--- /dev/null
+/* cpufreq-bench CPUFreq microbenchmark
+ *
+ * Copyright (C) 2008 Christian Kornacker <ckornacker@suse.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#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("avarage: %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 avarage 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;
+ }
+}
Code Review / kvmfornfv.git / blobdiff