1 /* Copyright (c) 2004-2017. The SimGrid Team. All rights reserved. */
3 /* This program is free software; you can redistribute it and/or modify it
4 * under the terms of the license (GNU LGPL) which comes with this package. */
6 /* \file callbacks.h */
8 #include "surf/maxmin.hpp"
9 #include "xbt/backtrace.hpp"
11 #include "xbt/mallocator.h"
12 #include "xbt/sysdep.h"
20 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(surf_maxmin, surf, "Logging specific to SURF (maxmin)");
22 double sg_maxmin_precision = 0.00001; /* Change this with --cfg=maxmin/precision:VALUE */
23 double sg_surf_precision = 0.00001; /* Change this with --cfg=surf/precision:VALUE */
24 int sg_concurrency_limit = -1; /* Change this with --cfg=maxmin/concurrency-limit:VALUE */
29 typedef std::vector<int> dyn_light_t;
31 int s_lmm_variable_t::Global_debug_id = 1;
32 int s_lmm_constraint_t::Global_debug_id = 1;
34 int s_lmm_element_t::get_concurrency() const
36 // Ignore element with weight less than one (e.g. cross-traffic)
37 return (consumption_weight >= 1) ? 1 : 0;
38 // There are other alternatives, but they will change the behaviour of the model..
39 // So do not use it unless you want to make a new model.
40 // If you do, remember to change the variables concurrency share to reflect it.
41 // Potential examples are:
42 // return (elem->weight>0)?1:0;//Include element as soon as weight is non-zero
43 // return (int)ceil(elem->weight);//Include element as the rounded-up integer value of the element weight
46 void s_lmm_element_t::decrease_concurrency()
48 xbt_assert(constraint->concurrency_current >= get_concurrency());
49 constraint->concurrency_current -= get_concurrency();
52 void s_lmm_element_t::increase_concurrency()
54 constraint->concurrency_current += get_concurrency();
56 if (constraint->concurrency_current > constraint->concurrency_maximum)
57 constraint->concurrency_maximum = constraint->concurrency_current;
59 xbt_assert(constraint->get_concurrency_limit() < 0 ||
60 constraint->concurrency_current <= constraint->get_concurrency_limit(),
61 "Concurrency limit overflow!");
64 void s_lmm_system_t::check_concurrency()
66 // These checks are very expensive, so do them only if we want to debug SURF LMM
67 if (not XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug))
71 xbt_swag_foreach(cnstIt, &constraint_set)
73 lmm_constraint_t cnst = (lmm_constraint_t)cnstIt;
76 xbt_swag_foreach(elemIt, &(cnst->enabled_element_set))
78 lmm_element_t elem = (lmm_element_t)elemIt;
79 xbt_assert(elem->variable->sharing_weight > 0);
80 concurrency += elem->get_concurrency();
83 xbt_swag_foreach(elemIt, &(cnst->disabled_element_set))
85 lmm_element_t elem = (lmm_element_t)elemIt;
86 // We should have staged variables only if concurrency is reached in some constraint
87 xbt_assert(cnst->get_concurrency_limit() < 0 || elem->variable->staged_weight == 0 ||
88 elem->variable->get_min_concurrency_slack() < elem->variable->concurrency_share,
89 "should not have staged variable!");
92 xbt_assert(cnst->get_concurrency_limit() < 0 || cnst->get_concurrency_limit() >= concurrency,
93 "concurrency check failed!");
94 xbt_assert(cnst->concurrency_current == concurrency, "concurrency_current is out-of-date!");
97 // Check that for each variable, all corresponding elements are in the same state (i.e. same element sets)
99 xbt_swag_foreach(varIt, &variable_set)
101 lmm_variable_t var = (lmm_variable_t)varIt;
103 if (var->cnsts.empty())
106 lmm_element_t elem = &var->cnsts[0];
107 int belong_to_enabled = xbt_swag_belongs(elem, &(elem->constraint->enabled_element_set));
108 int belong_to_disabled = xbt_swag_belongs(elem, &(elem->constraint->disabled_element_set));
109 int belong_to_active = xbt_swag_belongs(elem, &(elem->constraint->active_element_set));
111 for (s_lmm_element_t const& elem : var->cnsts) {
112 xbt_assert(belong_to_enabled == xbt_swag_belongs(&elem, &(elem.constraint->enabled_element_set)),
113 "Variable inconsistency (1): enabled_element_set");
114 xbt_assert(belong_to_disabled == xbt_swag_belongs(&elem, &(elem.constraint->disabled_element_set)),
115 "Variable inconsistency (2): disabled_element_set");
116 xbt_assert(belong_to_active == xbt_swag_belongs(&elem, &(elem.constraint->active_element_set)),
117 "Variable inconsistency (3): active_element_set");
122 void s_lmm_system_t::var_free(lmm_variable_t var)
124 XBT_IN("(sys=%p, var=%p)", this, var);
127 // TODOLATER Can do better than that by leaving only the variable in only one enabled_element_set, call
128 // update_modified_set, and then remove it..
