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, 350 insertions, 0 deletions

diff --git a/tools/power/cpupower/utils/helpers/sysfs.c b/tools/power/cpupower/utils/helpers/sysfs.c
new file mode 100644
index 000000000000..0c534e79652b
--- /dev/null
+++ b/tools/power/cpupower/utils/helpers/sysfs.c
@@ -0,0 +1,350 @@
+/*
+ *  (C) 2004-2009  Dominik Brodowski <linux@dominikbrodowski.de>
+ *  (C) 2011       Thomas Renninger <trenn@novell.com> Novell Inc.
+ *
+ *  Licensed under the terms of the GNU GPL License version 2.
+ */
+
+#include <stdio.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "helpers/sysfs.h"
+
+unsigned int sysfs_read_file(const char *path, char *buf, size_t buflen)
+{
+	int fd;
+	size_t numread;
+
+	if ( ( fd = open(path, O_RDONLY) ) == -1 )
+		return 0;
+
+	numread = read(fd, buf, buflen - 1);
+	if ( numread < 1 )
+	{
+		close(fd);
+		return 0;
+	}
+
+	buf[numread] = '\0';
+	close(fd);
+
+	return numread;
+}
+
+static unsigned int sysfs_write_file(const char *path,
+				     const char *value, size_t len)
+{
+	int fd;
+	size_t numwrite;
+
+	if ( ( fd = open(path, O_WRONLY) ) == -1 )
+		return 0;
+
+	numwrite = write(fd, value, len);
+	if ( numwrite < 1 )
+	{
+		close(fd);
+		return 0;
+	}
+	close(fd);
+	return numwrite;
+}
+
+/* CPUidle idlestate specific /sys/devices/system/cpu/cpuX/cpuidle/ access */
+
+/*
+ * helper function to read file from /sys into given buffer
+ * fname is a relative path under "cpuX/cpuidle/stateX/" dir
+ * cstates starting with 0, C0 is not counted as cstate.
+ * This means if you want C1 info, pass 0 as idlestate param
+ */
+unsigned int sysfs_idlestate_read_file(unsigned int cpu, unsigned int idlestate,
+			     const char *fname, char *buf, size_t buflen)
+{
+	char path[SYSFS_PATH_MAX];
+	int fd;
+	size_t numread;
+
+	snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/cpuidle/state%u/%s",
+		 cpu, idlestate, fname);
+
+	if ( ( fd = open(path, O_RDONLY) ) == -1 )
+		return 0;
+
+	numread = read(fd, buf, buflen - 1);
+	if ( numread < 1 )
+	{
+		close(fd);
+		return 0;
+	}
+
+	buf[numread] = '\0';
+	close(fd);
+
+	return numread;
+}
+
+/* read access to files which contain one numeric value */
+
+enum idlestate_value {
+	IDLESTATE_USAGE,
+	IDLESTATE_POWER,
+	IDLESTATE_LATENCY,
+	IDLESTATE_TIME,
+	MAX_IDLESTATE_VALUE_FILES
+};
+
+static const char *idlestate_value_files[MAX_IDLESTATE_VALUE_FILES] = {
+	[IDLESTATE_USAGE] = "usage",
+	[IDLESTATE_POWER] = "power",
+	[IDLESTATE_LATENCY] = "latency",
+	[IDLESTATE_TIME]  = "time",
+};
+
+static unsigned long long sysfs_idlestate_get_one_value(unsigned int cpu,
+						     unsigned int idlestate,
+						     enum idlestate_value which)
+{
+	unsigned long long value;
+	unsigned int len;
+	char linebuf[MAX_LINE_LEN];
+	char *endp;
+
+	if ( which >= MAX_IDLESTATE_VALUE_FILES )
+		return 0;
+
