src/surf/fair_bottleneck.c

   1 /*      $Id$ */
   2
   3 /* Copyright (c) 2007 Arnaud Legrand. All rights reserved.               */
   4
   5 /* This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the license (GNU LGPL) which comes with this package. */
   7
   8
   9 #include "xbt/sysdep.h"
  10 #include "xbt/log.h"
  11 #include "maxmin_private.h"
  12 #include <stdlib.h>
  13 #include <math.h>
  14
  15 XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(surf_maxmin);
  16
  17 void bottleneck_solve(lmm_system_t sys)
  18 {
  19   lmm_variable_t var = NULL;
  20   lmm_constraint_t cnst = NULL;
  21   lmm_constraint_t useless_cnst = NULL;
  22   s_lmm_constraint_t s_cnst;
  23   lmm_constraint_t cnst_next = NULL;
  24   lmm_element_t elem = NULL;
  25   xbt_swag_t cnst_list = NULL;
  26   xbt_swag_t var_list = NULL;
  27   xbt_swag_t elem_list = NULL;
  28   double min_usage = -1;
  29
  30   static s_xbt_swag_t cnst_to_update;
  31
  32
  33   if (!(sys->modified))
  34     return;
  35
  36   /* Init */
  37   xbt_swag_init(&(cnst_to_update),
  38                 xbt_swag_offset(s_cnst, saturated_constraint_set_hookup));
  39
  40   var_list = &(sys->variable_set);
  41   DEBUG1("Variable set : %d", xbt_swag_size(var_list));
  42   xbt_swag_foreach(var, var_list) {
  43     var->value = 0.0;
  44   }
  45
  46   cnst_list = &(sys->active_constraint_set);
  47   DEBUG1("Active constraints : %d", xbt_swag_size(cnst_list));
  48   xbt_swag_foreach(cnst, cnst_list) {
  49     xbt_swag_insert(cnst, &(sys->saturated_constraint_set));
  50   }
  51   cnst_list = &(sys->saturated_constraint_set);
  52   xbt_swag_foreach(cnst, cnst_list) {
  53     cnst->remaining = cnst->bound;
  54     cnst->usage = 0.0;
  55   }
  56
  57   /*
  58    * Compute Usage and store the variables that reach the maximum.
  59    */
  60   while(1){
  61     DEBUG1("Constraints to process: %d", xbt_swag_size(cnst_list));
  62     xbt_swag_foreach_safe(cnst, cnst_next, cnst_list) {
  63       int nb = 0;
  64       elem_list = &(cnst->element_set);
  65       cnst->usage = 0.0;
  66       if(!cnst->shared) DIE_IMPOSSIBLE;
  67       xbt_swag_foreach(elem, elem_list) {
  68         if(elem->variable->weight <=0) break;
  69         if ((elem->value > 0)) {
  70           nb++;
  71           if(cnst->usage>0)
  72             cnst->usage = MIN(cnst->usage, elem->value / elem->variable->weight);
  73           else
  74             cnst->usage = elem->value / elem->variable->weight;
  75         }
  76         DEBUG2("Constraint Usage %p : %f",cnst,cnst->usage);
  77         //      make_elem_active(elem);
  78       }
  79       cnst->usage = cnst->usage * nb;
  80       /* Saturated constraints update */
  81       if(min_usage<0 || min_usage > cnst->remaining / cnst->usage) {
  82         min_usage = cnst->remaining / cnst->usage;
  83         while ((useless_cnst = xbt_swag_extract(&(cnst_to_update)))) {
  84           xbt_swag_insert_at_head(useless_cnst, cnst_list);
  85         }
  86         xbt_swag_remove(cnst, cnst_list);
  87         xbt_swag_insert(cnst, &(cnst_to_update));
  88       } else if (min_usage == cnst->remaining / cnst->usage) {
  89         xbt_swag_remove(cnst, cnst_list);
  90         xbt_swag_insert(cnst, &(cnst_to_update));
  91       }
  92     }
  93
  94     if(!xbt_swag_size(&cnst_to_update)) break;
  95
  96     while((cnst = xbt_swag_extract(&cnst_to_update))) {
  97       int nb = 0;
  98       xbt_swag_foreach(elem, elem_list) {
  99         if(elem->variable->weight <=0) break;
 100         if ((elem->value > 0)) nb++;
 101       }
 102       xbt_swag_foreach(elem, elem_list) {
 103         var=elem->variable;
 104         if(var->weight <=0) break;
 105         if(var->value == 0.0) {
 106           int i;
 107           var->value = cnst->remaining / nb * var->weight /
 108             elem->value;
 109
 110           /* Update usage */
 111
 112           for (i = 0; i < var->cnsts_number; i++) {
 113             lmm_element_t elm = &var->cnsts[i];
 114             cnst = elm->constraint;
 115               double_update(&(cnst->remaining), elm->value * var->value);
 116               double_update(&(cnst->usage), elm->value / var->weight);
 117               //              make_elem_inactive(elm);
 118             }
 119           }
 120         }
 121     }
 122   }
 123
 124   sys->modified = 0;
 125   if(XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug)) {
 126     lmm_print(sys);
 127   }
 128 }
 129