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_f  = func_f_def;
 180   var->func_fp  = func_fp_def;
 181   var->func_fpi  = func_fpi_def;
 182
 183   if(weight) xbt_swag_insert_at_head(var,&(sys->variable_set));
 184   else xbt_swag_insert_at_tail(var,&(sys->variable_set));
 185   XBT_OUT;
 186   return var;
 187 }
 188
 189 void lmm_variable_free(lmm_system_t sys, lmm_variable_t var)
 190 {
 191   remove_variable(sys, var);
 192   lmm_var_free(sys, var);
 193 }
 194
 195 double lmm_variable_getvalue(lmm_variable_t var)
 196 {
 197   return (var->value);
 198 }
 199
 200 void lmm_expand(lmm_system_t sys, lmm_constraint_t cnst,
 201                 lmm_variable_t var, double value)
 202 {
 203   lmm_element_t elem = NULL;
 204
 205   sys->modified = 1;
 206
 207   xbt_assert0(var->cnsts_number < var->cnsts_size,
 208               "Too much constraints");
 209
 210   elem = &(var->cnsts[var->cnsts_number++]);
 211
 212   elem->value = value;
 213   elem->constraint = cnst;
 214   elem->variable = var;
 215
 216   if(var->weight) xbt_swag_insert_at_head(elem,&(elem->constraint->element_set));
 217   else xbt_swag_insert_at_tail(elem,&(elem->constraint->element_set));
 218
 219   make_constraint_active(sys, cnst);
 220 }
 221
 222 void lmm_expand_add(lmm_system_t sys, lmm_constraint_t cnst,
 223                     lmm_variable_t var, double value)
 224 {
 225   int i ;
 226   sys->modified = 1;
 227
 228   for(i=0; i< var->cnsts_number ; i++)
 229     if(var->cnsts[i].constraint == cnst) break;
 230
 231   if(i<var->cnsts_number) var->cnsts[i].value +=value;
 232   else lmm_expand(sys,cnst,var,value);
 233 }
 234
 235 void lmm_elem_set_value(lmm_system_t sys, lmm_constraint_t cnst,
 236                         lmm_variable_t var, double value)
 237 {
 238   int i ;
 239
 240   for(i=0; i< var->cnsts_number ; i++)
 241     if(var->cnsts[i].constraint == cnst) break;
 242
 243   if(i<var->cnsts_number) {
 244     var->cnsts[i].value =value;
 245     sys->modified = 1;
 246   } else DIE_IMPOSSIBLE;
 247 }
 248
 249 lmm_constraint_t lmm_get_cnst_from_var(lmm_system_t sys,
 250                                        lmm_variable_t var, int num)
 251 {
 252   if (num < var->cnsts_number)
 253     return (var->cnsts[num].constraint);
 254   else
 255     return NULL;
 256 }
 257
 258 int lmm_get_number_of_cnst_from_var(lmm_system_t sys, lmm_variable_t var)
 259 {
 260   return (var->cnsts_number);
 261 }
 262
 263 lmm_variable_t lmm_get_var_from_cnst(lmm_system_t sys,
 264                                      lmm_constraint_t cnst,
 265                                      lmm_variable_t * var)
 266 {
 267   if (!(*var))
 268     xbt_swag_getFirst(&(cnst->element_set));
 269   else
 270     *var = xbt_swag_getNext(*var, cnst->element_set.offset);
 271   return *var;
 272 }
 273
 274 void *lmm_constraint_id(lmm_constraint_t cnst)
 275 {
 276   return cnst->id;
 277 }
 278
 279 void *lmm_variable_id(lmm_variable_t var)
 280 {
 281   return var->id;
 282 }
 283
 284 static void saturated_constraint_set_update(lmm_system_t sys,
 285                                             lmm_constraint_t cnst,
 286                                             double *min_usage)
 287 {
 288   lmm_constraint_t useless_cnst = NULL;
 289
 290   XBT_IN3("sys=%p, cnst=%p, min_usage=%f",sys,cnst,*min_usage);
 291   if (cnst->usage <= 0) {
 292     XBT_OUT;
 293     return;
 294   }
 295   if (cnst->remaining <= 0) {
 296     XBT_OUT;
 297     return;
 298   }
 299   if ((*min_usage < 0) || (*min_usage > cnst->remaining / cnst->usage)) {
 300     *min_usage = cnst->remaining / cnst->usage;
 301     LOG3(xbt_log_priority_trace,
 302          "min_usage=%f (cnst->remaining=%f, cnst->usage=%f)",*min_usage,
 303          cnst->remaining, cnst->usage);
 304     while ((useless_cnst =
 305             xbt_swag_getFirst(&(sys->saturated_constraint_set))))
 306       xbt_swag_remove(useless_cnst, &(sys->saturated_constraint_set));
 307
 308     xbt_swag_insert(cnst, &(sys->saturated_constraint_set));
 309   } else if (*min_usage == cnst->remaining / cnst->usage) {
 310     xbt_swag_insert(cnst, &(sys->saturated_constraint_set));
 311   }
