Introduce cpufreq micro benchmark

What is this benchmark for:
  - Identify worst case performance loss when doing dynamic frequency
    scaling using Linux kernel governors
  - Identify average reaction time of a governor to CPU load changes
  - (Stress) Testing whether a cpufreq low level driver or governor works
    as expected
  - Identify cpufreq related performance regressions between kernels
  - Possibly Real time priority testing? -> what happens if there are
    processes with a higher prio than the governor's kernel thread
  - ...

What this benchmark does *not* cover:
  - Power saving related regressions (In fact as better the performance
    throughput is, the worse the power savings will be, but the first should
    mostly count more...)
  - Real world (workloads)

Details how to use it can be found in the readme.
The benchmark got written by Christian Kornacker <ckornacker@suse.de>
and is published under the GNU General Public License.
(compare with copyright remarks inside the code).

cpufrequtils Makefile adjustments and some minor compile warning cleanups
came from:

Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>

12 files changed, 1007 insertions, 2 deletions

diff --git a/Makefile b/Makefile
index c46be5b..bfea0fb 100644
--- a/Makefile
+++ b/Makefile
@@ -33,6 +33,9 @@ V ?=		false
 # Requires gettext.
 NLS ?=		true
 
+# cpufreq-bench benchmarking tool
+CPUFRQ_BENCH ?= true
+
 # Use the sysfs-based interface which is included in all 2.6 kernels
 # built with cpufreq support
 SYSFS ?=	true
@@ -62,10 +65,13 @@ LANGUAGES = 			de fr it cs pt
 # added in front of any of them
 
 bindir ?=	/usr/bin
+sbindir ?=	/usr/sbin
 mandir ?=	/usr/man
 includedir ?=	/usr/include
 libdir ?=	/usr/lib
 localedir ?=	/usr/share/locale
+docdir ?=       /usr/share/doc/packages/cpufrequtils
+confdir ?=      /etc/
 
 # Toolchain: what tools do we use, and what options do they need:
 
@@ -142,6 +148,10 @@ ifeq ($(strip $(NLS)),true)
 	COMPILE_NLS += update-gmo
 endif
 
+ifeq ($(strip $(CPUFRQ_BENCH)),true)
+	INSTALL_BENCH += install-bench
+	COMPILE_BENCH += compile-bench
+endif
 
 CFLAGS += $(WARNINGS) -I$(GCCINCDIR)
 
@@ -169,7 +179,7 @@ endif
 
 # the actual make rules
 
-all: ccdv libcpufreq utils $(COMPILE_NLS)
+all: ccdv libcpufreq utils $(COMPILE_NLS) $(COMPILE_BENCH)
 
 ccdv: build/ccdv
 build/ccdv: build/ccdv.c
@@ -215,6 +225,9 @@ update-gmo: po/$(PACKAGE).pot
 		msgfmt --statistics -o po/$$HLANG.gmo po/$$HLANG.po; \
 	done;
 
+compile-bench: libcpufreq
+	@V=$(V) make -C bench
+
 clean:
 	-find . \( -not -type d \) -and \( -name '*~' -o -name '*.[oas]' -o -name '*.l[oas]' \) -type f -print \
 	 | xargs rm -f
@@ -223,6 +236,7 @@ clean:
 	-rm -f cpufreq-info cpufreq-set
 	-rm -f build/ccdv
 	-rm -rf po/*.gmo po/*.pot
+	make -C bench clean
 
 
 install-lib:
@@ -247,7 +261,11 @@ install-gmo:
 		$(INSTALL_DATA) -D po/$$HLANG.gmo $(DESTDIR)${localedir}/$$HLANG/LC_MESSAGES/cpufrequtils.mo; \
 	done;
 
