2010-08-16 00:49:21 +00:00
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/* vi: set sw=4 ts=4: */
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/*
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* Factored out of mpstat/iostat.
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*
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* Copyright (C) 2010 Marek Polacek <mmpolacek@gmail.com>
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*
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2010-08-16 18:14:46 +00:00
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* Licensed under GPLv2, see file LICENSE in this source tree.
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2010-08-16 00:49:21 +00:00
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*/
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#include "libbb.h"
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/* Does str start with "cpu"? */
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int FAST_FUNC starts_with_cpu(const char *str)
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{
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return ((str[0] - 'c') | (str[1] - 'p') | (str[2] - 'u')) == 0;
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}
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/*
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* Get number of processors. Uses /proc/stat.
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* Return value 0 means one CPU and non SMP kernel.
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* Otherwise N means N processor(s) and SMP kernel.
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*/
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unsigned FAST_FUNC get_cpu_count(void)
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{
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FILE *fp;
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char line[256];
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int proc_nr = -1;
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fp = xfopen_for_read("/proc/stat");
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while (fgets(line, sizeof(line), fp)) {
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if (!starts_with_cpu(line)) {
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if (proc_nr >= 0)
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break; /* we are past "cpuN..." lines */
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continue;
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}
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if (line[3] != ' ') { /* "cpuN" */
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int num_proc;
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if (sscanf(line + 3, "%u", &num_proc) == 1
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&& num_proc > proc_nr
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) {
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proc_nr = num_proc;
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}
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}
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}
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fclose(fp);
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return proc_nr + 1;
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}
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