129 if (not var->cnsts.empty())
130 update_modified_set(var->cnsts[0].constraint);
132 for (s_lmm_element_t& elem : var->cnsts) {
133 if (var->sharing_weight > 0)
134 elem.decrease_concurrency();
135 xbt_swag_remove(&elem, &(elem.constraint->enabled_element_set));
136 xbt_swag_remove(&elem, &(elem.constraint->disabled_element_set));
137 xbt_swag_remove(&elem, &(elem.constraint->active_element_set));
138 int nelements = xbt_swag_size(&(elem.constraint->enabled_element_set)) +
139 xbt_swag_size(&(elem.constraint->disabled_element_set));
141 make_constraint_inactive(elem.constraint);
143 on_disabled_var(elem.constraint);
150 xbt_mallocator_release(variable_mallocator, var);
154 s_lmm_system_t::s_lmm_system_t(bool selective_update) : selective_update_active(selective_update)
156 s_lmm_variable_t var;
157 s_lmm_constraint_t cnst;
162 XBT_DEBUG("Setting selective_update_active flag to %d", selective_update_active);
164 xbt_swag_init(&variable_set, xbt_swag_offset(var, variable_set_hookup));
165 xbt_swag_init(&constraint_set, xbt_swag_offset(cnst, constraint_set_hookup));
167 xbt_swag_init(&active_constraint_set, xbt_swag_offset(cnst, active_constraint_set_hookup));
169 xbt_swag_init(&modified_constraint_set, xbt_swag_offset(cnst, modified_constraint_set_hookup));
170 xbt_swag_init(&saturated_variable_set, xbt_swag_offset(var, saturated_variable_set_hookup));
171 xbt_swag_init(&saturated_constraint_set, xbt_swag_offset(cnst, saturated_constraint_set_hookup));
173 keep_track = nullptr;
174 variable_mallocator = xbt_mallocator_new(65536, s_lmm_system_t::variable_mallocator_new_f,
175 s_lmm_system_t::variable_mallocator_free_f, nullptr);
176 solve_fun = &lmm_solve;
179 s_lmm_system_t::~s_lmm_system_t()
182 lmm_constraint_t cnst;
184 while ((var = extract_variable())) {
185 auto demangled = simgrid::xbt::demangle(typeid(*var->id).name());
186 XBT_WARN("Probable bug: a %s variable (#%d) not removed before the LMM system destruction.", demangled.get(),
190 while ((cnst = extract_constraint()))
193 xbt_mallocator_free(variable_mallocator);
196 void s_lmm_system_t::cnst_free(lmm_constraint_t cnst)
198 make_constraint_inactive(cnst);
202 s_lmm_constraint_t::s_lmm_constraint_t(void* id_value, double bound_value) : bound(bound_value), id(id_value)
204 s_lmm_element_t elem;
206 id_int = Global_debug_id++;
207 xbt_swag_init(&enabled_element_set, xbt_swag_offset(elem, enabled_element_set_hookup));
208 xbt_swag_init(&disabled_element_set, xbt_swag_offset(elem, disabled_element_set_hookup));
209 xbt_swag_init(&active_element_set, xbt_swag_offset(elem, active_element_set_hookup));
213 concurrency_limit = sg_concurrency_limit;
214 concurrency_current = 0;
215 concurrency_maximum = 0;
216 sharing_policy = 1; /* FIXME: don't hardcode the value */
220 cnst_light = nullptr;
223 lmm_constraint_t s_lmm_system_t::constraint_new(void* id, double bound_value)
225 lmm_constraint_t cnst = new s_lmm_constraint_t(id, bound_value);
226 insert_constraint(cnst);
230 void* s_lmm_system_t::variable_mallocator_new_f()
232 return new s_lmm_variable_t;
235 void s_lmm_system_t::variable_mallocator_free_f(void* var)
237 delete static_cast<lmm_variable_t>(var);
240 lmm_variable_t s_lmm_system_t::variable_new(simgrid::surf::Action* id, double sharing_weight, double bound,
241 int number_of_constraints)
243 XBT_IN("(sys=%p, id=%p, weight=%f, bound=%f, num_cons =%d)", this, id, sharing_weight, bound, number_of_constraints);
245 lmm_variable_t var = static_cast<lmm_variable_t>(xbt_mallocator_get(variable_mallocator));
246 var->initialize(id, sharing_weight, bound, number_of_constraints, visited_counter - 1);
248 xbt_swag_insert_at_head(var, &variable_set);
250 xbt_swag_insert_at_tail(var, &variable_set);
252 XBT_OUT(" returns %p", var);
256 void s_lmm_system_t::variable_free(lmm_variable_t var)
258 remove_variable(var);
262 void s_lmm_system_t::expand(lmm_constraint_t cnst, lmm_variable_t var, double consumption_weight)
266 // Check if this variable already has an active element in this constraint
267 // If it does, substract it from the required slack
268 int current_share = 0;
269 if (var->concurrency_share > 1) {
270 for (s_lmm_element_t& elem : var->cnsts) {
271 if (elem.constraint == cnst && xbt_swag_belongs(&elem, &(elem.constraint->enabled_element_set)))
272 current_share += elem.get_concurrency();
276 // Check if we need to disable the variable
277 if (var->sharing_weight > 0 && var->concurrency_share - current_share > cnst->get_concurrency_slack()) {
278 double weight = var->sharing_weight;
280 for (s_lmm_element_t const& elem : var->cnsts)
281 on_disabled_var(elem.constraint);
282 consumption_weight = 0;
283 var->staged_weight = weight;
284 xbt_assert(not var->sharing_weight);
287 xbt_assert(var->cnsts.size() < var->cnsts.capacity(), "Too much constraints");
289 var->cnsts.resize(var->cnsts.size() + 1);
