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   if (!(sys->modified))
  33     return;
  34
  35   /* Init */
  36   xbt_swag_init(&(cnst_to_update),
  37                 xbt_swag_offset(s_cnst, saturated_constraint_set_hookup));
  38
  39   var_list = &(sys->variable_set);
  40   DEBUG1("Variable set : %d", xbt_swag_size(var_list));
  41   xbt_swag_foreach(var, var_list) {
  42     var->value = 0.0;
  43   }
  44
  45   cnst_list = &(sys->active_constraint_set);
  46   DEBUG1("Active constraints : %d", xbt_swag_size(cnst_list));
  47   xbt_swag_foreach(cnst, cnst_list) {
  48     xbt_swag_insert(cnst, &(sys->saturated_constraint_set));
  49   }
  50   cnst_list = &(sys->saturated_constraint_set);
  51   xbt_swag_foreach(cnst, cnst_list) {
  52     cnst->remaining = cnst->bound;
  53     cnst->usage = 0.0;
  54   }
  55
  56   /*
  57    * Compute Usage and store the variables that reach the maximum.
  58    */
  59   while(1){
  60     DEBUG1("Constraints to process: %d", xbt_swag_size(cnst_list));
  61     xbt_swag_foreach_safe(cnst, cnst_next, cnst_list) {
  62       int nb = 0;
  63       elem_list = &(cnst->element_set);
  64       cnst->usage = 0.0;
  65       xbt_swag_foreach(elem, elem_list) {
  66         if(elem->variable->weight <=0) break;
  67         if ((elem->value > 0)) {
  68           nb++;
  69           if(cnst->usage>0)
  70             cnst->usage = MIN(cnst->usage, elem->value / elem->variable->weight);
  71           else
  72             cnst->usage = elem->value / elem->variable->weight;
  73         }
  74         DEBUG2("Constraint Usage %p : %f",cnst,cnst->usage);
  75         //      make_elem_active(elem);
  76       }
  77       if(!cnst->shared) nb=1;
  78       cnst->usage = cnst->usage * nb;
  79       /* Saturated constraints update */
  80       if(min_usage<0 || min_usage > cnst->remaining / cnst->usage) {
  81         min_usage = cnst->remaining / cnst->usage;
  82         while ((useless_cnst = xbt_swag_extract(&(cnst_to_update)))) {
  83           xbt_swag_insert_at_head(useless_cnst, cnst_list);
  84         }
  85         xbt_swag_remove(cnst, cnst_list);
  86         xbt_swag_insert(cnst, &(cnst_to_update));
  87       } else if (min_usage == cnst->remaining / cnst->usage) {
  88         xbt_swag_remove(cnst, cnst_list);
  89         xbt_swag_insert(cnst, &(cnst_to_update));
  90       }
  91     }
  92
  93     if(!xbt_swag_size(&cnst_to_update)) break;
  94
  95     while((cnst = xbt_swag_extract(&cnst_to_update))) {
  96       int nb = 0;
  97       xbt_swag_foreach(elem, elem_list) {
  98         if(elem->variable->weight <=0) break;
  99         if ((elem->value > 0)) nb++;
 100       }
 101       if(!cnst->shared) nb=1;
 102
 103       xbt_swag_foreach(elem, elem_list) {
 104         var=elem->variable;
 105         if(var->weight <=0) break;
 106         if(var->value == 0.0) {
 107           int i;
 108           var->value = cnst->remaining / nb * var->weight /
 109             elem->value;
 110
 111           /* Update usage */
 112
 113           for (i = 0; i < var->cnsts_number; i++) {
 114             lmm_element_t elm = &var->cnsts[i];
 115             cnst = elm->constraint;
 116               double_update(&(cnst->remaining), elm->value * var->value);
 117               double_update(&(cnst->usage), elm->value / var->weight);
 118               //              make_elem_inactive(elm);
 119             }
 120           }
 121         }
 122     }
 123   }
 124
 125   sys->modified = 0;
 126   if(XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug)) {
 127     lmm_print(sys);
 128   }
 129 }
 130