 312   XBT_OUT;
 313 }
 314
 315 static void saturated_variable_set_update(lmm_system_t sys)
 316 {
 317   lmm_constraint_t cnst = NULL;
 318   xbt_swag_t cnst_list = NULL;
 319   lmm_element_t elem = NULL;
 320   xbt_swag_t elem_list = NULL;
 321
 322   cnst_list = &(sys->saturated_constraint_set);
 323   while ((cnst = xbt_swag_getFirst(cnst_list))) {
 324     elem_list = &(cnst->active_element_set);
 325     xbt_swag_foreach(elem, elem_list) {
 326       if(elem->variable->weight<=0) break;
 327       if ((elem->value > 0))
 328         xbt_swag_insert(elem->variable, &(sys->saturated_variable_set));
 329     }
 330     xbt_swag_remove(cnst, cnst_list);
 331   }
 332 }
 333
 334 void lmm_print(lmm_system_t sys)
 335
 336 {
 337   lmm_constraint_t cnst = NULL;
 338   lmm_element_t elem = NULL;
 339   lmm_variable_t var = NULL;
 340   xbt_swag_t cnst_list = NULL;
 341   xbt_swag_t var_list = NULL;
 342   xbt_swag_t elem_list = NULL;
 343   char print_buf[1024];
 344   char *trace_buf=xbt_malloc0(sizeof(char));
 345   double sum=0.0;
 346
 347   /* Printing Objective */
 348   var_list = &(sys->variable_set);
 349   sprintf(print_buf,"MAX-MIN ( ");
 350   trace_buf = xbt_realloc(trace_buf,strlen(trace_buf)+strlen(print_buf)+1);
 351   strcat(trace_buf, print_buf);
 352   xbt_swag_foreach(var, var_list) {
 353     sprintf(print_buf,"'%p'(%f) ",var,var->weight);
 354     trace_buf = xbt_realloc(trace_buf,strlen(trace_buf)+strlen(print_buf)+1);
 355     strcat(trace_buf, print_buf);
 356   }
 357   sprintf(print_buf,")");
 358   trace_buf = xbt_realloc(trace_buf,strlen(trace_buf)+strlen(print_buf)+1);
 359   strcat(trace_buf, print_buf);
 360   DEBUG1("%s",trace_buf);
 361   trace_buf[0]='\000';
 362
 363   /* Printing Constraints */
 364   cnst_list = &(sys->active_constraint_set);
 365   xbt_swag_foreach(cnst, cnst_list) {
 366     sum=0.0;
 367     elem_list = &(cnst->element_set);
 368     sprintf(print_buf,"\t");
 369     trace_buf = xbt_realloc(trace_buf,strlen(trace_buf)+strlen(print_buf)+1);
 370     strcat(trace_buf, print_buf);
 371     xbt_swag_foreach(elem, elem_list) {
 372       sprintf(print_buf,"%f.'%p'(%f) + ",elem->value,
 373               elem->variable,elem->variable->value);
 374       trace_buf = xbt_realloc(trace_buf,strlen(trace_buf)+strlen(print_buf)+1);
 375       strcat(trace_buf, print_buf);
 376       sum += elem->value * elem->variable->value;
 377     }
 378     sprintf(print_buf,"0 <= %f ('%p')",cnst->bound,cnst);
 379     trace_buf = xbt_realloc(trace_buf,strlen(trace_buf)+strlen(print_buf)+1);
 380     strcat(trace_buf, print_buf);
 381
 382     if(!cnst->shared) {
 383       sprintf(print_buf," [MAX-Constraint]");
 384       trace_buf = xbt_realloc(trace_buf,strlen(trace_buf)+strlen(print_buf)+1);
 385       strcat(trace_buf, print_buf);
 386     }
 387     DEBUG1("%s",trace_buf);
 388     trace_buf[0]='\000';
 389     if(double_positive(sum-cnst->bound))
 390       WARN3("Incorrect value (%f is not smaller than %f): %g",
 391                sum,cnst->bound,sum-cnst->bound);
 392   }
 393
 394   /* Printing Result */
 395   xbt_swag_foreach(var, var_list) {
 396     if(var->bound>0) {
 397       DEBUG4("'%p'(%f) : %f (<=%f)",var,var->weight,var->value, var->bound);
 398       if(double_positive(var->value-var->bound))
 399          WARN2("Incorrect value (%f is not smaller than %f",
 400                   var->value, var->bound);
 401     }
 402     else
 403       DEBUG3("'%p'(%f) : %f",var,var->weight,var->value);
 404   }
 405
 406   free(trace_buf);
 407 }
 408
 409 void lmm_solve(lmm_system_t sys)
 410 {
 411   lmm_variable_t var = NULL;
 412   lmm_constraint_t cnst = NULL;
 413   lmm_element_t elem = NULL;
 414   xbt_swag_t cnst_list = NULL;
 415   xbt_swag_t var_list = NULL;
 416   xbt_swag_t elem_list = NULL;
 417   double min_usage = -1;
 418
 419   if (!(sys->modified))
 420     return;
 421
 422   /* Init */
 423   var_list = &(sys->variable_set);
 424   DEBUG1("Variable set : %d", xbt_swag_size(var_list));
 425   xbt_swag_foreach(var, var_list) {
 426     var->value = 0.0;
 427   }
 428
 429   /*
 430    * Compute Usage and store the variables that reach the maximum.
