kernel/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 */
  23 static 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
  39 static 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  */
  65 int 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
 113 void cpu_topology_release(struct cpupower_topology cpu_top)
 114 {
 115         free(cpu_top.core_info);
 116 }