src/surf/maxmin.c

   1 /*      $Id$     */
   2
   3 /* Copyright (c) 2004 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 "xbt/mallocator.h"
  12 #include "maxmin_private.h"
  13 #include <stdlib.h>
  14 #include <math.h>
  15 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(surf_maxmin, surf,
  16                                 "Logging specific to SURF (maxmin)");
  17
  18 static void* lmm_variable_mallocator_new_f(void);
  19 static void lmm_variable_mallocator_free_f(void *var);
  20 static void lmm_variable_mallocator_reset_f(void *var);
  21
  22 lmm_system_t lmm_system_new(void)
  23 {
  24   lmm_system_t l = NULL;
  25   s_lmm_variable_t var;
  26   s_lmm_constraint_t cnst;
  27
  28   l = xbt_new0(s_lmm_system_t, 1);
  29
  30   l->modified = 0;
  31   xbt_swag_init(&(l->variable_set),
  32                 xbt_swag_offset(var, variable_set_hookup));
  33   xbt_swag_init(&(l->constraint_set),
  34                 xbt_swag_offset(cnst, constraint_set_hookup));
  35
  36   xbt_swag_init(&(l->active_constraint_set),
  37                 xbt_swag_offset(cnst, active_constraint_set_hookup));
  38
  39   xbt_swag_init(&(l->saturated_variable_set),
  40                 xbt_swag_offset(var, saturated_variable_set_hookup));
  41   xbt_swag_init(&(l->saturated_constraint_set),
  42                 xbt_swag_offset(cnst, saturated_constraint_set_hookup));
  43
  44   l->variable_mallocator = xbt_mallocator_new(64,
  45                                               lmm_variable_mallocator_new_f,
  46                                               lmm_variable_mallocator_free_f,
  47                                               lmm_variable_mallocator_reset_f);
  48
  49   return l;
  50 }
  51
  52 void lmm_system_free(lmm_system_t sys)
  53 {
  54   lmm_variable_t var = NULL;
  55   lmm_constraint_t cnst = NULL;
  56
  57   while ((var = extract_variable(sys)))
  58     lmm_var_free(sys, var);
  59
  60   while ((cnst = extract_constraint(sys)))
  61     lmm_cnst_free(sys, cnst);
  62
  63   xbt_mallocator_free(sys->variable_mallocator);
  64   free(sys);
  65 }
  66
  67 void lmm_variable_disable(lmm_system_t sys, lmm_variable_t var)
  68 {
  69   int i;
  70   lmm_element_t elem = NULL;
  71
  72   XBT_IN2("(sys=%p, var=%p)",sys,var);
  73   sys->modified = 1;
  74
  75   for (i = 0; i < var->cnsts_number; i++) {
  76     elem = &var->cnsts[i];
  77     xbt_swag_remove(elem, &(elem->constraint->element_set));
  78     xbt_swag_remove(elem, &(elem->constraint->active_element_set));
  79     if (!xbt_swag_size(&(elem->constraint->element_set)))
  80       make_constraint_inactive(sys, elem->constraint);
  81   }
  82   var->cnsts_number = 0;
  83   XBT_OUT;
  84 }
  85
  86 static void lmm_var_free(lmm_system_t sys, lmm_variable_t var)
  87 {
  88
  89   lmm_variable_disable(sys, var);
  90   free(var->cnsts);
  91   xbt_mallocator_release(sys->variable_mallocator, var);
  92 }
  93
  94 static void lmm_cnst_free(lmm_system_t sys, lmm_constraint_t cnst)
  95 {
  96 /*   xbt_assert0(xbt_swag_size(&(cnst->element_set)), */
  97 /*            "This list should be empty!"); */
  98   remove_active_constraint(sys, cnst);
  99   free(cnst);
 100 }
 101
 102 lmm_constraint_t lmm_constraint_new(lmm_system_t sys, void *id,
 103                                     double bound_value)
 104 {
 105   lmm_constraint_t cnst = NULL;
 106   s_lmm_element_t elem;
 107
 108   cnst = xbt_new0(s_lmm_constraint_t, 1);
 109   cnst->id = id;
 110   xbt_swag_init(&(cnst->element_set),
