71 lines
1.9 KiB
C
71 lines
1.9 KiB
C
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#include <sys/types.h>
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#include <minix/sysinfo.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <lib.h>
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/* Retrieve system load average information. */
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int getloadavg(double *loadavg, int nelem)
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{
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struct loadinfo loadinfo;
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static u32_t system_hz = 0;
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int h, p, unfilled_ticks;
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#define PERIODS 3
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int minutes[3] = { 1, 5, 15 };
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size_t loadsize;
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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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if(system_hz == 0) {
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if((getsysinfo_up(PM_PROC_NR, SIU_SYSTEMHZ,
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sizeof(system_hz), &system_hz)) < 0) {
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system_hz = DEFAULT_HZ;
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}
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}
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loadsize = sizeof(loadinfo);
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if((l=getsysinfo_up(PM_PROC_NR, SIU_LOADINFO, loadsize, &loadinfo)) < 0)
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return -1;
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if(l != sizeof(loadinfo))
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return -1;
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if(nelem > PERIODS)
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nelem = PERIODS;
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/* How many ticks are missing from the newest-filled slot? */
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#define TICKSPERSLOT (_LOAD_UNIT_SECS * system_hz)
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unfilled_ticks = TICKSPERSLOT - (loadinfo.last_clock % TICKSPERSLOT);
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for(p = 0; p < nelem; p++) {
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int h, offset, slots;
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double l = 0.0;
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int latest = loadinfo.proc_last_slot;
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slots = minutes[p] * 60 / _LOAD_UNIT_SECS;
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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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int slot;
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slot = (latest - h + _LOAD_HISTORY) % _LOAD_HISTORY;
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l += (double) loadinfo.proc_load_history[slot];
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}
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/* The load average over this number of minutes is the number of
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* process-ticks divided by the number of ticks, not counting the
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* number of ticks the last slot hasn't been around yet.
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*/
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loadavg[p] = l / (slots * TICKSPERSLOT - unfilled_ticks);
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}
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return nelem;
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}
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