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 int sysfs_topology_read_file(unsigned int cpu, const char *fname)
  24 {
  25         unsigned long value;
  26         char linebuf[MAX_LINE_LEN];
  27         char *endp;
  28         char path[SYSFS_PATH_MAX];
  29
  30         snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/topology/%s",
  31                          cpu, fname);
  32         if (sysfs_read_file(path, linebuf, MAX_LINE_LEN) == 0 )
  33                 return -1;
  34         value = strtoul(linebuf, &endp, 0);
  35         if ( endp == linebuf || errno == ERANGE )
  36                 return -1;
  37         return value;
  38 }
  39
  40 struct cpuid_core_info {
  41         unsigned int pkg;
  42         unsigned int thread;
  43         unsigned int cpu;
  44 };
  45
  46 static int __compare(const void *t1, const void *t2)
  47 {
  48         struct cpuid_core_info *top1 = (struct cpuid_core_info *)t1;
  49         struct cpuid_core_info *top2 = (struct cpuid_core_info *)t2;
  50         if (top1->pkg < top2->pkg)
  51                 return -1;
  52         else if (top1->pkg > top2->pkg)
  53                 return 1;
  54         else if (top1->thread < top2->thread)
  55                 return -1;
  56         else if (top1->thread > top2->thread)
  57                 return 1;
  58         else if (top1->cpu < top2->cpu)
  59                 return -1;
  60         else if (top1->cpu > top2->cpu)
  61                 return 1;
  62         else
  63                 return 0;
  64 }
  65
  66 /*
  67  * Returns amount of cpus, negative on error, cpu_top must be
  68  * passed to cpu_topology_release to free resources
  69  *
  70  * Array is sorted after ->pkg, ->core, then ->cpu
  71  */
  72 int get_cpu_topology(struct cpupower_topology *cpu_top)
  73 {
  74         int cpu, cpus = sysconf(_SC_NPROCESSORS_CONF);
  75
  76         cpu_top->core_info = malloc(sizeof(struct cpupower_topology) * cpus);
  77         if (cpu_top->core_info == NULL)
  78                 return -ENOMEM;
  79         cpu_top->pkgs = cpu_top->cores = 0;
  80         for (cpu = 0; cpu < cpus; cpu++) {
  81                 cpu_top->core_info[cpu].pkg =
  82                         sysfs_topology_read_file(cpu, "physical_package_id");
  83                 if ((int)cpu_top->core_info[cpu].pkg != -1 &&
  84                     cpu_top->core_info[cpu].pkg > cpu_top->pkgs)
  85                         cpu_top->pkgs = cpu_top->core_info[cpu].pkg;
  86                 cpu_top->core_info[cpu].core =
  87                         sysfs_topology_read_file(cpu, "core_id");
  88                 cpu_top->core_info[cpu].cpu = cpu;
  89         }
  90         cpu_top->pkgs++;
  91
  92         qsort(cpu_top->core_info, cpus, sizeof(struct cpuid_core_info),
  93               __compare);
  94
  95         /* Intel's cores count is not consecutively numbered, there may
  96          * be a core_id of 3, but none of 2. Assume there always is 0
  97          * Get amount of cores by counting duplicates in a package
  98         for (cpu = 0; cpu_top->core_info[cpu].pkg = 0 && cpu < cpus; cpu++) {
  99                 if (cpu_top->core_info[cpu].core == 0)
 100         cpu_top->cores++;
 101         */
 102         return cpus;
 103 }
 104
 105 void cpu_topology_release(struct cpupower_topology cpu_top)
 106 {
 107         free(cpu_top.core_info);
 108 }