 111                 xbt_swag_offset(elem, element_set_hookup));
 112   xbt_swag_init(&(cnst->active_element_set),
 113                 xbt_swag_offset(elem, active_element_set_hookup));
 114
 115   cnst->bound = bound_value;
 116   cnst->usage = 0;
 117   cnst->shared = 1;
 118   insert_constraint(sys, cnst);
 119
 120   return cnst;
 121 }
 122
 123 void lmm_constraint_shared(lmm_constraint_t cnst)
 124 {
 125   cnst->shared = 0;
 126 }
 127
 128 void lmm_constraint_free(lmm_system_t sys, lmm_constraint_t cnst)
 129 {
 130   remove_constraint(sys, cnst);
 131   lmm_cnst_free(sys, cnst);
 132 }
 133
 134 static void* lmm_variable_mallocator_new_f(void) {
 135   return xbt_new(s_lmm_variable_t, 1);
 136 }
 137
 138 static void lmm_variable_mallocator_free_f(void *var) {
 139   xbt_free(var);
 140 }
 141
 142 static void lmm_variable_mallocator_reset_f(void *var) {
 143   /* memset to zero like calloc */
 144   memset(var, 0, sizeof(s_lmm_variable_t));
 145 }
 146
 147 lmm_variable_t lmm_variable_new(lmm_system_t sys, void *id,
 148                                 double weight,
 149                                 double bound, int number_of_constraints)
 150 {
 151   lmm_variable_t var = NULL;
 152   int i;
 153
 154   XBT_IN5("(sys=%p, id=%p, weight=%f, bound=%f, num_cons =%d)",
 155           sys,id,weight,bound,number_of_constraints);
 156
 157   var = xbt_mallocator_get(sys->variable_mallocator);
 158   var->id = id;
 159   var->cnsts = xbt_new0(s_lmm_element_t, number_of_constraints);
 160   for(i=0; i<number_of_constraints; i++) {
 161     /* Should be useless because of the
 162        calloc but it seems to help valgrind... */
 163     var->cnsts[i].element_set_hookup.next = NULL;
 164     var->cnsts[i].element_set_hookup.prev = NULL;
 165     var->cnsts[i].active_element_set_hookup.next = NULL;
 166     var->cnsts[i].active_element_set_hookup.prev = NULL;
 167     var->cnsts[i].constraint = NULL;
 168     var->cnsts[i].variable = NULL;
 169     var->cnsts[i].value = 0.0;
 170   }
 171   var->cnsts_size = number_of_constraints;
 172   var->cnsts_number = 0; /* Should be useless because of the
 173                             calloc but it seems to help valgrind... */
 174   var->weight = weight;
 175   var->bound = bound;
 176   var->value = 0.0;
 177   var->df    = 0.0;
 178
 179   var->func_fpi  = func_fpi_def;
 180
 181   if(weight) xbt_swag_insert_at_head(var,&(sys->variable_set));
 182   else xbt_swag_insert_at_tail(var,&(sys->variable_set));
 183   XBT_OUT;
 184   return var;
 185 }
 186
 187 void lmm_variable_free(lmm_system_t sys, lmm_variable_t var)
 188 {
 189   remove_variable(sys, var);
 190   lmm_var_free(sys, var);
 191 }
 192
 193 double lmm_variable_getvalue(lmm_variable_t var)
 194 {
 195   return (var->value);
 196 }
 197
 198 void lmm_expand(lmm_system_t sys, lmm_constraint_t cnst,
 199                 lmm_variable_t var, double value)
 200 {
 201   lmm_element_t elem = NULL;
 202
 203   sys->modified = 1;
 204
 205   xbt_assert0(var->cnsts_number < var->cnsts_size,
 206               "Too much constraints");
 207
 208   elem = &(var->cnsts[var->cnsts_number++]);
 209
 210   elem->value = value;
 211   elem->constraint = cnst;
 212   elem->variable = var;
 213
 214   if(var->weight) xbt_swag_insert_at_head(elem,&(elem->constraint->element_set));
 215   else xbt_swag_insert_at_tail(elem,&(elem->constraint->element_set));
 216
 217   make_constraint_active(sys, cnst);
 218 }
 219
 220 void lmm_expand_add(lmm_system_t sys, lmm_constraint_t cnst,
