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