-install: install-lib install-tools install-man $(INSTALL_NLS)
+install-bench:
+	@#DESTDIR must be set from outside to survive
+	@sbindir=$(sbindir) docdir=$(docdir) confdir=$(confdir) make -C bench install
+       
+install: install-lib install-tools install-man $(INSTALL_NLS) $(INSTALL_BENCH)
 
 uninstall:
 	- rm -f $(DESTDIR)${libdir}/libcpufreq.*
diff --git a/bench/Makefile b/bench/Makefile
new file mode 100644
index 0000000..327c4e6
--- /dev/null
+++ b/bench/Makefile
@@ -0,0 +1,27 @@
+LIBS = -L../.libs/ -lm -lcpufreq
+
+OBJS = main.o parse.o system.o benchmark.o
+CFLAGS += -D_GNU_SOURCE
+
+ifeq ($(strip $(V)),false)
+	CC=@../build/ccdv gcc
+else
+	CC=gcc
+endif
+
+cpufreq-bench: $(OBJS)
+	$(CC) -o $@ $(CFLAGS) $(OBJS) $(LIBS)
+
+all: cpufreq-bench
+
+install:
+	mkdir -p $(DESTDIR)/$(sbindir)
+	mkdir -p $(DESTDIR)/$(docdir)
+	mkdir -p $(DESTDIR)/$(confdir)
+	install -m 755 cpufreq-bench $(DESTDIR)/$(sbindir)/cpufreq-bench
+	install -m 644 README $(DESTDIR)/$(docdir)/README
+	install -m 644 example.cfg $(DESTDIR)/$(confdir)/cpufreq-bench.conf
+
+clean:
+	rm -f *.o
+	rm -f cpufreq-bench
diff --git a/bench/README b/bench/README
new file mode 100644
index 0000000..4f6a225
--- /dev/null
+++ b/bench/README
@@ -0,0 +1,49 @@
+This is cpufreq-bench, a microbenchmark for the cpufreq framework.
+
+description:
+cpufreq-bench helps to test the condition of a given cpufreq governor.
+For that purpose, it compares the performance governor to a configured
+powersave module.
+
+The functional principle is quite easy: we generate a load for a specific
+time with the performance governor. The load is generated with some rounds
+of calculation. Now, we idle for some time to let the CPU change to a lower
+frequency. Then, We take that amount of rounds and do another test with
+the powersave governor. But now, we don’t generate load for a specific time
+but rather generate load with the amount of calculations we’ve got.
+The resulting time is compared to the time we spent for the initial
+performance calculation.
+The powersave cycle should take 1-40% longer than the performance cycle due
+to the time the CPU needs to change to a higher frequency.
+nr. of calculations
+
+^
+|__________________ _ _ _ _ _
+|   performance    | powersave|
+|                  |          |
+|                  |          |
+|-----------------------------------------------> time
+
+To get a more precise value, this sleep/load cycle is done several times.
+We use the average values for the comparison.
+After each round, a specific time is added to the load and sleep time to see
+how good the sleep/load switch behaves with different timeframes.
+
+
+usage:
+-l, --load=<long int>           initial load time in us
+-s, --sleep=<long int>          initial sleep time in us
+-x, --load-step=<long int>      time to be added to load time, in us
+-y, --sleep-step=<long int>     time to be added to sleep time, in us
+-c, --cpu=<unsigned int>        CPU Number to use, starting at 0
+-p, --prio=<priority>           scheduler priority, HIGH, LOW or DEFAULT
+-g, --governor=<governor>       cpufreq governor to test
+-n, --cycles=<int>              load/sleep cycles to get an avarage value to compare
+-r, --rounds<int>               load/sleep rounds
+-f, --file=<configfile>         config file to use
+-o, --output=<dir>              output dir, must exist
+-v, --verbose                   verbose output on/off
+
+Due to the high priority, the application my not be responsible for some time.
+After the benchmark, the logfile is saved in OUTPUTDIR/benchmark_TIMESTAMP.log
+
diff --git a/bench/benchmark.c b/bench/benchmark.c