 221                     lmm_variable_t var, double value)
 222 {
 223   int i ;
 224   sys->modified = 1;
 225
 226   for(i=0; i< var->cnsts_number ; i++)
 227     if(var->cnsts[i].constraint == cnst) break;
 228
 229   if(i<var->cnsts_number) var->cnsts[i].value +=value;
 230   else lmm_expand(sys,cnst,var,value);
 231 }
 232
 233 void lmm_elem_set_value(lmm_system_t sys, lmm_constraint_t cnst,
 234                         lmm_variable_t var, double value)
 235 {
 236   int i ;
 237
 238   for(i=0; i< var->cnsts_number ; i++)
 239     if(var->cnsts[i].constraint == cnst) break;
 240
 241   if(i<var->cnsts_number) {
 242     var->cnsts[i].value =value;
 243     sys->modified = 1;
 244   } else DIE_IMPOSSIBLE;
 245 }
 246
 247 lmm_constraint_t lmm_get_cnst_from_var(lmm_system_t sys,
 248                                        lmm_variable_t var, int num)
 249 {
 250   if (num < var->cnsts_number)
 251     return (var->cnsts[num].constraint);
 252   else
 253     return NULL;
 254 }
 255
 256 int lmm_get_number_of_cnst_from_var(lmm_system_t sys, lmm_variable_t var)
 257 {
 258   return (var->cnsts_number);
 259 }
 260
 261 lmm_variable_t lmm_get_var_from_cnst(lmm_system_t sys,
 262                                      lmm_constraint_t cnst,
 263                                      lmm_variable_t * var)
 264 {
 265   if (!(*var))
 266     xbt_swag_getFirst(&(cnst->element_set));
 267   else
 268     *var = xbt_swag_getNext(*var, cnst->element_set.offset);
 269   return *var;
 270 }
 271
 272 void *lmm_constraint_id(lmm_constraint_t cnst)
 273 {
 274   return cnst->id;
 275 }
 276
 277 void *lmm_variable_id(lmm_variable_t var)
 278 {
 279   return var->id;
 280 }
 281
 282 static void saturated_constraint_set_update(lmm_system_t sys,
 283                                             lmm_constraint_t cnst,
 284                                             double *min_usage)
 285 {
 286   lmm_constraint_t useless_cnst = NULL;
 287
 288   XBT_IN3("sys=%p, cnst=%p, min_usage=%f",sys,cnst,*min_usage);
 289   if (cnst->usage <= 0) {
 290     XBT_OUT;
 291     return;
 292   }
 293   if (cnst->remaining <= 0) {
 294     XBT_OUT;
 295     return;
 296   }
 297   if ((*min_usage < 0) || (*min_usage > cnst->remaining / cnst->usage)) {
 298     *min_usage = cnst->remaining / cnst->usage;
 299     LOG3(xbt_log_priority_trace,
 300          "min_usage=%f (cnst->remaining=%f, cnst->usage=%f)",*min_usage,
 301          cnst->remaining, cnst->usage);
 302     while ((useless_cnst =
 303             xbt_swag_getFirst(&(sys->saturated_constraint_set))))
 304       xbt_swag_remove(useless_cnst, &(sys->saturated_constraint_set));
 305
 306     xbt_swag_insert(cnst, &(sys->saturated_constraint_set));
 307   } else if (*min_usage == cnst->remaining / cnst->usage) {
 308     xbt_swag_insert(cnst, &(sys->saturated_constraint_set));
 309   }
 310   XBT_OUT;
 311 }
 312
 313 static void saturated_variable_set_update(lmm_system_t sys)
 314 {
 315   lmm_constraint_t cnst = NULL;
 316   xbt_swag_t cnst_list = NULL;
 317   lmm_element_t elem = NULL;
 318   xbt_swag_t elem_list = NULL;
 319
 320   cnst_list = &(sys->saturated_constraint_set);
 321   while ((cnst = xbt_swag_getFirst(cnst_list))) {
 322     elem_list = &(cnst->active_element_set);
 323     xbt_swag_foreach(elem, elem_list) {
 324       if(elem->variable->weight<=0) break;
 325       if ((elem->value > 0))
 326         xbt_swag_insert(elem->variable, &(sys->saturated_variable_set));
 327     }
 328     xbt_swag_remove(cnst, cnst_list);
