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, 671 insertions, 0 deletions

diff --git a/tools/power/cpupower/lib/sysfs.c b/tools/power/cpupower/lib/sysfs.c
new file mode 100644
index 000000000000..c9b061fe87b1
--- /dev/null
+++ b/tools/power/cpupower/lib/sysfs.c
@@ -0,0 +1,671 @@
+/*
+ *  (C) 2004-2009  Dominik Brodowski <linux@dominikbrodowski.de>
+ *
+ *  Licensed under the terms of the GNU GPL License version 2.
+ */
+
+#include <stdio.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <limits.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "cpufreq.h"
+
+#define PATH_TO_CPU "/sys/devices/system/cpu/"
+#define MAX_LINE_LEN 255
+#define SYSFS_PATH_MAX 255
+
+
+static 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;
+}
+
+
+/* CPUFREQ sysfs access **************************************************/
+
+/* helper function to read file from /sys into given buffer */
+/* fname is a relative path under "cpuX/cpufreq" dir */
+static unsigned int sysfs_cpufreq_read_file(unsigned int cpu, const char *fname,
+                                            char *buf, size_t buflen)
+{
+        char path[SYSFS_PATH_MAX];
+
+        snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/cpufreq/%s",
+                         cpu, fname);
+        return sysfs_read_file(path, buf, buflen);
+}
+
+/* helper function to write a new value to a /sys file */
+/* fname is a relative path under "cpuX/cpufreq" dir */
+static unsigned int sysfs_cpufreq_write_file(unsigned int cpu,
+                                             const char *fname,
+                                             const char *value, size_t len)
+{
+        char path[SYSFS_PATH_MAX];
+        int fd;
+        size_t numwrite;
+
+        snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/cpufreq/%s",
+                         cpu, fname);
+
+        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;
+}
+
+/* read access to files which contain one numeric value */
+
+enum cpufreq_value {
+        CPUINFO_CUR_FREQ,
+        CPUINFO_MIN_FREQ,
+        CPUINFO_MAX_FREQ,
+        CPUINFO_LATENCY,
+        SCALING_CUR_FREQ,
+        SCALING_MIN_FREQ,
+        SCALING_MAX_FREQ,
+        STATS_NUM_TRANSITIONS,
+        MAX_CPUFREQ_VALUE_READ_FILES
+};
+
+static const char *cpufreq_value_files[MAX_CPUFREQ_VALUE_READ_FILES] = {
+        [CPUINFO_CUR_FREQ] = "cpuinfo_cur_freq",
+        [CPUINFO_MIN_FREQ] = "cpuinfo_min_freq",
+        [CPUINFO_MAX_FREQ] = "cpuinfo_max_freq",
+        [CPUINFO_LATENCY]  = "cpuinfo_transition_latency",
+        [SCALING_CUR_FREQ] = "scaling_cur_freq",
+        [SCALING_MIN_FREQ] = "scaling_min_freq",
+        [SCALING_MAX_FREQ] = "scaling_max_freq",
+        [STATS_NUM_TRANSITIONS] = "stats/total_trans"
+};
+
+
+static unsigned long sysfs_cpufreq_get_one_value(unsigned int cpu,
+                                                 enum cpufreq_value which)
+{
+        unsigned long value;
+        unsigned int len;
+        char linebuf[MAX_LINE_LEN];
+        char *endp;
+
+        if ( which >= MAX_CPUFREQ_VALUE_READ_FILES )
+                return 0;
+
+        if ( ( len = sysfs_cpufreq_read_file(cpu, cpufreq_value_files[which],
+                                             linebuf, sizeof(linebuf))) == 0 )
+                return 0;
+
+        value = strtoul(linebuf, &endp, 0);
+
+        if ( endp == linebuf || errno == ERANGE )
+                return 0;
+
+        return value;
+}
+
+/* read access to files which contain one string */
+
+enum cpufreq_string {
+        SCALING_DRIVER,
+        SCALING_GOVERNOR,
+        MAX_CPUFREQ_STRING_FILES
+};
+
+static const char *cpufreq_string_files[MAX_CPUFREQ_STRING_FILES] = {
+        [SCALING_DRIVER] = "scaling_driver",
+        [SCALING_GOVERNOR] = "scaling_governor",
+};
+
+
+static char * sysfs_cpufreq_get_one_string(unsigned int cpu,
+                                           enum cpufreq_string which)
+{
+        char linebuf[MAX_LINE_LEN];
+        char *result;
+        unsigned int len;
+
+        if (which >= MAX_CPUFREQ_STRING_FILES)
+                return NULL;
+
+        if ( ( len = sysfs_cpufreq_read_file(cpu, cpufreq_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;
+}
+