290 s_lmm_element_t& elem = var->cnsts.back();
292 elem.consumption_weight = consumption_weight;
293 elem.constraint = cnst;
296 if (var->sharing_weight) {
297 xbt_swag_insert_at_head(&elem, &(elem.constraint->enabled_element_set));
298 elem.increase_concurrency();
300 xbt_swag_insert_at_tail(&elem, &(elem.constraint->disabled_element_set));
302 if (not selective_update_active) {
303 make_constraint_active(cnst);
304 } else if (elem.consumption_weight > 0 || var->sharing_weight > 0) {
305 make_constraint_active(cnst);
306 update_modified_set(cnst);
307 // TODOLATER: Why do we need this second call?
308 if (var->cnsts.size() > 1)
309 update_modified_set(var->cnsts[0].constraint);
315 void s_lmm_system_t::expand_add(lmm_constraint_t cnst, lmm_variable_t var, double value)
321 // BEWARE: In case you have multiple elements in one constraint, this will always add value to the first element.
322 auto elem_it = std::find_if(begin(var->cnsts), end(var->cnsts),
323 [&cnst](s_lmm_element_t const& x) { return x.constraint == cnst; });
324 if (elem_it != end(var->cnsts)) {
325 s_lmm_element_t& elem = *elem_it;
326 if (var->sharing_weight)
327 elem.decrease_concurrency();
329 if (cnst->sharing_policy)
330 elem.consumption_weight += value;
332 elem.consumption_weight = std::max(elem.consumption_weight, value);
334 // We need to check that increasing value of the element does not cross the concurrency limit
335 if (var->sharing_weight) {
336 if (cnst->get_concurrency_slack() < elem.get_concurrency()) {
337 double weight = var->sharing_weight;
339 for (s_lmm_element_t const& elem2 : var->cnsts)
340 on_disabled_var(elem2.constraint);
341 var->staged_weight = weight;
342 xbt_assert(not var->sharing_weight);
344 elem.increase_concurrency();
346 update_modified_set(cnst);
348 expand(cnst, var, value);
353 lmm_variable_t s_lmm_constraint_t::get_variable(lmm_element_t* elem) const
355 if (*elem == nullptr) {
356 // That is the first call, pick the first element among enabled_element_set (or disabled_element_set if
357 // enabled_element_set is empty)
358 *elem = (lmm_element_t)xbt_swag_getFirst(&enabled_element_set);
359 if (*elem == nullptr)
360 *elem = (lmm_element_t)xbt_swag_getFirst(&disabled_element_set);
362 // elem is not null, so we carry on
363 if (xbt_swag_belongs(*elem, &enabled_element_set)) {
364 // Look at enabled_element_set, and jump to disabled_element_set when finished
365 *elem = (lmm_element_t)xbt_swag_getNext(*elem, enabled_element_set.offset);
366 if (*elem == nullptr)
367 *elem = (lmm_element_t)xbt_swag_getFirst(&disabled_element_set);
369 *elem = (lmm_element_t)xbt_swag_getNext(*elem, disabled_element_set.offset);
373 return (*elem)->variable;
378 // if we modify the swag between calls, normal version may loop forever
379 // this safe version ensures that we browse the swag elements only once
380 lmm_variable_t s_lmm_constraint_t::get_variable_safe(lmm_element_t* elem, lmm_element_t* nextelem, int* numelem) const
382 if (*elem == nullptr) {
383 *elem = (lmm_element_t)xbt_swag_getFirst(&enabled_element_set);
384 *numelem = xbt_swag_size(&enabled_element_set) + xbt_swag_size(&disabled_element_set) - 1;
385 if (*elem == nullptr)
386 *elem = (lmm_element_t)xbt_swag_getFirst(&disabled_element_set);
395 // elem is not null, so we carry on
396 if (xbt_swag_belongs(*elem, &enabled_element_set)) {
397 // Look at enabled_element_set, and jump to disabled_element_set when finished
398 *nextelem = (lmm_element_t)xbt_swag_getNext(*elem, enabled_element_set.offset);
399 if (*nextelem == nullptr)
400 *nextelem = (lmm_element_t)xbt_swag_getFirst(&disabled_element_set);
402 *nextelem = (lmm_element_t)xbt_swag_getNext(*elem, disabled_element_set.offset);
404 return (*elem)->variable;
409 static inline void saturated_constraints_update(double usage, int cnst_light_num, dyn_light_t& saturated_constraints,
412 xbt_assert(usage > 0, "Impossible");
414 if (*min_usage < 0 || *min_usage > usage) {
416 XBT_HERE(" min_usage=%f (cnst->remaining / cnst->usage =%f)", *min_usage, usage);
417 saturated_constraints.assign(1, cnst_light_num);
418 } else if (*min_usage == usage) {
419 saturated_constraints.emplace_back(cnst_light_num);
423 static inline void saturated_variable_set_update(s_lmm_constraint_light_t* cnst_light_tab,
424 const dyn_light_t& saturated_constraints, lmm_system_t sys)
426 /* Add active variables (i.e. variables that need to be set) from the set of constraints to saturate
428 for (int const& saturated_cnst : saturated_constraints) {
429 lmm_constraint_light_t cnst = &cnst_light_tab[saturated_cnst];
431 xbt_swag_t elem_list = &(cnst->cnst->active_element_set);
432 xbt_swag_foreach(_elem, elem_list)
434 lmm_element_t elem = (lmm_element_t)_elem;
435 // Visiting active_element_set, so, by construction, should never get a zero weight, correct?