 431    */
 432   cnst_list = &(sys->active_constraint_set);
 433   DEBUG1("Active constraints : %d", xbt_swag_size(cnst_list));
 434   xbt_swag_foreach(cnst, cnst_list) {
 435     /* INIT */
 436     cnst->remaining = cnst->bound;
 437     cnst->usage = 0;
 438     elem_list = &(cnst->element_set);
 439     cnst->usage = 0.0;
 440     xbt_swag_foreach(elem, elem_list) {
 441       if(elem->variable->weight <=0) break;
 442       if ((elem->value > 0)) {
 443         if(cnst->shared)
 444           cnst->usage += elem->value / elem->variable->weight;
 445         else
 446           if(cnst->usage<elem->value / elem->variable->weight)
 447             cnst->usage = elem->value / elem->variable->weight;
 448         DEBUG2("Constraint Usage %p : %f",cnst,cnst->usage);
 449         make_elem_active(elem);
 450       }
 451     }
 452     /* Saturated constraints update */
 453     saturated_constraint_set_update(sys, cnst, &min_usage);
 454   }
 455   saturated_variable_set_update(sys);
 456
 457   /* Saturated variables update */
 458
 459   do {
 460     /* Fix the variables that have to be */
 461     var_list = &(sys->saturated_variable_set);
 462
 463     xbt_swag_foreach(var, var_list) {
 464       /* First check if some of these variables have reach their upper
 465          bound and update min_usage accordingly. */
 466       DEBUG5("var=%p, var->bound=%f, var->weight=%f, min_usage=%f, var->bound*var->weight=%f",
 467              var, var->bound, var->weight, min_usage,var->bound * var->weight);
 468       if ((var->bound > 0) && (var->bound * var->weight < min_usage)) {
 469         min_usage = var->bound * var->weight;
 470         DEBUG1("Updated min_usage=%f",min_usage);
 471       }
 472     }
 473
 474
 475     while ((var = xbt_swag_getFirst(var_list))) {
 476       int i;
 477
 478       var->value = min_usage / var->weight;
 479       DEBUG5("Min usage: %f, Var(%p)->weight: %f, Var(%p)->value: %f ",min_usage,var,var->weight,var,var->value);
 480
 481
 482       /* Update usage */
 483
 484       for (i = 0; i < var->cnsts_number; i++) {
 485         elem = &var->cnsts[i];
 486         cnst = elem->constraint;
 487         if(cnst->shared) {
 488           double_update(&(cnst->remaining), elem->value * var->value);
 489           double_update(&(cnst->usage), elem->value / var->weight);
 490           make_elem_inactive(elem);
 491         } else { /* FIXME one day: We recompute usage.... :( */
 492           cnst->usage = 0.0;
 493           make_elem_inactive(elem);
 494           xbt_swag_foreach(elem, elem_list) {
 495             if(elem->variable->weight <=0) break;
 496             if(elem->variable->value > 0) break;
 497             if ((elem->value > 0)) {
 498               if(cnst->usage<elem->value / elem->variable->weight)
 499                 cnst->usage = elem->value / elem->variable->weight;
 500               DEBUG2("Constraint Usage %p : %f",cnst,cnst->usage);
 501               make_elem_active(elem);
 502             }
 503           }
 504         }
 505       }
 506       xbt_swag_remove(var, var_list);
 507     }
 508
 509     /* Find out which variables reach the maximum */
 510     cnst_list = &(sys->active_constraint_set);
 511     min_usage = -1;
 512     xbt_swag_foreach(cnst, cnst_list) {
 513       saturated_constraint_set_update(sys, cnst, &min_usage);
 514     }
 515     saturated_variable_set_update(sys);
 516
 517   } while (xbt_swag_size(&(sys->saturated_variable_set)));
 518
 519   sys->modified = 0;
 520   if(XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug)) {
 521     lmm_print(sys);
 522   }
 523 }
 524
 525 /* Not a O(1) function */
 526
 527 void lmm_update(lmm_system_t sys, lmm_constraint_t cnst,
 528                 lmm_variable_t var, double value)
 529 {
 530   int i;
 531
 532   sys->modified = 1;
 533   for (i = 0; i < var->cnsts_number; i++)
 534     if (var->cnsts[i].constraint == cnst) {
 535       var->cnsts[i].value = value;
 536       return;
 537     }
 538 }
 539
 540 /** \brief Attribute the value bound to var->bound.