new file mode 100644
index 0000000..d9c1d47
--- /dev/null
+++ b/bench/benchmark.c
@@ -0,0 +1,160 @@
+/*  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"
+
+/**
+ * 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)
+{
+	int i;
+	long long now, then;
+	unsigned int estimated = GAUGECOUNT;
+	unsigned int rounds = 0;
+	unsigned int timed = 0;
+
+	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;
+	}
+
+	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;
+
+	sleep_time = config->sleep;
+	load_time = config->load;
+
+	for (_round=0; _round < config->rounds; _round++) {
+		performance_time = 0LL;
+		powersave_time = 0LL;
+
+		/* set the cpufreq governor to "performance" which disables
+		 * P-State switching. */
+		if (set_cpufreq_governor("performance", config->cpu) != 0)
+			return;
+
+		printf("_round %i: doing %u cycles with %u calculations for %lius\n",
+			_round + 1, config->cycles, calculations, load_time);
+
+		/* calibrate the calculation time. the resulting calculation
+		 * _rounds should produce a load which matches the configured
+		 * load time */
+		calculations = calculate_timespace(load_time);
+
+		fprintf(config->output, "%li %li %li %u ",
+					load_time, sleep_time, load_time / calculations, calculations);
+
+		if (config->verbose) {
+			printf("avarage: %lius, rps:%li\n", load_time / calculations, 1000000 * calculations / load_time);
+		}
+
+		/* do some sleep/load cycles and determine the avarege time we need
+		 * for one cycle */
+		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);
+
+		/* 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);
+		}
+
+		/* 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);
+
+		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;
+	}
+}
+
diff --git a/bench/benchmark.h b/bench/benchmark.h
new file mode 100644
index 0000000..9def4fd
--- /dev/null
+++ b/bench/benchmark.h
@@ -0,0 +1,28 @@
+/*  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.
+ */
+
+/* load loop, this schould take about 1 to 2ms to complete */
+#define ROUNDS(x) {unsigned int rcnt;			       \
+		for (rcnt = 0; rcnt< x*1000; rcnt++) { \
+			(void)(((int)(pow(rcnt, rcnt) * sqrt(rcnt*7230970)) ^ 7230716) ^ (int)atan2(rcnt, rcnt)); \
+		}}							\
+
+
+unsigned int calculate_timespace(long load);
+void start_benchmark(struct config *config);
diff --git a/bench/config.h b/bench/config.h
new file mode 100644
index 0000000..9690f1b
--- /dev/null
+++ b/bench/config.h
@@ -0,0 +1,36 @@
+/*  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.
+ */
+
+/* initial loop count for the load calibration */
+#define GAUGECOUNT	1500
+
+/* default scheduling policy SCHED_OTHER */
+#define SCHEDULER	SCHED_OTHER
+
+#define PRIORITY_DEFAULT 0
+#define PRIORITY_HIGH	 sched_get_priority_max(SCHEDULER)
+#define PRIORITY_LOW	 sched_get_priority_min(SCHEDULER)
+
+/* enable further debug messages */
+#ifdef DEBUG
+#define dprintf printf
+#else
+#define dprintf( ... ) while(0) { }
+#endif
+
diff --git a/bench/example.cfg b/bench/example.cfg
new file mode 100644
index 0000000..09d2765
--- /dev/null
+++ b/bench/example.cfg
@@ -0,0 +1,11 @@
+sleep = 25000
+load = 25000
+cpu = 0 
+priority = LOW 
+output = /tmp
+sleep_step = 25000
+load_step = 25000
+cycles = 10
+rounds = 60
+#verbose = 0
+governor = ondemand
diff --git a/bench/main.c b/bench/main.c
new file mode 100644
index 0000000..1ff1525
--- /dev/null
+++ b/bench/main.c
@@ -0,0 +1,203 @@
+/*  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 <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <getopt.h>
+#include <errno.h>
+
+#include "config.h"
+#include "system.h"
+#include "benchmark.h"
+
