LXR linux/tools/power/cpupower/utils/helpers/topology.c

   1/*
   2 *  (C) 2010,2011       Thomas Renninger <trenn@suse.de>, Novell Inc.
   3 *
   4 *  Licensed under the terms of the GNU GPL License version 2.
   5 *
   6 * ToDo: Needs to be done more properly for AMD/Intel specifics
   7 */
   8
   9/* Helper struct for qsort, must be in sync with cpupower_topology.cpu_info */
  10/* Be careful: Need to pass unsigned to the sort, so that offlined cores are
  11   in the end, but double check for -1 for offlined cpus at other places */
  12
  13#include <stdlib.h>
  14#include <stdio.h>
  15#include <unistd.h>
  16#include <errno.h>
  17#include <fcntl.h>
  18
  19#include <helpers/helpers.h>
  20#include <helpers/sysfs.h>
  21
  22/* returns -1 on failure, 0 on success */
  23static int sysfs_topology_read_file(unsigned int cpu, const char *fname, int *result)
  24{
  25        char linebuf[MAX_LINE_LEN];
  26        char *endp;
  27        char path[SYSFS_PATH_MAX];
  28
  29        snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/topology/%s",
  30                         cpu, fname);
  31        if (sysfs_read_file(path, linebuf, MAX_LINE_LEN) == 0)
  32                return -1;
  33        *result = strtol(linebuf, &endp, 0);
  34        if (endp == linebuf || errno == ERANGE)
  35                return -1;
  36        return 0;
  37}
  38
  39static int __compare(const void *t1, const void *t2)
  40{
  41        struct cpuid_core_info *top1 = (struct cpuid_core_info *)t1;
  42        struct cpuid_core_info *top2 = (struct cpuid_core_info *)t2;
  43        if (top1->pkg < top2->pkg)
  44                return -1;
  45        else if (top1->pkg > top2->pkg)
  46                return 1;
  47        else if (top1->core < top2->core)
  48                return -1;
  49        else if (top1->core > top2->core)
  50                return 1;
  51        else if (top1->cpu < top2->cpu)
  52                return -1;
  53        else if (top1->cpu > top2->cpu)
  54                return 1;
  55        else
  56                return 0;
  57}
  58
  59/*
  60 * Returns amount of cpus, negative on error, cpu_top must be
  61 * passed to cpu_topology_release to free resources
  62 *
  63 * Array is sorted after ->pkg, ->core, then ->cpu
  64 */
  65int get_cpu_topology(struct cpupower_topology *cpu_top)
  66{
  67        int cpu, last_pkg, cpus = sysconf(_SC_NPROCESSORS_CONF);
  68
  69        cpu_top->core_info = malloc(sizeof(struct cpuid_core_info) * cpus);
  70        if (cpu_top->core_info == NULL)
  71                return -ENOMEM;
  72        cpu_top->pkgs = cpu_top->cores = 0;
  73        for (cpu = 0; cpu < cpus; cpu++) {
  74                cpu_top->core_info[cpu].cpu = cpu;
  75                cpu_top->core_info[cpu].is_online = sysfs_is_cpu_online(cpu);
  76                if(sysfs_topology_read_file(
  77                        cpu,
  78                        "physical_package_id",
  79                        &(cpu_top->core_info[cpu].pkg)) < 0)
  80                        return -1;
  81                if(sysfs_topology_read_file(
  82                        cpu,
  83                        "core_id",
  84                        &(cpu_top->core_info[cpu].core)) < 0)
  85                        return -1;
  86        }
  87
  88        qsort(cpu_top->core_info, cpus, sizeof(struct cpuid_core_info),
  89              __compare);
  90
  91        /* Count the number of distinct pkgs values. This works
  92           because the primary sort of the core_info struct was just
  93           done by pkg value. */
  94        last_pkg = cpu_top->core_info[0].pkg;
  95        for(cpu = 1; cpu < cpus; cpu++) {
  96                if(cpu_top->core_info[cpu].pkg != last_pkg) {
  97                        last_pkg = cpu_top->core_info[cpu].pkg;
  98                        cpu_top->pkgs++;
  99                }
 100        }
 101        cpu_top->pkgs++;
 102
 103        /* Intel's cores count is not consecutively numbered, there may
 104         * be a core_id of 3, but none of 2. Assume there always is 0
 105         * Get amount of cores by counting duplicates in a package
 106        for (cpu = 0; cpu_top->core_info[cpu].pkg = 0 && cpu < cpus; cpu++) {
 107                if (cpu_top->core_info[cpu].core == 0)
 108        cpu_top->cores++;
 109        */
 110        return cpus;
 111}
 112
 113void cpu_topology_release(struct cpupower_topology cpu_top)
 114{
 115        free(cpu_top.core_info);
 116}
 117