-------------
case PROC_LOADAVG:
return get_loadavg(page);
.....
static int get_loadavg(char * buffer)
{
int a, b, c;
a = avenrun[0] + (FIXED_1/200);
b = avenrun[1] + (FIXED_1/200);
c = avenrun[2] + (FIXED_1/200);
return sprintf(buffer,"%d.%02d %d.%02d %d.%02d %d/%d %d\n",
LOAD_INT(a), LOAD_FRAC(a),
LOAD_INT(b), LOAD_FRAC(b),
LOAD_INT(c), LOAD_FRAC(c),
nr_running, nr_tasks, last_pid);
}
-------------
Ok, das Format aus dem sprintf entspricht genaud dem von /proc/loadavg und
avenrun findet man (den find schreib ich nimmer hin) im Schduler
/usr/src/linux/kernel/sched.c (naja, haette man sich auch denken können)
-------------
/*
* Hmm.. Changed this, as the GNU make sources (load.c) seems to
* imply that avenrun[] is the standard name for this kind of thing.
* Nothing else seems to be standardized: the fractional size etc
* all seem to differ on different machines.
*/
unsigned long avenrun[3] = { 0,0,0 };
/*
* Nr of active tasks - counted in fixed-point numbers
*/
static unsigned long count_active_tasks(void)
{
struct task_struct *p;
unsigned long nr = 0;
read_lock(&tasklist_lock);
for_each_task(p) {
if ((p->state == TASK_RUNNING ||
p->state == TASK_UNINTERRUPTIBLE ||
p->state == TASK_SWAPPING))
nr += FIXED_1;
}
read_unlock(&tasklist_lock);
return nr;
}
static inline void calc_load(unsigned long ticks)
{
unsigned long active_tasks; /* fixed-point */
static int count = LOAD_FREQ;
count -= ticks;
if (count < 0) {
count += LOAD_FREQ;
active_tasks = count_active_tasks();
CALC_LOAD(avenrun[0], EXP_1, active_tasks);
CALC_LOAD(avenrun[1], EXP_5, active_tasks);
CALC_LOAD(avenrun[2], EXP_15, active_tasks);
}
}
-------------
und endlich in /usr/src/linux/include/linux/sched.h:
-------------
/*
* These are the constant used to fake the fixed-point load-average
* counting. Some notes:
* - 11 bit fractions expand to 22 bits by the multiplies: this gives
* a load-average precision of 10 bits integer + 11 bits fractional
* - if you want to count load-averages more often, you need more
* precision, or rounding will get you. With 2-second counting freq,
* the EXP_n values would be 1981, 2034 and 2043 if still using only
* 11 bit fractions.
*/
extern unsigned long avenrun[]; /* Load averages */
#define FSHIFT 11 /* nr of bits of precision */
#define FIXED_1 (1<<FSHIFT) /* 1.0 as fixed-point */
#define LOAD_FREQ (5*HZ) /* 5 sec intervals */
#define EXP_1 1884 /* 1/exp(5sec/1min) as fixed-point */
#define EXP_5 2014 /* 1/exp(5sec/5min) */
#define EXP_15 2037 /* 1/exp(5sec/15min) */
#define CALC_LOAD(load,exp,n) \
load *= exp; \
load += n*(FIXED_1-exp); \
load >>= FSHIFT;
-------------
Hmmm. Sieht so aus, als sei der Load die Anzahl der Prozesse, die
durchschnittlich in den letzten N Minuten auf dem Prozessor gleichzeitig
aktiv waren.
klaus
--
Klaus Muth privat monty@unitopia.de
geschaeftlich muth@hagos.de
----------------------------------------------------------------------
telnet:unitopia.de http://unitopia.de/~monty