress(total_time, progress_time);
/* set the cpufreq governor to "performance" which disables
* P-State switching. */
if (set_cpufreq_governor("performance", config->cpu) != 0)
return;
/* calibrate the calculation time. the resulting calculation
* _rounds should produce a load which matches the configured
* load time */
calculations = calculate_timespace(load_time, config);
if (config->verbose)
printf("_round %i: doing %u cycles with %u calculations"
" for %lius\n", _round + 1, config->cycles,
calculations, load_time);
fprintf(config->output, "%u %li %li ",
_round, load_time, sleep_time);
if (config->verbose)
printf("average: %lius, rps:%li\n",
load_time / calculations,
1000000 * calculations / load_time);
/* do some sleep/load cycles with the performance governor */
for (cycle = 0; cycle < config->cycles; cycle++) {
now = get_time();
usleep(sleep_time);
ROUNDS(calculations);
then = get_time();
performance_time += then - now - sleep_time;
if (config->verbose)
printf("performance cycle took %lius, "
"sleep: %lius, "
"load: %lius, rounds: %u\n",
(long)(then - now), sleep_time,
load_time, calculations);
}
fprintf(config->output, "%li ",
performance_time / config->cycles);
progress_time += sleep_time + load_time;
show_progress(total_time, progress_time);
/* set the powersave governor which activates P-State switching
* again */
if (set_cpufreq_governor(config->governor, config->cpu) != 0)
return;
/* again, do some sleep/load cycles with the
* powersave governor */
for (cycle = 0; cycle < config->cycles; cycle++) {
now = get_time();
usleep(sleep_time);
ROUNDS(calculations);
then = get_time();
powersave_time += then - now - sleep_time;
if (config->verbose)
printf("powersave cycle took %lius, "
"sleep: %lius, "
"load: %lius, rounds: %u\n",
(long)(then - now), sleep_time,
load_time, calculations);
}
progress_time += sleep_time + load_time;
/* compare the average sleep/load cycles */
fprintf(config->output, "%li ",
powersave_time / config->cycles);
fprintf(config->output, "%.3f\n",
performance_time * 100.0 / powersave_time);
fflush(config->output);
if (config->verbose)
printf("performance is at %.2f%%\n",
performance_time * 100.0 / powersave_time);
sleep_time += config->sleep_step;
load_time += config->load_step;
}
}
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