+/* write access */
+
+enum cpufreq_write {
+        WRITE_SCALING_MIN_FREQ,
+        WRITE_SCALING_MAX_FREQ,
+        WRITE_SCALING_GOVERNOR,
+        WRITE_SCALING_SET_SPEED,
+        MAX_CPUFREQ_WRITE_FILES
+};
+
+static const char *cpufreq_write_files[MAX_CPUFREQ_WRITE_FILES] = {
+        [WRITE_SCALING_MIN_FREQ] = "scaling_min_freq",
+        [WRITE_SCALING_MAX_FREQ] = "scaling_max_freq",
+        [WRITE_SCALING_GOVERNOR] = "scaling_governor",
+        [WRITE_SCALING_SET_SPEED] = "scaling_setspeed",
+};
+
+static int sysfs_cpufreq_write_one_value(unsigned int cpu,
+                                         enum cpufreq_write which,
+                                         const char *new_value, size_t len)
+{
+        if (which >= MAX_CPUFREQ_WRITE_FILES)
+                return 0;
+
+        if ( sysfs_cpufreq_write_file(cpu, cpufreq_write_files[which],
+                              new_value, len) != len )
+                return -ENODEV;
+
+        return 0;
+};
+
+unsigned long sysfs_get_freq_kernel(unsigned int cpu)
+{
+        return sysfs_cpufreq_get_one_value(cpu, SCALING_CUR_FREQ);
+}
+
+unsigned long sysfs_get_freq_hardware(unsigned int cpu)
+{
+        return sysfs_cpufreq_get_one_value(cpu, CPUINFO_CUR_FREQ);
+}
+
+unsigned long sysfs_get_freq_transition_latency(unsigned int cpu)
+{
+        return sysfs_cpufreq_get_one_value(cpu, CPUINFO_LATENCY);
+}
+
+int sysfs_get_freq_hardware_limits(unsigned int cpu,
+                              unsigned long *min,
+                              unsigned long *max)
+{
+        if ((!min) || (!max))
+                return -EINVAL;
+
+        *min = sysfs_cpufreq_get_one_value(cpu, CPUINFO_MIN_FREQ);
+        if (!*min)
+                return -ENODEV;
+
+        *max = sysfs_cpufreq_get_one_value(cpu, CPUINFO_MAX_FREQ);
+        if (!*max)
+                return -ENODEV;
+
+        return 0;
+}
+
+char * sysfs_get_freq_driver(unsigned int cpu) {
+        return sysfs_cpufreq_get_one_string(cpu, SCALING_DRIVER);
+}
+
+struct cpufreq_policy * sysfs_get_freq_policy(unsigned int cpu) {
+        struct cpufreq_policy *policy;
+
+        policy = malloc(sizeof(struct cpufreq_policy));
+        if (!policy)
+                return NULL;
+
+        policy->governor = sysfs_cpufreq_get_one_string(cpu, SCALING_GOVERNOR);
+        if (!policy->governor) {
+                free(policy);
+                return NULL;
+        }
+        policy->min = sysfs_cpufreq_get_one_value(cpu, SCALING_MIN_FREQ);
+        policy->max = sysfs_cpufreq_get_one_value(cpu, SCALING_MAX_FREQ);
+        if ((!policy->min) || (!policy->max)) {
+                free(policy->governor);
+                free(policy);
+                return NULL;
+        }
+
+        return policy;
+}
+
+struct cpufreq_available_governors *
+sysfs_get_freq_available_governors(unsigned int cpu) {
+        struct cpufreq_available_governors *first = NULL;
+        struct cpufreq_available_governors *current = NULL;
+        char linebuf[MAX_LINE_LEN];
+        unsigned int pos, i;
+        unsigned int len;
+
+        if ( ( len = sysfs_cpufreq_read_file(cpu, "scaling_available_governors",
+                                             linebuf, sizeof(linebuf))) == 0 )
+        {
+                return NULL;
+        }
+
+        pos = 0;
+        for ( i = 0; i < len; i++ )
+        {
+                if ( linebuf[i] == ' ' || linebuf[i] == '\n' )
+                {
+                        if ( i - pos < 2 )
+                                continue;
+                        if ( current ) {
+                                current->next = malloc(sizeof *current );
+                                if ( ! current->next )
+                                        goto error_out;
+                                current = current->next;
+                        } else {
+                                first = malloc( sizeof *first );
+                                if ( ! first )
+                                        goto error_out;
+                                current = first;
+                        }
+                        current->first = first;
+                        current->next = NULL;
+
+                        current->governor = malloc(i - pos + 1);