+static struct option long_options[] =
+{
+	{"output",	1,	0,	'o'},
+	{"sleep",	1,	0,	's'},
+	{"load",	1,	0,	'l'},
+	{"verbose",	0,	0,	'v'},
+	{"cpu",		1,	0,	'c'},
+	{"governor",	1,	0,	'g'},
+	{"prio",	1,	0,	'p'},
+	{"file",	1,	0,	'f'},
+	{"cycles",	1,	0,	'n'},
+	{"rounds",	1,	0,	'r'},
+	{"load-step",	1,	0,	'x'},
+	{"sleep-step",	1,	0,	'y'},
+	{"help",	0,	0,	'h'},
+	{0, 0, 0, 0}
+};
+
+/*******************************************************************
+ usage
+*******************************************************************/
+
+void usage() 
+{
+	printf("usage: ./bench\n");
+	printf("Options:\n");
+	printf(" -l, --load=<long int>\t\tinitial load time in us\n");
+	printf(" -s, --sleep=<long int>\t\tinitial sleep time in us\n");
+	printf(" -x, --load-step=<long int>\ttime to be added to load time, in us\n");
+	printf(" -y, --sleep-step=<long int>\ttime to be added to sleep time, in us\n");
+	printf(" -c, --cpu=<cpu #>\t\t\tCPU Nr. to use, starting at 0\n");
+	printf(" -p, --prio=<priority>\t\t\tscheduler priority, HIGH, LOW or DEFAULT\n");
+	printf(" -g, --governor=<governor>\t\tcpufreq governor to test\n");
+	printf(" -n, --cycles=<int>\t\t\tload/sleep cycles\n");
+	printf(" -r, --rounds<int>\t\t\tload/sleep rounds\n");
+	printf(" -f, --file=<configfile>\t\tconfig file to use\n");
+	printf(" -o, --output=<dir>\t\t\toutput path. Filename will be OUTPUTPATH/benchmark_TIMESTAMP.log\n");
+	printf(" -v, --verbose\t\t\t\tverbose output on/off\n");
+	printf(" -h, --help\t\t\t\tPrint this help screen\n");
+	exit (1);
+}
+
+/*******************************************************************
+ main
+*******************************************************************/
+
+int main(int argc, char **argv)
+{
+	int c;
+	int option_index = 0;
+	struct config *config = NULL;
+
+	if (argc == 1)
+		usage();
+
+	config = prepare_default_config();
+
+	if (config == NULL)
+		return EXIT_FAILURE;
+
+	while (1) {
+		c = getopt_long (argc, argv, "hg:o:s:l:vc:p:f:n:r:x:y:",
+				long_options, &option_index);
+		if (c == -1)
+			break;
+
+		switch (c) {
+		case 'o':
+			if (config->output != NULL)
+				fclose(config->output);
+
+			config->output = prepare_output(optarg);
+
+			if (config->output == NULL)
+				return EXIT_FAILURE;
+
+			dprintf("user output path -> %s\n", optarg);
+			break;
+		case 's':
+			sscanf(optarg, "%li", &config->sleep);
+			dprintf("user sleep time -> %s\n", optarg);
+			break;
+		case 'l':
+			sscanf(optarg, "%li", &config->load);
+			dprintf("user load time -> %s\n", optarg);
+			break;
+		case 'c':
+			sscanf(optarg, "%u", &config->cpu);
+			dprintf("user cpu -> %s\n", optarg);
+			break;
+		case 'g':
+			strncpy(config->governor, optarg, 14);
+			dprintf("user governor -> %s\n", optarg);
+			break;
+		case 'p':
+			if (string_to_prio(optarg) != SCHED_ERR) {
+				config->prio = string_to_prio(optarg);
+				dprintf("user prio -> %s\n", optarg);
+			} else {
+				if (config != NULL) {
+					if (config->output != NULL)
+						fclose(config->output);
+					free(config);
+				}
+				usage();
+			}
+			break;
+		case 'n':
+			sscanf(optarg, "%u", &config->cycles);
+			dprintf("user cycles -> %s\n", optarg);
+			break;
+		case 'r':
+			sscanf(optarg, "%u", &config->rounds);
+			dprintf("user rounds -> %s\n", optarg);
+			break;
+		case 'x':
+			sscanf(optarg, "%li", &config->load_step);
+			dprintf("user load_step -> %s\n", optarg);
+			break;
+		case 'y':
+			sscanf(optarg, "%li", &config->sleep_step);
+			dprintf("user sleep_step -> %s\n", optarg);
+			break;
+		case 'f':
+			config = prepare_config(optarg);
+			if (config == NULL)
+				return EXIT_FAILURE;
+			break;
+		case 'v':
