57 lines
1.6 KiB
C
57 lines
1.6 KiB
C
|
|
||
|
|
#include <sys/types.h>
|
||
|
|
#include <stdlib.h>
|
||
|
|
#include <unistd.h>
|
||
|
|
#include <lib.h>
|
||
|
|
|
||
|
|
/* Retrieve system load average information. */
|
||
|
|
int getloadavg(double *loadavg, int nelem)
|
||
|
|
{
|
||
|
|
struct loadinfo loadinfo;
|
||
|
|
int h, p, unfilled_ticks;
|
||
|
|
#define PERIODS 3
|
||
|
|
int minutes[3] = { 1, 5, 15 };
|
||
|
|
if(nelem < 1) {
|
||
|
|
errno = ENOSPC;
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
|
||
|
|
if(getsysinfo(PM_PROC_NR, SI_LOADINFO, &loadinfo) < 0)
|
||
|
|
return -1;
|
||
|
|
if(nelem > PERIODS)
|
||
|
|
nelem = PERIODS;
|
||
|
|
|
||
|
|
/* How many ticks are missing from the newest-filled slot? */
|
||
|
|
#define TICKSPERSLOT (_LOAD_UNIT_SECS * HZ)
|
||
|
|
unfilled_ticks = TICKSPERSLOT - (loadinfo.last_clock % TICKSPERSLOT);
|
||
|
|
|
||
|
|
for(p = 0; p < nelem; p++) {
|
||
|
|
int h, offset, slots;
|
||
|
|
double l = 0.0;
|
||
|
|
int latest = loadinfo.proc_last_slot;
|
||
|
|
slots = minutes[p] * 60 / _LOAD_UNIT_SECS;
|
||
|
|
|
||
|
|
/* 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++) {
|
||
|
|
int slot;
|
||
|
|
slot = (latest - h + _LOAD_HISTORY) % _LOAD_HISTORY;
|
||
|
|
l += (double) 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] = l / (slots * TICKSPERSLOT - unfilled_ticks);
|
||
|
|
}
|
||
|
|
|
||
|
|
return nelem;
|
||
|
|
}
|
||
|
|
|