436 xbt_assert(elem->variable->sharing_weight > 0);
437 if (elem->consumption_weight > 0)
438 xbt_swag_insert(elem->variable, &(sys->saturated_variable_set));
443 void s_lmm_system_t::print()
445 std::string buf = std::string("MAX-MIN ( ");
448 /* Printing Objective */
449 xbt_swag_t var_list = &variable_set;
450 xbt_swag_foreach(_var, var_list)
452 lmm_variable_t var = (lmm_variable_t)_var;
453 buf = buf + "'" + std::to_string(var->id_int) + "'(" + std::to_string(var->sharing_weight) + ") ";
456 XBT_DEBUG("%20s", buf.c_str());
459 XBT_DEBUG("Constraints");
460 /* Printing Constraints */
462 xbt_swag_t cnst_list = &active_constraint_set;
463 xbt_swag_foreach(_cnst, cnst_list)
465 lmm_constraint_t cnst = (lmm_constraint_t)_cnst;
467 // Show the enabled variables
469 xbt_swag_t elem_list = &(cnst->enabled_element_set);
471 buf += ((cnst->sharing_policy) ? "(" : "max(");
472 xbt_swag_foreach(_elem, elem_list)
474 lmm_element_t elem = (lmm_element_t)_elem;
475 buf = buf + std::to_string(elem->consumption_weight) + ".'" + std::to_string(elem->variable->id_int) + "'(" +
476 std::to_string(elem->variable->value) + ")" + ((cnst->sharing_policy) ? " + " : " , ");
477 if (cnst->sharing_policy)
478 sum += elem->consumption_weight * elem->variable->value;
480 sum = std::max(sum, elem->consumption_weight * elem->variable->value);
482 // TODO: Adding disabled elements only for test compatibility, but do we really want them to be printed?
483 elem_list = &(cnst->disabled_element_set);
484 xbt_swag_foreach(_elem, elem_list)
486 lmm_element_t elem = (lmm_element_t)_elem;
487 buf = buf + std::to_string(elem->consumption_weight) + ".'" + std::to_string(elem->variable->id_int) + "'(" +
488 std::to_string(elem->variable->value) + ")" + ((cnst->sharing_policy) ? " + " : " , ");
489 if (cnst->sharing_policy)
490 sum += elem->consumption_weight * elem->variable->value;
492 sum = std::max(sum, elem->consumption_weight * elem->variable->value);
495 buf = buf + "0) <= " + std::to_string(cnst->bound) + " ('" + std::to_string(cnst->id_int) + "')";
497 if (not cnst->sharing_policy) {
498 buf += " [MAX-Constraint]";
500 XBT_DEBUG("%s", buf.c_str());
502 xbt_assert(not double_positive(sum - cnst->bound, cnst->bound * sg_maxmin_precision),
503 "Incorrect value (%f is not smaller than %f): %g", sum, cnst->bound, sum - cnst->bound);
506 XBT_DEBUG("Variables");
507 /* Printing Result */
508 xbt_swag_foreach(_var, var_list)
510 lmm_variable_t var = (lmm_variable_t)_var;
511 if (var->bound > 0) {
512 XBT_DEBUG("'%d'(%f) : %f (<=%f)", var->id_int, var->sharing_weight, var->value, var->bound);
513 xbt_assert(not double_positive(var->value - var->bound, var->bound * sg_maxmin_precision),
514 "Incorrect value (%f is not smaller than %f", var->value, var->bound);
516 XBT_DEBUG("'%d'(%f) : %f", var->id_int, var->sharing_weight, var->value);
521 void s_lmm_system_t::solve()
526 double min_usage = -1;
527 double min_bound = -1;
532 XBT_IN("(sys=%p)", this);
534 /* Compute Usage and store the variables that reach the maximum. If selective_update_active is true, only constraints
535 * that changed are considered. Otherwise all constraints with active actions are considered.