+                        if ( ! current->governor )
+                                goto error_out;
+
+                        memcpy( current->governor, linebuf + pos, i - pos);
+                        current->governor[i - pos] = '\0';
+                        pos = i + 1;
+                }
+        }
+
+        return first;
+
+ error_out:
+        while ( first ) {
+                current = first->next;
+                if ( first->governor )
+                        free( first->governor );
+                free( first );
+                first = current;
+        }
+        return NULL;
+}
+
+
+struct cpufreq_available_frequencies *
+sysfs_get_available_frequencies(unsigned int cpu) {
+        struct cpufreq_available_frequencies *first = NULL;
+        struct cpufreq_available_frequencies *current = NULL;
+        char one_value[SYSFS_PATH_MAX];
+        char linebuf[MAX_LINE_LEN];
+        unsigned int pos, i;
+        unsigned int len;
+
+        if ( ( len = sysfs_cpufreq_read_file(cpu,
+                                             "scaling_available_frequencies",
+                                             linebuf, sizeof(linebuf))) == 0 )
+        {
+                return NULL;
+        }
+
+        pos = 0;
+        for ( i = 0; i < len; i++ )
+        {
+                if ( linebuf[i] == ' ' || linebuf[i] == '\n' )
+                {
+                        if ( i - pos < 2 )
+                                continue;
+                        if ( i - pos >= SYSFS_PATH_MAX )
+                                goto error_out;
+                        if ( current ) {
+                                current->next = malloc(sizeof *current );
+                                if ( ! current->next )
+                                        goto error_out;
+                                current = current->next;
+                        } else {
+                                first = malloc(sizeof *first );
+                                if ( ! first )
+                                        goto error_out;
+                                current = first;
+                        }
+                        current->first = first;
+                        current->next = NULL;
+
+                        memcpy(one_value, linebuf + pos, i - pos);
+                        one_value[i - pos] = '\0';
+                        if ( sscanf(one_value, "%lu", &current->frequency) != 1 )
+                                goto error_out;
+
+                        pos = i + 1;
+                }
+        }
+
+        return first;
+
+ error_out:
+        while ( first ) {
+                current = first->next;
+                free(first);
+                first = current;
+        }
+        return NULL;
+}
+
+static struct cpufreq_affected_cpus * sysfs_get_cpu_list(unsigned int cpu,
+                                                         const char *file) {
+        struct cpufreq_affected_cpus *first = NULL;
+        struct cpufreq_affected_cpus *current = NULL;
+        char one_value[SYSFS_PATH_MAX];
+        char linebuf[MAX_LINE_LEN];
+        unsigned int pos, i;
+        unsigned int len;
+
+        if ( ( len = sysfs_cpufreq_read_file(cpu, file, linebuf,
+                                             sizeof(linebuf))) == 0 )
+        {
+                return NULL;
+        }
+
+        pos = 0;
+        for ( i = 0; i < len; i++ )
+        {
+                if ( i == len || linebuf[i] == ' ' || linebuf[i] == '\n' )
+                {
+                        if ( i - pos  < 1 )
+                                continue;
+                        if ( i - pos >= SYSFS_PATH_MAX )
+                                goto error_out;
+                        if ( current ) {
+                                current->next = malloc(sizeof *current);
+                                if ( ! current->next )
+                                        goto error_out;
+                                current = current->next;
+                        } else {
+                                first = malloc(sizeof *first);
+                                if ( ! first )
+                                        goto error_out;