 329   }
 330 }
 331
 332 void lmm_print(lmm_system_t sys)
 333
 334 {
 335   lmm_constraint_t cnst = NULL;
 336   lmm_element_t elem = NULL;
 337   lmm_variable_t var = NULL;
 338   xbt_swag_t cnst_list = NULL;
 339   xbt_swag_t var_list = NULL;
 340   xbt_swag_t elem_list = NULL;
 341   char print_buf[1024];
 342   char *trace_buf=xbt_malloc0(sizeof(char));
 343   double sum=0.0;
 344
 345   /* Printing Objective */
 346   var_list = &(sys->variable_set);
 347   sprintf(print_buf,"MAX-MIN ( ");
 348   trace_buf = xbt_realloc(trace_buf,strlen(trace_buf)+strlen(print_buf)+1);
 349   strcat(trace_buf, print_buf);
 350   xbt_swag_foreach(var, var_list) {
 351     sprintf(print_buf,"'%p'(%f) ",var,var->weight);
 352     trace_buf = xbt_realloc(trace_buf,strlen(trace_buf)+strlen(print_buf)+1);
 353     strcat(trace_buf, print_buf);
 354   }
 355   sprintf(print_buf,")");
 356   trace_buf = xbt_realloc(trace_buf,strlen(trace_buf)+strlen(print_buf)+1);
 357   strcat(trace_buf, print_buf);
 358   DEBUG1("%s",trace_buf);
 359   trace_buf[0]='\000';
 360
 361   /* Printing Constraints */
 362   cnst_list = &(sys->active_constraint_set);
 363   xbt_swag_foreach(cnst, cnst_list) {
 364     sum=0.0;
 365     elem_list = &(cnst->element_set);
 366     sprintf(print_buf,"\t");
 367     trace_buf = xbt_realloc(trace_buf,strlen(trace_buf)+strlen(print_buf)+1);
 368     strcat(trace_buf, print_buf);
 369     xbt_swag_foreach(elem, elem_list) {
 370       sprintf(print_buf,"%f.'%p'(%f) + ",elem->value,
 371               elem->variable,elem->variable->value);
 372       trace_buf = xbt_realloc(trace_buf,strlen(trace_buf)+strlen(print_buf)+1);
 373       strcat(trace_buf, print_buf);
 374       sum += elem->value * elem->variable->value;
 375     }
 376     sprintf(print_buf,"0 <= %f ('%p')",cnst->bound,cnst);
 377     trace_buf = xbt_realloc(trace_buf,strlen(trace_buf)+strlen(print_buf)+1);
 378     strcat(trace_buf, print_buf);
 379
 380     if(!cnst->shared) {
 381       sprintf(print_buf," [MAX-Constraint]");
 382       trace_buf = xbt_realloc(trace_buf,strlen(trace_buf)+strlen(print_buf)+1);
 383       strcat(trace_buf, print_buf);
 384     }
 385     DEBUG1("%s",trace_buf);
 386     trace_buf[0]='\000';
 387     xbt_assert3(!double_positive(sum-cnst->bound), "Incorrect value (%f is not smaller than %f): %g",
 388                 sum,cnst->bound,sum-cnst->bound);
 389   }
 390
 391   /* Printing Result */
 392   xbt_swag_foreach(var, var_list) {
 393     if(var->bound>0) {
 394       DEBUG4("'%p'(%f) : %f (<=%f)",var,var->weight,var->value, var->bound);
 395       xbt_assert2(!double_positive(var->value-var->bound), "Incorrect value (%f is not smaller than %f",
 396                   var->value, var->bound);
 397     }
 398     else
 399       DEBUG3("'%p'(%f) : %f",var,var->weight,var->value);
 400   }
 401
 402   free(trace_buf);
 403 }
 404
 405 void lmm_solve(lmm_system_t sys)
 406 {
 407   lmm_variable_t var = NULL;
 408   lmm_constraint_t cnst = NULL;
 409   lmm_element_t elem = NULL;
 410   xbt_swag_t cnst_list = NULL;
 411   xbt_swag_t var_list = NULL;
 412   xbt_swag_t elem_list = NULL;
 413   double min_usage = -1;
 414
 415   if (!(sys->modified))
 416     return;
 417
 418   /* Init */
 419   var_list = &(sys->variable_set);
 420   DEBUG1("Variable set : %d", xbt_swag_size(var_list));
 421   xbt_swag_foreach(var, var_list) {
 422     var->value = 0.0;
 423   }
 424
 425   /*
 426    * Compute Usage and store the variables that reach the maximum.
