66 lines
1.7 KiB
C
66 lines
1.7 KiB
C
/* ProcFS - util.c - utility functions */
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#include "inc.h"
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/*
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* Retrieve system load average information.
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*/
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int
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procfs_getloadavg(struct load * loadavg, int nelem)
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{
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struct loadinfo loadinfo;
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u32_t system_hz, ticks_per_slot;
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int p, unfilled_ticks;
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int h, slots, latest, slot;
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int minutes[3] = { 1, 5, 15 };
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ssize_t l;
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if (nelem < 1) {
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errno = ENOSPC;
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return -1;
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}
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system_hz = sys_hz();
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if ((l = sys_getloadinfo(&loadinfo)) != OK)
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return -1;
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if (nelem > 3)
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nelem = 3;
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/* How many ticks are missing from the newest-filled slot? */
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ticks_per_slot = _LOAD_UNIT_SECS * system_hz;
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unfilled_ticks =
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ticks_per_slot - (loadinfo.last_clock % ticks_per_slot);
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for (p = 0; p < nelem; p++) {
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latest = loadinfo.proc_last_slot;
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slots = minutes[p] * 60 / _LOAD_UNIT_SECS;
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loadavg[p].proc_load = 0;
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/*
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* Add up the total number of process ticks for this number
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* of minutes (minutes[p]). Start with the newest slot, which
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* is latest, and count back for the number of slots that
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* correspond to the right number of minutes. Take wraparound
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* into account by calculating the index modulo _LOAD_HISTORY,
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* which is the number of slots of history kept.
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*/
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for (h = 0; h < slots; h++) {
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slot = (latest - h + _LOAD_HISTORY) % _LOAD_HISTORY;
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loadavg[p].proc_load +=
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loadinfo.proc_load_history[slot];
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l += (ssize_t) loadinfo.proc_load_history[slot];
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}
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/*
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* The load average over this number of minutes is the number
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* of process-ticks divided by the number of ticks, not
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* counting the number of ticks the last slot hasn't been
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* around yet.
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*/
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loadavg[p].ticks = slots * ticks_per_slot - unfilled_ticks;
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}
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return nelem;
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}
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