1 /*
2 * Copyright © 2013 Intel Corporation
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
13 * Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
21 * IN THE SOFTWARE.
22 *
23 */
24
25 #include <stdio.h>
26 #include <stdlib.h>
27 #include <unistd.h>
28 #include <fcntl.h>
29 #include <string.h>
30 #include <errno.h>
31
32 #include "cpu-top.h"
33
cpu_top_init(struct cpu_top * cpu)34 int cpu_top_init(struct cpu_top *cpu)
35 {
36 memset(cpu, 0, sizeof(*cpu));
37
38 cpu->nr_cpu = sysconf(_SC_NPROCESSORS_ONLN);
39
40 return 0;
41 }
42
cpu_top_update(struct cpu_top * cpu)43 int cpu_top_update(struct cpu_top *cpu)
44 {
45 struct cpu_stat *s = &cpu->stat[cpu->count++&1];
46 struct cpu_stat *d = &cpu->stat[cpu->count&1];
47 uint64_t d_total, d_idle;
48 char buf[4096], *b;
49 int fd, len = -1;
50
51 fd = open("/proc/stat", 0);
52 if (fd < 0)
53 return errno;
54
55 len = read(fd, buf, sizeof(buf)-1);
56 close(fd);
57
58 if (len < 0)
59 return EIO;
60 buf[len] = '\0';
61
62 #ifdef __x86_64__
63 sscanf(buf, "cpu %lu %lu %lu %lu",
64 &s->user, &s->nice, &s->sys, &s->idle);
65 #else
66 sscanf(buf, "cpu %llu %llu %llu %llu",
67 &s->user, &s->nice, &s->sys, &s->idle);
68 #endif
69
70 b = strstr(buf, "procs_running");
71 if (b)
72 cpu->nr_running = atoi(b+sizeof("procs_running")) - 1;
73
74 s->total = s->user + s->nice + s->sys + s->idle;
75 if (cpu->count == 1)
76 return EAGAIN;
77
78 d_total = s->total - d->total;
79 d_idle = s->idle - d->idle;
80 cpu->busy = 100 - 100 * d_idle / d_total;
81
82 return 0;
83 }
84