+                                current = first;
+                        }
+                        current->first = first;
+                        current->next = NULL;
+
+                        memcpy(one_value, linebuf + pos, i - pos);
+                        one_value[i - pos] = '\0';
+
+                        if ( sscanf(one_value, "%u", &current->cpu) != 1 )
+                                goto error_out;
+
+                        pos = i + 1;
+                }
+        }
+
+        return first;
+
+ error_out:
+        while (first) {
+                current = first->next;
+                free(first);
+                first = current;
+        }
+        return NULL;
+}
+
+struct cpufreq_affected_cpus * sysfs_get_freq_affected_cpus(unsigned int cpu) {
+        return sysfs_get_cpu_list(cpu, "affected_cpus");
+}
+
+struct cpufreq_affected_cpus * sysfs_get_freq_related_cpus(unsigned int cpu) {
+        return sysfs_get_cpu_list(cpu, "related_cpus");
+}
+
+struct cpufreq_stats * sysfs_get_freq_stats(unsigned int cpu, unsigned long long *total_time) {
+        struct cpufreq_stats *first = NULL;
+        struct cpufreq_stats *current = NULL;
+        char one_value[SYSFS_PATH_MAX];
+        char linebuf[MAX_LINE_LEN];
+        unsigned int pos, i;
+        unsigned int len;
+
+        if ( ( len = sysfs_cpufreq_read_file(cpu, "stats/time_in_state",
+                                             linebuf, sizeof(linebuf))) == 0 )
+                return NULL;
+
+        *total_time = 0;
+        pos = 0;
+        for ( i = 0; i < len; i++ )
+        {
+                if ( i == strlen(linebuf) || linebuf[i] == '\n' )
+                {
+                        if ( i - pos < 2 )
+                                continue;
+                        if ( (i - pos) >= SYSFS_PATH_MAX )
+                                goto error_out;
+                        if ( current ) {
+                                current->next = malloc(sizeof *current );
+                                if ( ! current->next )
+                                        goto error_out;
+                                current = current->next;
+                        } else {
+                                first = malloc(sizeof *first );
+                                if ( ! first )
+                                        goto error_out;
+                                current = first;
+                        }
+                        current->first = first;
+                        current->next = NULL;
+
+                        memcpy(one_value, linebuf + pos, i - pos);
+                        one_value[i - pos] = '\0';
+                        if ( sscanf(one_value, "%lu %llu", &current->frequency, &current->time_in_state) != 2 )
+                                goto error_out;
+
+                        *total_time = *total_time + current->time_in_state;
+                        pos = i + 1;
+                }
+        }
+
+        return first;
+
+ error_out:
+        while ( first ) {
+                current = first->next;
+                free(first);
+                first = current;
+        }
+        return NULL;
+}
+
+unsigned long sysfs_get_freq_transitions(unsigned int cpu)
+{
+        return sysfs_cpufreq_get_one_value(cpu, STATS_NUM_TRANSITIONS);
+}
+
+static int verify_gov(char *new_gov, char *passed_gov)
+{
+        unsigned int i, j=0;
+
+        if (!passed_gov || (strlen(passed_gov) > 19))
+                return -EINVAL;
+
+        strncpy(new_gov, passed_gov, 20);
+        for (i=0;i<20;i++) {
+                if (j) {
+                        new_gov[i] = '\0';
+                        continue;
+                }
+                if ((new_gov[i] >= 'a') && (new_gov[i] <= 'z')) {
+                        continue;
+                }
+                if ((new_gov[i] >= 'A') && (new_gov[i] <= 'Z')) {
+                        continue;
+                }
+                if (new_gov[i] == '-') {
+                        continue;
+                }
+                if (new_gov[i] == '_') {
+                        continue;
+                }
+                if (new_gov[i] == '\0') {
+                        j = 1;
