Denys Vlasenko | c9b9750 | 2010-08-16 02:49:21 +0200 | [diff] [blame] | 1 | /* vi: set sw=4 ts=4: */ |
| 2 | /* |
| 3 | * Factored out of mpstat/iostat. |
| 4 | * |
| 5 | * Copyright (C) 2010 Marek Polacek <mmpolacek@gmail.com> |
| 6 | * |
Denys Vlasenko | 9768a82 | 2010-08-16 03:04:14 +0200 | [diff] [blame] | 7 | * Licensed under GPLv2, see file LICENSE in this tarball for details. |
Denys Vlasenko | c9b9750 | 2010-08-16 02:49:21 +0200 | [diff] [blame] | 8 | */ |
| 9 | #include "libbb.h" |
| 10 | |
| 11 | /* Does str start with "cpu"? */ |
| 12 | int FAST_FUNC starts_with_cpu(const char *str) |
| 13 | { |
| 14 | return ((str[0] - 'c') | (str[1] - 'p') | (str[2] - 'u')) == 0; |
| 15 | } |
| 16 | |
| 17 | /* |
| 18 | * Get number of processors. Uses /proc/stat. |
| 19 | * Return value 0 means one CPU and non SMP kernel. |
| 20 | * Otherwise N means N processor(s) and SMP kernel. |
| 21 | */ |
| 22 | unsigned FAST_FUNC get_cpu_count(void) |
| 23 | { |
| 24 | FILE *fp; |
| 25 | char line[256]; |
| 26 | int proc_nr = -1; |
| 27 | |
| 28 | fp = xfopen_for_read("/proc/stat"); |
| 29 | while (fgets(line, sizeof(line), fp)) { |
| 30 | if (!starts_with_cpu(line)) { |
| 31 | if (proc_nr >= 0) |
| 32 | break; /* we are past "cpuN..." lines */ |
| 33 | continue; |
| 34 | } |
| 35 | if (line[3] != ' ') { /* "cpuN" */ |
| 36 | int num_proc; |
| 37 | if (sscanf(line + 3, "%u", &num_proc) == 1 |
| 38 | && num_proc > proc_nr |
| 39 | ) { |
| 40 | proc_nr = num_proc; |
| 41 | } |
| 42 | } |
| 43 | } |
| 44 | |
| 45 | fclose(fp); |
| 46 | return proc_nr + 1; |
| 47 | } |