cpupowerutils - cpufrequtils extended with quite some features

CPU power consumption vs performance tuning is no longer
limited to CPU frequency switching anymore: deep sleep states,
traditional dynamic frequency scaling and hidden turbo/boost
frequencies are tied close together and depend on each other.
The first two exist on different architectures like PPC, Itanium and
ARM, the latter (so far) only on X86. On X86 the APU (CPU+GPU) will
only run most efficiently if CPU and GPU has proper power management
in place.

Users and Developers want to have *one* tool to get an overview what
their system supports and to monitor and debug CPU power management
in detail. The tool should compile and work on as many architectures
as possible.

Once this tool stabilizes a bit, it is intended to replace the
Intel-specific tools in tools/power/x86

Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>

1 files changed, 184 insertions, 0 deletions

diff --git a/tools/power/cpupower/bench/benchmark.c b/tools/power/cpupower/bench/benchmark.c
new file mode 100644
index 00000000000..f538633b8b4
--- /dev/null
+++ b/tools/power/cpupower/bench/benchmark.c
@@ -0,0 +1,184 @@
+/*  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;
+	}
+}
+