cpupowerutils - cpufrequtils extended with quite some features
[linux-2.6.git] / 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 }