 427    */
 428   cnst_list = &(sys->active_constraint_set);
 429   DEBUG1("Active constraints : %d", xbt_swag_size(cnst_list));
 430   xbt_swag_foreach(cnst, cnst_list) {
 431     /* INIT */
 432     cnst->remaining = cnst->bound;
 433     cnst->usage = 0;
 434     elem_list = &(cnst->element_set);
 435     cnst->usage = 0.0;
 436     xbt_swag_foreach(elem, elem_list) {
 437       if(elem->variable->weight <=0) break;
 438       if ((elem->value > 0)) {
 439         if(cnst->shared)
 440           cnst->usage += elem->value / elem->variable->weight;
 441         else
 442           if(cnst->usage<elem->value / elem->variable->weight)
 443             cnst->usage = elem->value / elem->variable->weight;
 444         DEBUG2("Constraint Usage %p : %f",cnst,cnst->usage);
 445         make_elem_active(elem);
 446       }
 447     }
 448     /* Saturated constraints update */
 449     saturated_constraint_set_update(sys, cnst, &min_usage);
 450   }
 451   saturated_variable_set_update(sys);
 452
 453   /* Saturated variables update */
 454
 455   do {
 456     /* Fix the variables that have to be */
 457     var_list = &(sys->saturated_variable_set);
 458
 459     xbt_swag_foreach(var, var_list) {
 460       /* First check if some of these variables have reach their upper
 461          bound and update min_usage accordingly. */
 462       DEBUG5("var=%p, var->bound=%f, var->weight=%f, min_usage=%f, var->bound*var->weight=%f",
 463              var, var->bound, var->weight, min_usage,var->bound * var->weight);
 464       if ((var->bound > 0) && (var->bound * var->weight < min_usage)) {
 465         min_usage = var->bound * var->weight;
 466         DEBUG1("Updated min_usage=%f",min_usage);
 467       }
 468     }
 469
 470
 471     while ((var = xbt_swag_getFirst(var_list))) {
 472       int i;
 473
 474       var->value = min_usage / var->weight;
 475       DEBUG5("Min usage: %f, Var(%p)->weight: %f, Var(%p)->value: %f ",min_usage,var,var->weight,var,var->value);
 476
 477
 478       /* Update usage */
 479
 480       for (i = 0; i < var->cnsts_number; i++) {
 481         elem = &var->cnsts[i];
 482         cnst = elem->constraint;
 483         if(cnst->shared) {
 484           double_update(&(cnst->remaining), elem->value * var->value);
 485           double_update(&(cnst->usage), elem->value / var->weight);
 486           make_elem_inactive(elem);
 487         } else { /* FIXME one day: We recompute usage.... :( */
 488           cnst->usage = 0.0;
 489           make_elem_inactive(elem);
 490           xbt_swag_foreach(elem, elem_list) {
 491             if(elem->variable->weight <=0) break;
 492             if(elem->variable->value > 0) break;
 493             if ((elem->value > 0)) {
 494               if(cnst->usage<elem->value / elem->variable->weight)
 495                 cnst->usage = elem->value / elem->variable->weight;
 496               DEBUG2("Constraint Usage %p : %f",cnst,cnst->usage);
 497               make_elem_active(elem);
 498             }
 499           }
 500         }
 501       }
 502       xbt_swag_remove(var, var_list);
 503     }
 504
 505     /* Find out which variables reach the maximum */
 506     cnst_list = &(sys->active_constraint_set);
 507     min_usage = -1;
 508     xbt_swag_foreach(cnst, cnst_list) {
 509       saturated_constraint_set_update(sys, cnst, &min_usage);
 510     }
 511     saturated_variable_set_update(sys);
 512
 513   } while (xbt_swag_size(&(sys->saturated_variable_set)));
 514
 515   sys->modified = 0;
 516   if(XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug)) {
 517     lmm_print(sys);
 518   }
 519 }
 520
 521 /* Not a O(1) function */
 522
 523 void lmm_update(lmm_system_t sys, lmm_constraint_t cnst,
 524                 lmm_variable_t var, double value)
 525 {
 526   int i;
 527
 528   sys->modified = 1;
 529   for (i = 0; i < var->cnsts_number; i++)
 530     if (var->cnsts[i].constraint == cnst) {
 531       var->cnsts[i].value = value;
 532       return;
 533     }
 534 }
 535
 536 /** \brief Attribute the value bound to var->bound.