 541  *
 542  *  \param sys the lmm_system_t
 543  *  \param var the lmm_variable_t
 544  *  \param bound the new bound to associate with var
 545  *
 546  *  Makes var->bound equal to bound. Whenever this function is called
 547  *  a change is  signed in the system. To
 548  *  avoid false system changing detection it is a good idea to test
 549  *  (bound != 0) before calling it.
 550  *
 551  */
 552 void lmm_update_variable_bound(lmm_system_t sys, lmm_variable_t var,
 553                                double bound)
 554 {
 555   sys->modified = 1;
 556   var->bound = bound;
 557 }
 558
 559 /** \brief Add the value delta to var->df (the sum of latencies).
 560  *
 561  *  \param sys the lmm_system_t associated
 562  *  \param var the lmm_variable_t which need to updated
 563  *  \param delta the variation of the latency
 564  *
 565  *  Add the value delta to var->df (the sum of latencys associated to the
 566  *  flow). Whenever this function is called a change is  signed in the system. To
 567  *  avoid false system changing detection it is a good idea to test
 568  *  (delta != 0) before calling it.
 569  *
 570  */
 571 void lmm_update_variable_latency(lmm_system_t sys, lmm_variable_t var,
 572                                double delta)
 573 {
 574   sys->modified = 1;
 575   var->df += delta;
 576 }
 577
 578 void lmm_update_variable_weight(lmm_system_t sys, lmm_variable_t var,
 579                                 double weight)
 580 {
 581   int i ;
 582   lmm_element_t elem;
 583
 584   XBT_IN3("(sys=%p, var=%p, weight=%f)",sys,var,weight);
 585   sys->modified = 1;
 586   var->weight = weight;
 587   xbt_swag_remove(var,&(sys->variable_set));
 588   if(weight) xbt_swag_insert_at_head(var,&(sys->variable_set));
 589   else xbt_swag_insert_at_tail(var,&(sys->variable_set));
 590
 591   for (i = 0; i < var->cnsts_number; i++) {
 592     elem = &var->cnsts[i];
 593     xbt_swag_remove(elem, &(elem->constraint->element_set));
 594     if(weight) xbt_swag_insert_at_head(elem, &(elem->constraint->element_set));
 595     else xbt_swag_insert_at_tail(elem, &(elem->constraint->element_set));
 596   }
 597   XBT_OUT;
 598 }
 599
 600 double lmm_get_variable_weight(lmm_variable_t var)
 601
 602 {
 603   return var->weight;
 604 }
 605
 606 void lmm_update_constraint_bound(lmm_system_t sys, lmm_constraint_t cnst,
 607                                  double bound)
 608 {
 609   sys->modified = 1;
 610   cnst->bound = bound;
 611 }
 612
 613 int lmm_constraint_used(lmm_system_t sys, lmm_constraint_t cnst)
 614 {
 615   return xbt_swag_belongs(cnst, &(sys->active_constraint_set));
 616 }
 617
 618 lmm_constraint_t lmm_get_first_active_constraint(lmm_system_t sys)
 619 {
 620   return xbt_swag_getFirst(&(sys->active_constraint_set));
 621 }
 622
 623 lmm_constraint_t lmm_get_next_active_constraint(lmm_system_t sys, lmm_constraint_t cnst)
 624 {
 625   return xbt_swag_getNext(cnst,(sys->active_constraint_set).offset);
 626 }
 627
 628