+			config->verbose = 1;
+			dprintf("verbose output enabled\n");
+			break;
+		case 'h':
+		case '?':
+		default:
+			if (config != NULL) {
+				if (config->output != NULL)
+					fclose(config->output);
+				free(config);
+			}
+			usage();
+		}
+	}
+
+	printf("starting benchmark with parameters:\n");
+	printf("config:\n\t"
+		"sleep=%li\n\t"
+		"load=%li\n\t"
+		"sleep_step=%li\n\t"
+		"load_step=%li\n\t"
+		"cpu=%u\n\t"
+		"cycles=%u\n\t"
+		"rounds=%u\n\t"
+		"governor=%s\n\n",
+		config->sleep,
+		config->load,
+		config->sleep_step,
+		config->load_step,
+		config->cpu,
+		config->cycles,
+		config->rounds,
+		config->governor);
+
+	prepare_user(config);
+	prepare_system(config);
+	start_benchmark(config);
+
+	fclose (config->output);
+	free (config);
+
+	return EXIT_SUCCESS;
+}
+
diff --git a/bench/parse.c b/bench/parse.c
new file mode 100644
index 0000000..2b26279
--- /dev/null
+++ b/bench/parse.c
@@ -0,0 +1,201 @@
+/*  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 <stdlib.h>
+#include <stdarg.h>
+#include <string.h>
+#include <time.h>
+#include <sys/utsname.h>
+
+#include "parse.h"
+#include "config.h"
+
+/**
+ * converts priority string to priority
+ *
+ * @param str string that represents a scheduler priority
+ *
+ * @retval priority
+ * @retval SCHED_ERR when the priority doesn't exit
+ **/
+
+enum sched_prio string_to_prio(const char *str)
+{
+	if (strncasecmp("high", str, strlen(str)) == 0)
+		return  SCHED_HIGH;
+	else if (strncasecmp("default", str, strlen(str)) == 0)
+		return SCHED_DEFAULT;
+	else if (strncasecmp("low", str, strlen(str)) == 0)
+		return SCHED_LOW;
+	else
+		return SCHED_ERR;
+}
+
+/**
+ * create and open logfile
+ *
+ * @param dir directory in which the logfile should be created
+ *
+ * @retval logfile on success
+ * @retval NULL when the file can't be created
+ **/
+
+FILE *prepare_output(const char *dir)
+{
+	FILE *output = NULL;
+	int len;
+	char *filename;
+	struct utsname sysdata;
+	
+	len = strlen(dir) + 30;
+	filename = malloc(sizeof(char) * len);
+
+	if (uname(&sysdata) == 0) {
+		len += strlen(sysdata.nodename) + strlen(sysdata.release);
+		filename = realloc(filename, sizeof(char) * len);
+
+		if(filename == NULL) {
+			perror("realloc");
+			return NULL;
+		}
+
+		snprintf(filename, len - 1, "%s/benchmark_%s_%s_%li.log", 
+			dir, sysdata.nodename, sysdata.release, time(NULL));
+	} else {
+		snprintf(filename, len -1, "%s/benchmark_%li.log", dir, time(NULL));
+	}
+
+	dprintf("logilename: %s\n", filename);
+
+	if ((output = fopen(filename, "w+")) == NULL) {
+		perror("fopen");
+		fprintf(stderr, "error: unable to open logfile\n");
+	}
+
+	free(filename);
+	fprintf(output, "#load sleep avarage rounds performance powersave percentage\n");
+	return output;
+}
+
+/**
+ * returns the default config
+ *
+ * @retval default config on success
+ * @retval NULL when the output file can't be created
+ **/
+
+struct config *prepare_default_config()
+{
+	struct config *config = malloc(sizeof(struct config));
+
+	dprintf("loading defaults\n");
+
+	config->sleep = 500000;
+	config->load = 500000;
+	config->sleep_step = 500000;
+	config->load_step = 500000;
+	config->cycles = 5;
+	config->rounds = 50;
+	config->cpu = 0;	
+	config->prio = SCHED_HIGH;
+	config->verbose = 0;
+	strncpy(config->governor, "ondemand", 8);
+
+	if ((config->output = prepare_output("/tmp")) == NULL) {
+		free(config);
+		return NULL;
+	}
+	
+	return config;
+}
+
+/**
+ * parses config file and returns the config to the caller
+ *
+ * @param path config file name
+ *
+ * @retval parsed benchmark config
+ **/
+
+struct config *prepare_config(const char *path)
+{