537 xbt_swag_t cnst_list = selective_update_active ? &modified_constraint_set : &active_constraint_set;
539 XBT_DEBUG("Active constraints : %d", xbt_swag_size(cnst_list));
540 /* Init: Only modified code portions: reset the value of active variables */
541 xbt_swag_foreach(_cnst, cnst_list)
543 lmm_constraint_t cnst = (lmm_constraint_t)_cnst;
544 xbt_swag_t elem_list = &(cnst->enabled_element_set);
545 xbt_swag_foreach(_elem, elem_list)
547 lmm_variable_t var = ((lmm_element_t)_elem)->variable;
548 xbt_assert(var->sharing_weight > 0.0);
553 s_lmm_constraint_light_t* cnst_light_tab = new s_lmm_constraint_light_t[xbt_swag_size(cnst_list)]();
554 int cnst_light_num = 0;
555 dyn_light_t saturated_constraints;
557 xbt_swag_foreach_safe(_cnst, _cnst_next, cnst_list)
559 lmm_constraint_t cnst = (lmm_constraint_t)_cnst;
560 /* INIT: Collect constraints that actually need to be saturated (i.e remaining and usage are strictly positive)
561 * into cnst_light_tab. */
562 cnst->remaining = cnst->bound;
563 if (not double_positive(cnst->remaining, cnst->bound * sg_maxmin_precision))
566 xbt_swag_t elem_list = &(cnst->enabled_element_set);
567 xbt_swag_foreach(_elem, elem_list)
569 lmm_element_t elem = (lmm_element_t)_elem;
570 xbt_assert(elem->variable->sharing_weight > 0);
571 if (elem->consumption_weight > 0) {
572 if (cnst->sharing_policy)
573 cnst->usage += elem->consumption_weight / elem->variable->sharing_weight;
574 else if (cnst->usage < elem->consumption_weight / elem->variable->sharing_weight)
575 cnst->usage = elem->consumption_weight / elem->variable->sharing_weight;
578 simgrid::surf::Action* action = static_cast<simgrid::surf::Action*>(elem->variable->id);
579 if (keep_track && not action->is_linked())
580 keep_track->push_back(*action);
583 XBT_DEBUG("Constraint '%d' usage: %f remaining: %f concurrency: %i<=%i<=%i", cnst->id_int, cnst->usage,
584 cnst->remaining, cnst->concurrency_current, cnst->concurrency_maximum, cnst->get_concurrency_limit());
585 /* Saturated constraints update */
587 if (cnst->usage > 0) {
588 cnst_light_tab[cnst_light_num].cnst = cnst;
589 cnst->cnst_light = &(cnst_light_tab[cnst_light_num]);
590 cnst_light_tab[cnst_light_num].remaining_over_usage = cnst->remaining / cnst->usage;
591 saturated_constraints_update(cnst_light_tab[cnst_light_num].remaining_over_usage, cnst_light_num,
592 saturated_constraints, &min_usage);
593 xbt_assert(cnst->active_element_set.count > 0,
594 "There is no sense adding a constraint that has no active element!");
599 saturated_variable_set_update(cnst_light_tab, saturated_constraints, this);
601 /* Saturated variables update */
603 /* Fix the variables that have to be */
604 xbt_swag_t var_list = &saturated_variable_set;
606 lmm_variable_t var = nullptr;
607 xbt_swag_foreach(_var, var_list)
609 var = (lmm_variable_t)_var;
610 if (var->sharing_weight <= 0.0)
612 /* First check if some of these variables could reach their upper bound and update min_bound accordingly. */
613 XBT_DEBUG("var=%d, var->bound=%f, var->weight=%f, min_usage=%f, var->bound*var->weight=%f", var->id_int,
614 var->bound, var->sharing_weight, min_usage, var->bound * var->sharing_weight);
615 if ((var->bound > 0) && (var->bound * var->sharing_weight < min_usage)) {
617 min_bound = var->bound * var->sharing_weight;
619 min_bound = std::min(min_bound, (var->bound * var->sharing_weight));
620 XBT_DEBUG("Updated min_bound=%f", min_bound);
624 while ((var = (lmm_variable_t)xbt_swag_getFirst(var_list))) {
626 // If no variable could reach its bound, deal iteratively the constraints usage ( at worst one constraint is
627 // saturated at each cycle)
628 var->value = min_usage / var->sharing_weight;
629 XBT_DEBUG("Setting var (%d) value to %f\n", var->id_int, var->value);
631 // If there exist a variable that can reach its bound, only update it (and other with the same bound) for now.
632 if (double_equals(min_bound, var->bound * var->sharing_weight, sg_maxmin_precision)) {
633 var->value = var->bound;
634 XBT_DEBUG("Setting %p (%d) value to %f\n", var, var->id_int, var->value);
636 // Variables which bound is different are not considered for this cycle, but they will be afterwards.