 537  *
 538  *  \param sys the lmm_system_t
 539  *  \param var the lmm_variable_t
 540  *  \param bound the new bound to associate with var
 541  *
 542  *  Makes var->bound equal to bound. Whenever this function is called
 543  *  a change is  signed in the system. To
 544  *  avoid false system changing detection it is a good idea to test
 545  *  (bound != 0) before calling it.
 546  *
 547  */
 548 void lmm_update_variable_bound(lmm_system_t sys, lmm_variable_t var,
 549                                double bound)
 550 {
 551   sys->modified = 1;
 552   var->bound = bound;
 553 }
 554
 555 /** \brief Add the value delta to var->df (the sum of latencies).
 556  *
 557  *  \param sys the lmm_system_t associated
 558  *  \param var the lmm_variable_t which need to updated
 559  *  \param delta the variation of the latency
 560  *
 561  *  Add the value delta to var->df (the sum of latencys associated to the
 562  *  flow). Whenever this function is called a change is  signed in the system. To
 563  *  avoid false system changing detection it is a good idea to test
 564  *  (delta != 0) before calling it.
 565  *
 566  */
 567 void lmm_update_variable_latency(lmm_system_t sys, lmm_variable_t var,
 568                                double delta)
 569 {
 570   sys->modified = 1;
 571   var->df += delta;
 572 }
 573
 574 void lmm_update_variable_weight(lmm_system_t sys, lmm_variable_t var,
 575                                 double weight)
 576 {
 577   int i ;
 578   lmm_element_t elem;
 579
 580   XBT_IN3("(sys=%p, var=%p, weight=%f)",sys,var,weight);
 581   sys->modified = 1;
 582   var->weight = weight;
 583   xbt_swag_remove(var,&(sys->variable_set));
 584   if(weight) xbt_swag_insert_at_head(var,&(sys->variable_set));
 585   else xbt_swag_insert_at_tail(var,&(sys->variable_set));
 586
 587   for (i = 0; i < var->cnsts_number; i++) {
 588     elem = &var->cnsts[i];
 589     xbt_swag_remove(elem, &(elem->constraint->element_set));
 590     if(weight) xbt_swag_insert_at_head(elem, &(elem->constraint->element_set));
 591     else xbt_swag_insert_at_tail(elem, &(elem->constraint->element_set));
 592   }
 593   XBT_OUT;
 594 }
 595
 596 double lmm_get_variable_weight(lmm_variable_t var)
 597
 598 {
 599   return var->weight;
 600 }
 601
 602 void lmm_update_constraint_bound(lmm_system_t sys, lmm_constraint_t cnst,
 603                                  double bound)
 604 {
 605   sys->modified = 1;
 606   cnst->bound = bound;
 607 }
 608
 609 int lmm_constraint_used(lmm_system_t sys, lmm_constraint_t cnst)
 610 {
 611   return xbt_swag_belongs(cnst, &(sys->active_constraint_set));
 612 }
 613
 614 lmm_constraint_t lmm_get_first_active_constraint(lmm_system_t sys)
 615 {
 616   return xbt_swag_getFirst(&(sys->active_constraint_set));
 617 }
 618
 619 lmm_constraint_t lmm_get_next_active_constraint(lmm_system_t sys, lmm_constraint_t cnst)
 620 {
 621   return xbt_swag_getNext(cnst,(sys->active_constraint_set).offset);
 622 }
 623
 624