+	size_t len = 0;
+	char *opt, *val, *line = NULL;
+	FILE *configfile = fopen(path, "r");
+	struct config *config = malloc(sizeof(struct config));
+
+	if (configfile == NULL) {
+		perror("fopen");
+                fprintf(stderr, "error: unable to read configfile\n");
+		free(config);
+		return NULL;
+	}
+
+	while (getline(&line, &len, configfile) != -1)
+	{
+		if (line[0] == '#' || line[0] == ' ')
+			continue;
+
+		sscanf(line, "%as = %as", &opt, &val);
+
+		dprintf("parsing: %s -> %s\n", opt, val);
+
+		if (strncmp("sleep", opt, strlen(opt)) == 0)
+			sscanf(val, "%li", &config->sleep);
+
+		else if (strncmp("load", opt, strlen(opt)) == 0) 
+			sscanf(val, "%li", &config->load);
+
+		else if (strncmp("load_step", opt, strlen(opt)) == 0) 
+			sscanf(val, "%li", &config->load_step);
+
+		else if (strncmp("sleep_step", opt, strlen(opt)) == 0) 
+			sscanf(val, "%li", &config->sleep_step);
+
+		else if (strncmp("cycles", opt, strlen(opt)) == 0) 
+			sscanf(val, "%u", &config->cycles);
+
+		else if (strncmp("rounds", opt, strlen(opt)) == 0) 
+			sscanf(val, "%u", &config->rounds);
+
+		else if (strncmp("verbose", opt, strlen(opt)) == 0) 
+			sscanf(val, "%u", &config->verbose);
+
+		else if (strncmp("output", opt, strlen(opt)) == 0) 
+			config->output = prepare_output(val); 
+
+		else if (strncmp("cpu", opt, strlen(opt)) == 0) 
+			sscanf(val, "%u", &config->cpu);
+
+		else if (strncmp("governor", opt, 14) == 0) 
+			strncpy(config->governor, val, 14);
+
+		else if (strncmp("priority", opt, strlen(opt)) == 0) {
+			if (string_to_prio(val) != SCHED_ERR) 
+				config->prio = string_to_prio(val);
+		}
+	}
+
+	free(line);
+	free(opt);
+	free(val);
+
+	return config;
+}
diff --git a/bench/parse.h b/bench/parse.h
new file mode 100644
index 0000000..45ec3be
--- /dev/null
+++ b/bench/parse.h
@@ -0,0 +1,48 @@
+/*  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.
+ */
+
+/* struct that holds the required config parameters */
+struct config
+{
+	long sleep;		/* sleep time in µs */
+	long load;		/* load time in µs */
+	long sleep_step;	/* time value which changes the
+				 * sleep time after every round in µs */
+	long load_step;		/* time value which changes the
+				 * load time after every round in µs */
+	unsigned int cycles;	/* calculation cycles with the same sleep/load time */
+	unsigned int rounds;	/* calculation rounds with iterated sleep/load time */
+	unsigned int cpu;	/* cpu for which the affinity is set */
+	char governor[15];	/* cpufreq governor */
+	enum sched_prio		/* possible scheduler priorities */
+	{
+		SCHED_ERR=-1,SCHED_HIGH, SCHED_DEFAULT, SCHED_LOW
+	} prio;
+
+	unsigned int verbose;	/* verbose output */
+	FILE *output;		/* logfile */
+};
+
+enum sched_prio string_to_prio(const char *str);
+
+FILE *prepare_output(const char *dir);
+
+struct config *prepare_config(const char *path);
+struct config *prepare_default_config();
+
diff --git a/bench/system.c b/bench/system.c
new file mode 100644
index 0000000..d089057
--- /dev/null
+++ b/bench/system.c
@@ -0,0 +1,195 @@
+/*  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 <time.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <sched.h>
+
+#include <cpufreq.h>
+
+#include "config.h"
+#include "system.h"
+
+/**
+ * returns time since epoch in µs
+ *
+ * @retval time
+ **/
+
+long long int get_time()
+{
+	struct timeval now;
+
+	gettimeofday(&now, NULL);
+
+	return (long long int)(now.tv_sec * 1000000LL + now.tv_usec);
+}
+
+/**
+ * sets the cpufreq governor
+ *
+ * @param governor cpufreq governor name
+ * @param cpu cpu for which the governor should be set
+ *
+ * @retval 0 on success
+ * @retval -1 when failed
