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/*
* Mach Operating System
* Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
* All Rights Reserved.
*
* Permission to use, copy, modify and distribute this software and its
* documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie Mellon
* the rights to redistribute these changes.
*/
/*
* File: kern/mach_factor.c
* Author: Avadis Tevanian, Jr.
* Date: 1986
*
* Compute the Mach Factor.
*/
#include <mach/machine.h>
#include <mach/processor_info.h>
#include <kern/mach_clock.h>
#include <kern/sched.h>
#include <kern/processor.h>
#include <mach/kern_return.h>
#include <mach/port.h>
#include "mach_factor.h"
long avenrun[3] = {0, 0, 0};
long mach_factor[3] = {0, 0, 0};
/*
* Values are scaled by LOAD_SCALE, defined in processor_info.h
*/
static long fract[3] = {
800, /* (4.0/5.0) 5 second average */
966, /* (29.0/30.0) 30 second average */
983, /* (59.0/60.) 1 minute average */
};
void compute_mach_factor(void)
{
processor_set_t pset;
processor_t processor;
int ncpus;
int nthreads;
long factor_now;
long average_now;
long load_now;
simple_lock(&all_psets_lock);
pset = (processor_set_t) queue_first(&all_psets);
while (!queue_end(&all_psets, (queue_entry_t)pset)) {
/*
* If no processors, this pset is in suspended animation.
* No load calculations are performed.
*/
pset_lock(pset);
if((ncpus = pset->processor_count) > 0) {
/*
* Count number of threads.
*/
nthreads = pset->runq.count;
processor = (processor_t) queue_first(&pset->processors);
while (!queue_end(&pset->processors,
(queue_entry_t)processor)) {
nthreads += processor->runq.count;
processor =
(processor_t) queue_next(&processor->processors);
}
/*
* account for threads on cpus.
*/
nthreads += ncpus - pset->idle_count;
/*
* The current thread (running this calculation)
* doesn't count; it's always in the default pset.
*/
if (pset == &default_pset)
nthreads -= 1;
if (nthreads > ncpus) {
factor_now = (ncpus * LOAD_SCALE) / (nthreads + 1);
load_now = (nthreads << SCHED_SHIFT) / ncpus;
}
else {
factor_now = (ncpus - nthreads) * LOAD_SCALE;
load_now = SCHED_SCALE;
}
/*
* Load average and mach factor calculations for
* those that ask about these things.
*/
average_now = nthreads * LOAD_SCALE;
pset->mach_factor =
((pset->mach_factor << 2) + factor_now)/5;
pset->load_average =
((pset->load_average << 2) + average_now)/5;
/*
* And some ugly stuff to keep w happy.
*/
if (pset == &default_pset) {
int i;
for (i = 0; i < 3; i++) {
mach_factor[i] = ( (mach_factor[i]*fract[i])
+ (factor_now*(LOAD_SCALE-fract[i])) )
/ LOAD_SCALE;
avenrun[i] = ( (avenrun[i]*fract[i])
+ (average_now*(LOAD_SCALE-fract[i])) )
/ LOAD_SCALE;
}
}
/*
* sched_load is the only thing used by scheduler.
* It is always at least 1 (i.e. SCHED_SCALE).
*/
pset->sched_load = (pset->sched_load + load_now) >> 1;
}
pset_unlock(pset);
pset = (processor_set_t) queue_next(&pset->all_psets);
}
simple_unlock(&all_psets_lock);
}
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