diff options
Diffstat (limited to 'tools/power/cpupower/lib/cpupower.c')
| -rw-r--r-- | tools/power/cpupower/lib/cpupower.c | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/tools/power/cpupower/lib/cpupower.c b/tools/power/cpupower/lib/cpupower.c new file mode 100644 index 000000000..3f7d0c0c5 --- /dev/null +++ b/tools/power/cpupower/lib/cpupower.c @@ -0,0 +1,212 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * (C) 2004-2009 Dominik Brodowski <linux@dominikbrodowski.de> + */ + +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <unistd.h> +#include <stdio.h> +#include <errno.h> +#include <stdlib.h> + +#include "cpupower.h" +#include "cpupower_intern.h" + +unsigned int cpupower_read_sysfs(const char *path, char *buf, size_t buflen) +{ + ssize_t numread; + int fd; + + fd = open(path, O_RDONLY); + if (fd == -1) + return 0; + + numread = read(fd, buf, buflen - 1); + if (numread < 1) { + close(fd); + return 0; + } + + buf[numread] = '\0'; + close(fd); + + return (unsigned int) numread; +} + +unsigned int cpupower_write_sysfs(const char *path, char *buf, size_t buflen) +{ + ssize_t numwritten; + int fd; + + fd = open(path, O_WRONLY); + if (fd == -1) + return 0; + + numwritten = write(fd, buf, buflen - 1); + if (numwritten < 1) { + perror(path); + close(fd); + return -1; + } + + close(fd); + + return (unsigned int) numwritten; +} + +/* + * Detect whether a CPU is online + * + * Returns: + * 1 -> if CPU is online + * 0 -> if CPU is offline + * negative errno values in error case + */ +int cpupower_is_cpu_online(unsigned int cpu) +{ + char path[SYSFS_PATH_MAX]; + int fd; + ssize_t numread; + unsigned long long value; + char linebuf[MAX_LINE_LEN]; + char *endp; + struct stat statbuf; + + snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u", cpu); + + if (stat(path, &statbuf) != 0) + return 0; + + /* + * kernel without CONFIG_HOTPLUG_CPU + * -> cpuX directory exists, but not cpuX/online file + */ + snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/online", cpu); + if (stat(path, &statbuf) != 0) + return 1; + + fd = open(path, O_RDONLY); + if (fd == -1) + return -errno; + + numread = read(fd, linebuf, MAX_LINE_LEN - 1); + if (numread < 1) { + close(fd); + return -EIO; + } + linebuf[numread] = '\0'; + close(fd); + + value = strtoull(linebuf, &endp, 0); + if (value > 1) + return -EINVAL; + + return value; +} + +/* returns -1 on failure, 0 on success */ +static int sysfs_topology_read_file(unsigned int cpu, const char *fname, int *result) +{ + char linebuf[MAX_LINE_LEN]; + char *endp; + char path[SYSFS_PATH_MAX]; + + snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/topology/%s", + cpu, fname); + if (cpupower_read_sysfs(path, linebuf, MAX_LINE_LEN) == 0) + return -1; + *result = strtol(linebuf, &endp, 0); + if (endp == linebuf || errno == ERANGE) + return -1; + return 0; +} + +static int __compare(const void *t1, const void *t2) +{ + struct cpuid_core_info *top1 = (struct cpuid_core_info *)t1; + struct cpuid_core_info *top2 = (struct cpuid_core_info *)t2; + if (top1->pkg < top2->pkg) + return -1; + else if (top1->pkg > top2->pkg) + return 1; + else if (top1->core < top2->core) + return -1; + else if (top1->core > top2->core) + return 1; + else if (top1->cpu < top2->cpu) + return -1; + else if (top1->cpu > top2->cpu) + return 1; + else + return 0; +} + +/* + * Returns amount of cpus, negative on error, cpu_top must be + * passed to cpu_topology_release to free resources + * + * Array is sorted after ->pkg, ->core, then ->cpu + */ +int get_cpu_topology(struct cpupower_topology *cpu_top) +{ + int cpu, last_pkg, cpus = sysconf(_SC_NPROCESSORS_CONF); + + cpu_top->core_info = malloc(sizeof(struct cpuid_core_info) * cpus); + if (cpu_top->core_info == NULL) + return -ENOMEM; + cpu_top->pkgs = cpu_top->cores = 0; + for (cpu = 0; cpu < cpus; cpu++) { + cpu_top->core_info[cpu].cpu = cpu; + cpu_top->core_info[cpu].is_online = cpupower_is_cpu_online(cpu); + if(sysfs_topology_read_file( + cpu, + "physical_package_id", + &(cpu_top->core_info[cpu].pkg)) < 0) { + cpu_top->core_info[cpu].pkg = -1; + cpu_top->core_info[cpu].core = -1; + continue; + } + if(sysfs_topology_read_file( + cpu, + "core_id", + &(cpu_top->core_info[cpu].core)) < 0) { + cpu_top->core_info[cpu].pkg = -1; + cpu_top->core_info[cpu].core = -1; + continue; + } + } + + qsort(cpu_top->core_info, cpus, sizeof(struct cpuid_core_info), + __compare); + + /* Count the number of distinct pkgs values. This works + because the primary sort of the core_info struct was just + done by pkg value. */ + last_pkg = cpu_top->core_info[0].pkg; + for(cpu = 1; cpu < cpus; cpu++) { + if (cpu_top->core_info[cpu].pkg != last_pkg && + cpu_top->core_info[cpu].pkg != -1) { + + last_pkg = cpu_top->core_info[cpu].pkg; + cpu_top->pkgs++; + } + } + if (!(cpu_top->core_info[0].pkg == -1)) + cpu_top->pkgs++; + + /* Intel's cores count is not consecutively numbered, there may + * be a core_id of 3, but none of 2. Assume there always is 0 + * Get amount of cores by counting duplicates in a package + for (cpu = 0; cpu_top->core_info[cpu].pkg = 0 && cpu < cpus; cpu++) { + if (cpu_top->core_info[cpu].core == 0) + cpu_top->cores++; + */ + return cpus; +} + +void cpu_topology_release(struct cpupower_topology cpu_top) +{ + free(cpu_top.core_info); +} |