+ **/
+
+int set_cpufreq_governor(char *governor, unsigned int cpu)
+{
+
+	dprintf("set %s as cpufreq governor\n", governor);
+
+	if (cpufreq_cpu_exists(cpu) != 0) {
+		perror("cpufreq_cpu_exists");
+		fprintf(stderr, "error: cpu %u does not exist\n", cpu);
+		return -1;
+	}
+
+	if (cpufreq_modify_policy_governor(cpu, governor) != 0) {
+		perror("cpufreq_modify_policy_governor");
+		fprintf(stderr, "error: unable to set %s governor\n", governor);
+		return -1;
+	}
+
+	return 0;
+}
+
+/**
+ * sets cpu affinity for the process
+ *
+ * @param cpu cpu# to which the affinity should be set
+ *
+ * @retval 0 on success
+ * @retval -1 when setting the affinity failed
+ **/
+
+int set_cpu_affinity(unsigned int cpu)
+{
+	cpu_set_t cpuset;
+	
+	CPU_ZERO(&cpuset);
+	CPU_SET(cpu, &cpuset);
+
+	dprintf("set affinity to cpu #%u\n", cpu);
+
+	if (sched_setaffinity(getpid(), sizeof(cpu_set_t), &cpuset) < 0) {
+		perror("sched_setaffinity");
+		fprintf(stderr, "warning: unable to set cpu affinity\n");
+		return -1;
+	}
+
+	return 0;
+}
+
+/**
+ * sets the process priority parameter
+ *
+ * @param priority priority value
+ *
+ * @retval 0 on success
+ * @retval -1 when setting the priority failed
+ **/
+
+int set_process_priority(int priority)
+{
+	struct sched_param param;
+
+	dprintf("set scheduler priority to %i\n", priority);
+
+	param.sched_priority = priority;
+
+	if (sched_setscheduler(0, SCHEDULER, &param) < 0) {
+		perror("sched_setscheduler");
+		fprintf(stderr, "warning: unable to set scheduler priority\n");
+		return -1;
+	}
+
+	return 0;
+}
+
+/**
+ * notifys the user that the benchmark may run some time 
+ *
+ * @param config benchmark config values
+ *
+ **/
+
+void prepare_user(const struct config *config)
+{
+	unsigned long sleep_time = 0;
+	unsigned long load_time = 0;
+	unsigned int round;
+	int i;
+
+	for (round = 0; round < config->rounds; round++) {
+		sleep_time +=  2 * config->cycles * (config->sleep + config->sleep_step * round);
+		load_time += 2 * config->cycles * (config->load + config->load_step * round) + (config->load + config->load_step * round * 4);
+	}
+
+	printf("approx. test duration: %im\n", (int)((sleep_time + load_time) / 60000000));
+	printf("your terminal may hardly be responsible while the benchmark is running\n");
+
+	for (i = 5; i >= 0; i--) {
+		printf("\rbenchmark starts in %is", i);
+		fflush(stdout);
+		sleep(1);
+	}
+	printf("\n");
+}
+
+/**
+ * sets up the cpu affinity and scheduler priority
+ *
+ * @param config benchmark config values
+ *
+ **/
+
+void prepare_system(const struct config *config)
+{
+	if (config->verbose)
+		printf("set cpu affinity to cpu #%u\n", config->cpu);
+
+	set_cpu_affinity(config->cpu);
+
+	switch (config->prio) {
+	case SCHED_HIGH:
+		if (config->verbose)
+			printf("high priority condition requested\n");
+
+		set_process_priority(PRIORITY_HIGH);
+		break;
+	case SCHED_LOW:
+		if (config->verbose)
+			printf("low priority condition requested\n");
+
+		set_process_priority(PRIORITY_LOW);
+		break;
+	default:
+		if (config->verbose)
+			printf("default priority condition requested\n");
+
+		set_process_priority(PRIORITY_DEFAULT);
+	}
+}
+
diff --git a/bench/system.h b/bench/system.h
new file mode 100644
index 0000000..3a8c858
--- /dev/null
+++ b/bench/system.h
@@ -0,0 +1,29 @@
+/*  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 "parse.h"
+
+long long get_time();
+
+int set_cpufreq_governor(char *governor, unsigned int cpu);
+int set_cpu_affinity(unsigned int cpu);
+int set_process_priority(int priority);
+
+void prepare_user(const struct config *config);
+void prepare_system(const struct config *config);