+                        continue;
+                }
+                return -EINVAL;
+        }
+        new_gov[19] = '\0';
+        return 0;
+}
+
+int sysfs_modify_freq_policy_governor(unsigned int cpu, char *governor)
+{
+        char new_gov[SYSFS_PATH_MAX];
+
+        if (!governor)
+                return -EINVAL;
+
+        if (verify_gov(new_gov, governor))
+                return -EINVAL;
+
+        return sysfs_cpufreq_write_one_value(cpu, WRITE_SCALING_GOVERNOR,
+                                             new_gov, strlen(new_gov));
+};
+
+int sysfs_modify_freq_policy_max(unsigned int cpu, unsigned long max_freq)
+{
+        char value[SYSFS_PATH_MAX];
+
+        snprintf(value, SYSFS_PATH_MAX, "%lu", max_freq);
+
+        return sysfs_cpufreq_write_one_value(cpu, WRITE_SCALING_MAX_FREQ,
+                                             value, strlen(value));
+};
+
+
+int sysfs_modify_freq_policy_min(unsigned int cpu, unsigned long min_freq)
+{
+        char value[SYSFS_PATH_MAX];
+
+        snprintf(value, SYSFS_PATH_MAX, "%lu", min_freq);
+
+        return sysfs_cpufreq_write_one_value(cpu, WRITE_SCALING_MIN_FREQ,
+                                             value, strlen(value));
+};
+
+
+int sysfs_set_freq_policy(unsigned int cpu, struct cpufreq_policy *policy)
+{
+        char min[SYSFS_PATH_MAX];
+        char max[SYSFS_PATH_MAX];
+        char gov[SYSFS_PATH_MAX];
+        int ret;
+        unsigned long old_min;
+        int write_max_first;
+
+        if (!policy || !(policy->governor))
+                return -EINVAL;
+
+        if (policy->max < policy->min)
+                return -EINVAL;
+
+        if (verify_gov(gov, policy->governor))
+                return -EINVAL;
+
+        snprintf(min, SYSFS_PATH_MAX, "%lu", policy->min);
+        snprintf(max, SYSFS_PATH_MAX, "%lu", policy->max);
+
+        old_min = sysfs_cpufreq_get_one_value(cpu, SCALING_MIN_FREQ);
+        write_max_first = (old_min && (policy->max < old_min) ? 0 : 1);
+
+        if (write_max_first) {
+                ret = sysfs_cpufreq_write_one_value(cpu, WRITE_SCALING_MAX_FREQ,
+                                                    max, strlen(max));
+                if (ret)
+                        return ret;
+        }
+
+        ret = sysfs_cpufreq_write_one_value(cpu, WRITE_SCALING_MIN_FREQ, min,
+                                            strlen(min));
+        if (ret)
+                return ret;
+
+        if (!write_max_first) {
+                ret = sysfs_cpufreq_write_one_value(cpu, WRITE_SCALING_MAX_FREQ,
+                                                    max, strlen(max));
+                if (ret)
+                        return ret;
+        }
+
+        return sysfs_cpufreq_write_one_value(cpu, WRITE_SCALING_GOVERNOR,
+                                             gov, strlen(gov));
+}
+
+int sysfs_set_frequency(unsigned int cpu, unsigned long target_frequency) {
+        struct cpufreq_policy *pol = sysfs_get_freq_policy(cpu);
+        char userspace_gov[] = "userspace";
+        char freq[SYSFS_PATH_MAX];
+        int ret;
+
+        if (!pol)
+                return -ENODEV;
+
+        if (strncmp(pol->governor, userspace_gov, 9) != 0) {
+                ret = sysfs_modify_freq_policy_governor(cpu, userspace_gov);
+                if (ret) {
+                        cpufreq_put_policy(pol);
+                        return (ret);
+                }
+        }
+
+        cpufreq_put_policy(pol);
+
+        snprintf(freq, SYSFS_PATH_MAX, "%lu", target_frequency);
+
+        return sysfs_cpufreq_write_one_value(cpu, WRITE_SCALING_SET_SPEED,
+                                             freq, strlen(freq));
+}
+
+/* CPUFREQ sysfs access **************************************************/
+
+/* General sysfs access **************************************************/
+int sysfs_cpu_exists(unsigned int cpu)
+{
+        char file[SYSFS_PATH_MAX];
+        struct stat statbuf;
+
+        snprintf(file, SYSFS_PATH_MAX, PATH_TO_CPU "cpu%u/", cpu);
+
+        if ( stat(file, &statbuf) != 0 )
+                return -ENOSYS;
+
+        return S_ISDIR(statbuf.st_mode) ? 0 : -ENOSYS;
+}
+
+/* General sysfs access **************************************************/