637 XBT_DEBUG("Do not consider %p (%d) \n", var, var->id_int);
638 xbt_swag_remove(var, var_list);
642 XBT_DEBUG("Min usage: %f, Var(%d)->weight: %f, Var(%d)->value: %f ", min_usage, var->id_int, var->sharing_weight,
643 var->id_int, var->value);
645 /* Update the usage of contraints where this variable is involved */
646 for (s_lmm_element_t& elem : var->cnsts) {
647 lmm_constraint_t cnst = elem.constraint;
648 if (cnst->sharing_policy) {
649 // Remember: shared constraints require that sum(elem.value * var->value) < cnst->bound
650 double_update(&(cnst->remaining), elem.consumption_weight * var->value, cnst->bound * sg_maxmin_precision);
651 double_update(&(cnst->usage), elem.consumption_weight / var->sharing_weight, sg_maxmin_precision);
652 // If the constraint is saturated, remove it from the set of active constraints (light_tab)
653 if (not double_positive(cnst->usage, sg_maxmin_precision) ||
654 not double_positive(cnst->remaining, cnst->bound * sg_maxmin_precision)) {
655 if (cnst->cnst_light) {
656 int index = (cnst->cnst_light - cnst_light_tab);
657 XBT_DEBUG("index: %d \t cnst_light_num: %d \t || usage: %f remaining: %f bound: %f ", index,
658 cnst_light_num, cnst->usage, cnst->remaining, cnst->bound);
659 cnst_light_tab[index] = cnst_light_tab[cnst_light_num - 1];
660 cnst_light_tab[index].cnst->cnst_light = &cnst_light_tab[index];
662 cnst->cnst_light = nullptr;
665 cnst->cnst_light->remaining_over_usage = cnst->remaining / cnst->usage;
667 elem.make_inactive();
669 // Remember: non-shared constraints only require that max(elem.value * var->value) < cnst->bound
671 elem.make_inactive();
672 xbt_swag_t elem_list = &(cnst->enabled_element_set);
673 xbt_swag_foreach(_elem, elem_list)
675 lmm_element_t elem2 = static_cast<lmm_element_t>(_elem);
676 xbt_assert(elem2->variable->sharing_weight > 0);
677 if (elem2->variable->value > 0)
679 if (elem2->consumption_weight > 0)
680 cnst->usage = std::max(cnst->usage, elem2->consumption_weight / elem2->variable->sharing_weight);
682 // If the constraint is saturated, remove it from the set of active constraints (light_tab)
683 if (not double_positive(cnst->usage, sg_maxmin_precision) ||
684 not double_positive(cnst->remaining, cnst->bound * sg_maxmin_precision)) {
685 if (cnst->cnst_light) {
686 int index = (cnst->cnst_light - cnst_light_tab);
687 XBT_DEBUG("index: %d \t cnst_light_num: %d \t || \t cnst: %p \t cnst->cnst_light: %p "
688 "\t cnst_light_tab: %p usage: %f remaining: %f bound: %f ",
689 index, cnst_light_num, cnst, cnst->cnst_light, cnst_light_tab, cnst->usage, cnst->remaining,
691 cnst_light_tab[index] = cnst_light_tab[cnst_light_num - 1];
692 cnst_light_tab[index].cnst->cnst_light = &cnst_light_tab[index];
694 cnst->cnst_light = nullptr;
697 cnst->cnst_light->remaining_over_usage = cnst->remaining / cnst->usage;
698 xbt_assert(cnst->active_element_set.count > 0,
699 "Should not keep a maximum constraint that has no active"
700 " element! You want to check the maxmin precision and possible rounding effects.");
704 xbt_swag_remove(var, var_list);
707 /* Find out which variables reach the maximum */
710 saturated_constraints.clear();
712 for (pos = 0; pos < cnst_light_num; pos++) {
713 xbt_assert(cnst_light_tab[pos].cnst->active_element_set.count > 0,
714 "Cannot saturate more a constraint that has"
715 " no active element! You may want to change the maxmin precision (--cfg=maxmin/precision:<new_value>)"
716 " because of possible rounding effects.\n\tFor the record, the usage of this constraint is %g while "
717 "the maxmin precision to which it is compared is %g.\n\tThe usage of the previous constraint is %g.",
718 cnst_light_tab[pos].cnst->usage, sg_maxmin_precision, cnst_light_tab[pos - 1].cnst->usage);
719 saturated_constraints_update(cnst_light_tab[pos].remaining_over_usage, pos, saturated_constraints, &min_usage);
722 saturated_variable_set_update(cnst_light_tab, saturated_constraints, this);
724 } while (cnst_light_num > 0);
727 if (selective_update_active)
728 remove_all_modified_set();
730 if (XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug)) {
736 delete[] cnst_light_tab;
740 void lmm_solve(lmm_system_t sys)
745 /** \brief Attribute the value bound to var->bound.