+	if ( ( len = sysfs_idlestate_read_file(cpu, idlestate,
+					    idlestate_value_files[which],
+					    linebuf, sizeof(linebuf))) == 0 )
+	{
+		return 0;
+	}
+
+	value = strtoull(linebuf, &endp, 0);
+
+	if ( endp == linebuf || errno == ERANGE )
+		return 0;
+
+	return value;
+}
+
+/* read access to files which contain one string */
+
+enum idlestate_string {
+	IDLESTATE_DESC,
+	IDLESTATE_NAME,
+	MAX_IDLESTATE_STRING_FILES
+};
+
+static const char *idlestate_string_files[MAX_IDLESTATE_STRING_FILES] = {
+	[IDLESTATE_DESC] = "desc",
+	[IDLESTATE_NAME] = "name",
+};
+
+
+static char * sysfs_idlestate_get_one_string(unsigned int cpu,
+					  unsigned int idlestate,
+					  enum idlestate_string which)
+{
+	char linebuf[MAX_LINE_LEN];
+	char *result;
+	unsigned int len;
+
+	if (which >= MAX_IDLESTATE_STRING_FILES)
+		return NULL;
+
+	if ( ( len = sysfs_idlestate_read_file(cpu, idlestate,
+					    idlestate_string_files[which],
+					    linebuf, sizeof(linebuf))) == 0 )
+		return NULL;
+
+	if ( ( result = strdup(linebuf) ) == NULL )
+		return NULL;
+
+	if (result[strlen(result) - 1] == '\n')
+		result[strlen(result) - 1] = '\0';
+
+	return result;
+}
+
+unsigned long sysfs_get_idlestate_latency(unsigned int cpu, unsigned int idlestate)
+{
+	return sysfs_idlestate_get_one_value(cpu, idlestate, IDLESTATE_LATENCY);
+}
+
+unsigned long sysfs_get_idlestate_usage(unsigned int cpu, unsigned int idlestate)
+{
+	return sysfs_idlestate_get_one_value(cpu, idlestate, IDLESTATE_USAGE);
+}
+
+unsigned long long sysfs_get_idlestate_time(unsigned int cpu, unsigned int idlestate)
+{
+	return sysfs_idlestate_get_one_value(cpu, idlestate, IDLESTATE_TIME);
+}
+
+char * sysfs_get_idlestate_name(unsigned int cpu, unsigned int idlestate)
+{
+	return sysfs_idlestate_get_one_string(cpu, idlestate, IDLESTATE_NAME);
+}
+
+char * sysfs_get_idlestate_desc(unsigned int cpu, unsigned int idlestate)
+{
+	return sysfs_idlestate_get_one_string(cpu, idlestate, IDLESTATE_DESC);
+}
+
+/*
+ * Returns number of supported C-states of CPU core cpu
+ * Negativ in error case
+ * Zero if cpuidle does not export any C-states
+ */
+int sysfs_get_idlestate_count(unsigned int cpu)
+{
+	char file[SYSFS_PATH_MAX];
+	struct stat statbuf;
+	int idlestates = 1;
+
+
+	snprintf(file, SYSFS_PATH_MAX, PATH_TO_CPU "cpuidle");
+	if ( stat(file, &statbuf) != 0 || !S_ISDIR(statbuf.st_mode))
+		return -ENODEV;
+
+	snprintf(file, SYSFS_PATH_MAX, PATH_TO_CPU "cpu%u/cpuidle/state0", cpu);
+	if ( stat(file, &statbuf) != 0 || !S_ISDIR(statbuf.st_mode))
+		return 0;
+
+	while(stat(file, &statbuf) == 0 && S_ISDIR(statbuf.st_mode)) {
+		snprintf(file, SYSFS_PATH_MAX, PATH_TO_CPU
+			 "cpu%u/cpuidle/state%d", cpu, idlestates);
+		idlestates++;
+	}
+	idlestates--;
+	return idlestates;
+}
+
+/* CPUidle general /sys/devices/system/cpu/cpuidle/ sysfs access ********/
+
+/*
