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Annotation of Gnu-Mach/kern/mach_factor.c, revision 1.1.1.2

1.1.1.2 ! root        1: /*
1.1       root        2:  * Mach Operating System
                      3:  * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
                      4:  * All Rights Reserved.
1.1.1.2 ! root        5:  *
1.1       root        6:  * Permission to use, copy, modify and distribute this software and its
                      7:  * documentation is hereby granted, provided that both the copyright
                      8:  * notice and this permission notice appear in all copies of the
                      9:  * software, derivative works or modified versions, and any portions
                     10:  * thereof, and that both notices appear in supporting documentation.
1.1.1.2 ! root       11:  *
1.1       root       12:  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
                     13:  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
                     14:  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
1.1.1.2 ! root       15:  *
1.1       root       16:  * Carnegie Mellon requests users of this software to return to
1.1.1.2 ! root       17:  *
1.1       root       18:  *  Software Distribution Coordinator  or  [email protected]
                     19:  *  School of Computer Science
                     20:  *  Carnegie Mellon University
                     21:  *  Pittsburgh PA 15213-3890
1.1.1.2 ! root       22:  *
1.1       root       23:  * any improvements or extensions that they make and grant Carnegie Mellon
                     24:  * the rights to redistribute these changes.
                     25:  */
                     26: /*
                     27:  *     File:   kern/mach_factor.c
                     28:  *     Author: Avadis Tevanian, Jr.
                     29:  *     Date:   1986
                     30:  *
                     31:  *     Compute the Mach Factor.
                     32:  */
                     33: 
                     34: #include <cpus.h>
                     35: 
                     36: #include <mach/machine.h>
                     37: #include <mach/processor_info.h>
                     38: #include <kern/sched.h>
                     39: #include <kern/processor.h>
                     40: #include <kern/time_out.h>
                     41: #if    MACH_KERNEL
                     42: #include <mach/kern_return.h>
                     43: #include <mach/port.h>
1.1.1.2 ! root       44: #endif /* MACH_KERNEL */
1.1       root       45: 
                     46: 
                     47: long   avenrun[3] = {0, 0, 0};
                     48: long   mach_factor[3] = {0, 0, 0};
                     49: 
                     50: /*
                     51:  * Values are scaled by LOAD_SCALE, defined in processor_info.h
                     52:  */
                     53: static long    fract[3] = {
                     54:        800,                    /* (4.0/5.0) 5 second average */
                     55:        966,                    /* (29.0/30.0) 30 second average */
                     56:        983,                    /* (59.0/60.) 1 minute average */
                     57: };
                     58: 
                     59: void compute_mach_factor()
                     60: {
                     61:        register processor_set_t        pset;
                     62:        register processor_t            processor;
                     63:        register int            ncpus;
                     64:        register int            nthreads;
                     65:        register long           factor_now;
                     66:        register long           average_now;
                     67:        register long           load_now;
                     68: 
                     69:        simple_lock(&all_psets_lock);
                     70:        pset = (processor_set_t) queue_first(&all_psets);
                     71:        while (!queue_end(&all_psets, (queue_entry_t)pset)) {
                     72: 
                     73:            /*
                     74:             *  If no processors, this pset is in suspended animation.
                     75:             *  No load calculations are performed.
                     76:             */
                     77:            pset_lock(pset);
                     78:            if((ncpus = pset->processor_count) > 0) {
                     79: 
                     80:                /*
                     81:                 *      Count number of threads.
                     82:                 */
                     83:                nthreads = pset->runq.count;
                     84:                processor = (processor_t) queue_first(&pset->processors);
                     85:                while (!queue_end(&pset->processors,
                     86:                    (queue_entry_t)processor)) {
                     87:                        nthreads += processor->runq.count;
                     88:                        processor =
                     89:                            (processor_t) queue_next(&processor->processors);
                     90:                }
                     91: 
                     92:                /*
                     93:                 * account for threads on cpus.
                     94:                 */
1.1.1.2 ! root       95:                nthreads += ncpus - pset->idle_count;
1.1       root       96: 
                     97:                /*
                     98:                 *      The current thread (running this calculation)
                     99:                 *      doesn't count; it's always in the default pset.
                    100:                 */
                    101:                if (pset == &default_pset)
                    102:                   nthreads -= 1;
                    103: 
                    104:                if (nthreads > ncpus) {
                    105:                        factor_now = (ncpus * LOAD_SCALE) / (nthreads + 1);
                    106:                        load_now = (nthreads << SCHED_SHIFT) / ncpus;
                    107:                }
                    108:                else {
                    109:                        factor_now = (ncpus - nthreads) * LOAD_SCALE;
                    110:                        load_now = SCHED_SCALE;
                    111:                }
                    112: 
                    113:                /*
                    114:                 *      Load average and mach factor calculations for
                    115:                 *      those that ask about these things.
                    116:                 */
                    117: 
                    118:                average_now = nthreads * LOAD_SCALE;
                    119: 
                    120:                pset->mach_factor =
                    121:                        ((pset->mach_factor << 2) + factor_now)/5;
                    122:                pset->load_average =
                    123:                        ((pset->load_average << 2) + average_now)/5;
                    124: 
                    125:                /*
                    126:                 *      And some ugly stuff to keep w happy.
                    127:                 */
                    128:                if (pset == &default_pset) {
                    129:                    register int i;
                    130: 
                    131:                    for (i = 0; i < 3; i++) {
                    132:                        mach_factor[i] = ( (mach_factor[i]*fract[i])
                    133:                                 + (factor_now*(LOAD_SCALE-fract[i])) )
                    134:                                / LOAD_SCALE;
                    135:                        avenrun[i] = ( (avenrun[i]*fract[i])
                    136:                                 + (average_now*(LOAD_SCALE-fract[i])) )
                    137:                                / LOAD_SCALE;
                    138:                    }
                    139:                }
                    140: 
                    141:                /*
                    142:                 *      sched_load is the only thing used by scheduler.
                    143:                 *      It is always at least 1 (i.e. SCHED_SCALE).
                    144:                 */
                    145:                pset->sched_load = (pset->sched_load + load_now) >> 1;
                    146:            }
                    147: 
                    148:            pset_unlock(pset);
                    149:            pset = (processor_set_t) queue_next(&pset->all_psets);
                    150:        }
                    151: 
                    152:        simple_unlock(&all_psets_lock);
                    153: }

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