747 * \param sys the lmm_system_t
748 * \param var the lmm_variable_t
749 * \param bound the new bound to associate with var
751 * Makes var->bound equal to bound. Whenever this function is called a change is signed in the system. To
752 * avoid false system changing detection it is a good idea to test (bound != 0) before calling it.
754 void s_lmm_system_t::update_variable_bound(lmm_variable_t var, double bound)
759 if (not var->cnsts.empty())
760 update_modified_set(var->cnsts[0].constraint);
763 void s_lmm_variable_t::initialize(simgrid::surf::Action* id_value, double sharing_weight_value, double bound_value,
764 int number_of_constraints, unsigned visited_value)
767 id_int = Global_debug_id++;
768 cnsts.reserve(number_of_constraints);
769 sharing_weight = sharing_weight_value;
772 concurrency_share = 1;
774 visited = visited_value;
778 func_fp = func_fp_def;
779 func_fpi = func_fpi_def;
781 variable_set_hookup.next = nullptr;
782 variable_set_hookup.prev = nullptr;
783 saturated_variable_set_hookup.next = nullptr;
784 saturated_variable_set_hookup.prev = nullptr;
787 int s_lmm_variable_t::get_min_concurrency_slack() const
789 int minslack = std::numeric_limits<int>::max();
790 for (s_lmm_element_t const& elem : cnsts) {
791 int slack = elem.constraint->get_concurrency_slack();
792 if (slack < minslack) {
793 // This is only an optimization, to avoid looking at more constraints when slack is already zero
802 // Small remark: In this implementation of lmm_enable_var and lmm_disable_var, we will meet multiple times with var when
803 // running sys->update_modified_set.
804 // A priori not a big performance issue, but we might do better by calling sys->update_modified_set within the for loops
805 // (after doing the first for enabling==1, and before doing the last for disabling==1)
806 void s_lmm_system_t::enable_var(lmm_variable_t var)
808 xbt_assert(not XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug) || var->can_enable());
810 var->sharing_weight = var->staged_weight;
811 var->staged_weight = 0;
813 // Enabling the variable, move to var to list head. Subtlety is: here, we need to call update_modified_set AFTER
814 // moving at least one element of var.
816 xbt_swag_remove(var, &variable_set);
817 xbt_swag_insert_at_head(var, &variable_set);
818 for (s_lmm_element_t& elem : var->cnsts) {
819 xbt_swag_remove(&elem, &(elem.constraint->disabled_element_set));
820 xbt_swag_insert_at_head(&elem, &(elem.constraint->enabled_element_set));
821 elem.increase_concurrency();
823 if (not var->cnsts.empty())
824 update_modified_set(var->cnsts[0].constraint);
826 // When used within on_disabled_var, we would get an assertion fail, because transiently there can be variables
827 // that are staged and could be activated.
828 // Anyway, caller functions all call check_concurrency() in the end.
831 void s_lmm_system_t::disable_var(lmm_variable_t var)
833 xbt_assert(not var->staged_weight, "Staged weight should have been cleared");
834 // Disabling the variable, move to var to list tail. Subtlety is: here, we need to call update_modified_set
835 // BEFORE moving the last element of var.
836 xbt_swag_remove(var, &variable_set);
837 xbt_swag_insert_at_tail(var, &variable_set);
838 if (not var->cnsts.empty())
839 update_modified_set(var->cnsts[0].constraint);
840 for (s_lmm_element_t& elem : var->cnsts) {
841 xbt_swag_remove(&elem, &(elem.constraint->enabled_element_set));
842 xbt_swag_insert_at_tail(&elem, &(elem.constraint->disabled_element_set));
844 xbt_swag_remove(&elem, &(elem.constraint->active_element_set));
846 elem.decrease_concurrency();
849 var->sharing_weight = 0.0;
850 var->staged_weight = 0.0;
855 /* /brief Find variables that can be enabled and enable them.
857 * Assuming that the variable has already been removed from non-zero weights
858 * Can we find a staged variable to add?
859 * If yes, check that none of the constraints that this variable is involved in is at the limit of its concurrency
860 * And then add it to enabled variables
862 void s_lmm_system_t::on_disabled_var(lmm_constraint_t cnstr)
864 if (cnstr->get_concurrency_limit() < 0)
867 int numelem = xbt_swag_size(&(cnstr->disabled_element_set));
871 lmm_element_t elem = (lmm_element_t)xbt_swag_getFirst(&(cnstr->disabled_element_set));
873 // Cannot use xbt_swag_foreach, because lmm_enable_var will modify disabled_element_set.. within the loop
874 while (numelem-- && elem) {
876 lmm_element_t nextelem = (lmm_element_t)xbt_swag_getNext(elem, cnstr->disabled_element_set.offset);
878 if (elem->variable->staged_weight > 0 && elem->variable->can_enable()) {
879 // Found a staged variable
880 // TODOLATER: Add random timing function to model reservation protocol fuzziness? Then how to make sure that
881 // staged variables will eventually be called?
