| /* vi: set sw=4 ts=4: */ |
| /* |
| * Factored out of mpstat/iostat. |
| * |
| * Copyright (C) 2010 Marek Polacek <mmpolacek@gmail.com> |
| * |
| * Licensed under GPLv2, see file LICENSE in this tarball for details. |
| */ |
| #include "libbb.h" |
| |
| /* Does str start with "cpu"? */ |
| int FAST_FUNC starts_with_cpu(const char *str) |
| { |
| return ((str[0] - 'c') | (str[1] - 'p') | (str[2] - 'u')) == 0; |
| } |
| |
| /* |
| * Get number of processors. Uses /proc/stat. |
| * Return value 0 means one CPU and non SMP kernel. |
| * Otherwise N means N processor(s) and SMP kernel. |
| */ |
| unsigned FAST_FUNC get_cpu_count(void) |
| { |
| FILE *fp; |
| char line[256]; |
| int proc_nr = -1; |
| |
| fp = xfopen_for_read("/proc/stat"); |
| while (fgets(line, sizeof(line), fp)) { |
| if (!starts_with_cpu(line)) { |
| if (proc_nr >= 0) |
| break; /* we are past "cpuN..." lines */ |
| continue; |
| } |
| if (line[3] != ' ') { /* "cpuN" */ |
| int num_proc; |
| if (sscanf(line + 3, "%u", &num_proc) == 1 |
| && num_proc > proc_nr |
| ) { |
| proc_nr = num_proc; |
| } |
| } |
| } |
| |
| fclose(fp); |
| return proc_nr + 1; |
| } |