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load average measurement implementation, accessable through

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getloadavg() system call in the library.
This commit is contained in:
Ben Gras
2005-11-14 15:50:46 +00:00
parent aabef59faa
commit 87f2236ad2
7 changed files with 59 additions and 0 deletions
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31
kernel/clock.c
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@@ -38,6 +38,7 @@
FORWARD _PROTOTYPE( void init_clock, (void) );
FORWARD _PROTOTYPE( int clock_handler, (irq_hook_t *hook) );
FORWARD _PROTOTYPE( int do_clocktick, (message *m_ptr) );
FORWARD _PROTOTYPE( void load_update, (void));
/* Clock parameters. */
#define COUNTER_FREQ (2*TIMER_FREQ) /* counter frequency using square wave */
@@ -205,6 +206,9 @@ irq_hook_t *hook;
bill_ptr->p_ticks_left -= ticks;
}
/* Update load average. */
load_update();
/* Check if do_clocktick() must be called. Done for alarms and scheduling.
* Some processes, such as the kernel tasks, cannot be preempted.
*/
@@ -272,3 +276,30 @@ PUBLIC unsigned long read_clock()
return count;
}
/*===========================================================================*
* load_update *
*===========================================================================*/
PRIVATE void load_update(void)
{
u16_t slot;
/* Load average data is stored as a list of numbers in a circular
* buffer. Each slot accumulates _LOAD_UNIT_SECS of samples of
* the number of runnable processes. Computations can then
* be made of the load average over variable periods, in the
* user library (see getloadavg(3)).
*/
slot = (realtime / HZ / _LOAD_UNIT_SECS) % _LOAD_HISTORY;
if(slot != kloadinfo.proc_last_slot) {
kloadinfo.proc_load_history[slot] = 0;
kloadinfo.proc_last_slot = slot;
}
/* Cumulation. */
kloadinfo.proc_load_history[slot] += kloadinfo.procs_enqueued;
/* Up-to-dateness. */
kloadinfo.last_clock = realtime;
}