882 enable_var(elem->variable);
885 xbt_assert(cnstr->concurrency_current <= cnstr->get_concurrency_limit(), "Concurrency overflow!");
886 if (cnstr->concurrency_current == cnstr->get_concurrency_limit())
892 // We could get an assertion fail, because transiently there can be variables that are staged and could be activated.
893 // And we need to go through all constraints of the disabled var before getting back a coherent state.
894 // Anyway, caller functions all call check_concurrency() in the end.
897 /* \brief update the weight of a variable, and enable/disable it.
898 * @return Returns whether a change was made
900 void s_lmm_system_t::update_variable_weight(lmm_variable_t var, double weight)
902 xbt_assert(weight >= 0, "Variable weight should not be negative!");
904 if (weight == var->sharing_weight)
907 int enabling_var = (weight > 0 && var->sharing_weight <= 0);
908 int disabling_var = (weight <= 0 && var->sharing_weight > 0);
910 XBT_IN("(sys=%p, var=%p, weight=%f)", this, var, weight);
914 // Are we enabling this variable?
916 var->staged_weight = weight;
917 int minslack = var->get_min_concurrency_slack();
918 if (minslack < var->concurrency_share) {
919 XBT_DEBUG("Staging var (instead of enabling) because min concurrency slack %i, with weight %f and concurrency"
921 minslack, weight, var->concurrency_share);
924 XBT_DEBUG("Enabling var with min concurrency slack %i", minslack);
926 } else if (disabling_var) {
927 // Are we disabling this variable?
930 var->sharing_weight = weight;
938 void s_lmm_system_t::update_constraint_bound(lmm_constraint_t cnst, double bound)
941 update_modified_set(cnst);
945 /** \brief Update the constraint set propagating recursively to other constraints so the system should not be entirely
948 * \param sys the lmm_system_t
949 * \param cnst the lmm_constraint_t affected by the change
951 * A recursive algorithm to optimize the system recalculation selecting only constraints that have changed. Each
952 * constraint change is propagated to the list of constraints for each variable.
954 void s_lmm_system_t::update_modified_set_rec(lmm_constraint_t cnst)
958 xbt_swag_foreach(_elem, &cnst->enabled_element_set)
960 lmm_variable_t var = ((lmm_element_t)_elem)->variable;
961 for (s_lmm_element_t const& elem : var->cnsts) {
962 if (var->visited == visited_counter)
964 if (elem.constraint != cnst && not xbt_swag_belongs(elem.constraint, &modified_constraint_set)) {
965 xbt_swag_insert(elem.constraint, &modified_constraint_set);
966 update_modified_set_rec(elem.constraint);
969 // var will be ignored in later visits as long as sys->visited_counter does not move
970 var->visited = visited_counter;
974 void s_lmm_system_t::update_modified_set(lmm_constraint_t cnst)
976 /* nothing to do if selective update isn't active */
977 if (selective_update_active && not xbt_swag_belongs(cnst, &modified_constraint_set)) {
978 xbt_swag_insert(cnst, &modified_constraint_set);
979 update_modified_set_rec(cnst);
983 void s_lmm_system_t::remove_all_modified_set()
985 // We cleverly un-flag all variables just by incrementing visited_counter
986 // In effect, the var->visited value will no more be equal to visited counter
987 // To be clean, when visited counter has wrapped around, we force these var->visited values so that variables that
988 // were in the modified a long long time ago are not wrongly skipped here, which would lead to very nasty bugs
989 // (i.e. not readibily reproducible, and requiring a lot of run time before happening).
990 if (++visited_counter == 1) {
991 /* the counter wrapped around, reset each variable->visited */
993 xbt_swag_foreach(_var, &variable_set)((lmm_variable_t)_var)->visited = 0;
995 xbt_swag_reset(&modified_constraint_set);
999 * Returns resource load (in flop per second, or byte per second, or similar)
1001 * If the resource is shared (the default case), the load is sum of resource usage made by every variables located on
1004 * If the resource is not shared (ie in FATPIPE mode), then the load is the max (not the sum) of all resource usages
1005 * located on this resource.
1007 * \param cnst the lmm_constraint_t associated to the resource
1009 double s_lmm_constraint_t::get_usage() const
1011 double result = 0.0;
1012 const_xbt_swag_t elem_list = &enabled_element_set;
1015 xbt_swag_foreach(_elem, elem_list)
1017 lmm_element_t elem = (lmm_element_t)_elem;
1018 if (elem->consumption_weight > 0) {
1020 result += elem->consumption_weight * elem->variable->value;
1021 else if (result < elem->consumption_weight * elem->variable->value)
1022 result = std::max(result, elem->consumption_weight * elem->variable->value);
1028 int s_lmm_constraint_t::get_variable_amount() const
1031 const_xbt_swag_t elem_list = &enabled_element_set;
1034 xbt_swag_foreach(_elem, elem_list)
1036 lmm_element_t elem = (lmm_element_t)_elem;
1037 if (elem->consumption_weight > 0)