+ * helper function to read file from /sys into given buffer
+ * fname is a relative path under "cpu/cpuidle/" dir
+ */
+static unsigned int sysfs_cpuidle_read_file(const char *fname, char *buf,
+					    size_t buflen)
+{
+	char path[SYSFS_PATH_MAX];
+
+	snprintf(path, sizeof(path), PATH_TO_CPU "cpuidle/%s", fname);
+
+	return sysfs_read_file(path, buf, buflen);
+}
+
+
+
+/* read access to files which contain one string */
+
+enum cpuidle_string {
+	CPUIDLE_GOVERNOR,
+	CPUIDLE_GOVERNOR_RO,
+	CPUIDLE_DRIVER,
+	MAX_CPUIDLE_STRING_FILES
+};
+
+static const char *cpuidle_string_files[MAX_CPUIDLE_STRING_FILES] = {
+	[CPUIDLE_GOVERNOR]	= "current_governor",
+	[CPUIDLE_GOVERNOR_RO]	= "current_governor_ro",
+	[CPUIDLE_DRIVER]	= "current_driver",
+};
+
+
+static char * sysfs_cpuidle_get_one_string(enum cpuidle_string which)
+{
+	char linebuf[MAX_LINE_LEN];
+	char *result;
+	unsigned int len;
+
+	if (which >= MAX_CPUIDLE_STRING_FILES)
+		return NULL;
+
+	if ( ( len = sysfs_cpuidle_read_file(cpuidle_string_files[which],
+					    linebuf, sizeof(linebuf))) == 0 )
+		return NULL;
+
+	if ( ( result = strdup(linebuf) ) == NULL )
+		return NULL;
+
+	if (result[strlen(result) - 1] == '\n')
+		result[strlen(result) - 1] = '\0';
+
+	return result;
+}
+
+char * sysfs_get_cpuidle_governor(void)
+{
+	char *tmp = sysfs_cpuidle_get_one_string(CPUIDLE_GOVERNOR_RO);
+	if (!tmp)
+		return sysfs_cpuidle_get_one_string(CPUIDLE_GOVERNOR);
+	else
+		return tmp;
+}
+
+char * sysfs_get_cpuidle_driver(void)
+{
+	return sysfs_cpuidle_get_one_string(CPUIDLE_DRIVER);
+}
+/* CPUidle idlestate specific /sys/devices/system/cpu/cpuX/cpuidle/ access */
+
+/*
+ * Get sched_mc or sched_smt settings
+ * Pass "mc" or "smt" as argument
+ *
+ * Returns negative value on failure
+ */
+int sysfs_get_sched(const char* smt_mc)
+{
+ 	unsigned long value;
+	char linebuf[MAX_LINE_LEN];
+	char *endp;
+	char path[SYSFS_PATH_MAX];
+
+	if (strcmp("mc", smt_mc) && strcmp("smt", smt_mc))
+		return -EINVAL;
+
+	snprintf(path, sizeof(path), PATH_TO_CPU "sched_%s_power_savings", smt_mc);
+	if (sysfs_read_file(path, linebuf, MAX_LINE_LEN) == 0 )
+		return -1;
+	value = strtoul(linebuf, &endp, 0);
+	if ( endp == linebuf || errno == ERANGE )
+		return -1;
+	return value;
+}
+
+/*
+ * Get sched_mc or sched_smt settings
+ * Pass "mc" or "smt" as argument
+ *
+ * Returns negative value on failure
+ */
+int sysfs_set_sched(const char* smt_mc, int val)
+{
+	char linebuf[MAX_LINE_LEN];
+	char path[SYSFS_PATH_MAX];
+	struct stat statbuf;
+
+	if (strcmp("mc", smt_mc) && strcmp("smt", smt_mc))
+		return -EINVAL;
+
+	snprintf(path, sizeof(path), PATH_TO_CPU "sched_%s_power_savings", smt_mc);
+	sprintf(linebuf, "%d", val);
+
+	if ( stat(path, &statbuf) != 0 )
+		return -ENODEV;
+
+	if (sysfs_write_file(path, linebuf, MAX_LINE_LEN) == 0 )
+		return -1;
+	return 0;
+}