1 /* Copyright (c) 2004-2019. 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 #include "src/kernel/lmm/maxmin.hpp"
7 #include "src/surf/surf_interface.hpp"
8 #include "xbt/backtrace.hpp"
10 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(surf_maxmin, surf, "Logging specific to SURF (maxmin)");
12 double sg_maxmin_precision = 0.00001; /* Change this with --cfg=maxmin/precision:VALUE */
13 double sg_surf_precision = 0.00001; /* Change this with --cfg=surf/precision:VALUE */
14 int sg_concurrency_limit = -1; /* Change this with --cfg=maxmin/concurrency-limit:VALUE */
20 typedef std::vector<int> dyn_light_t;
22 int Variable::next_rank_ = 1;
23 int Constraint::next_rank_ = 1;
25 System* make_new_maxmin_system(bool selective_update)
27 return new System(selective_update);
30 int Element::get_concurrency() const
32 // Ignore element with weight less than one (e.g. cross-traffic)
33 return (consumption_weight >= 1) ? 1 : 0;
34 // There are other alternatives, but they will change the behaviour of the model..
35 // So do not use it unless you want to make a new model.
36 // If you do, remember to change the variables concurrency share to reflect it.
37 // Potential examples are:
38 // return (elem->weight>0)?1:0;//Include element as soon as weight is non-zero
39 // return (int)ceil(elem->weight);//Include element as the rounded-up integer value of the element weight
42 void Element::decrease_concurrency()
44 xbt_assert(constraint->concurrency_current_ >= get_concurrency());
45 constraint->concurrency_current_ -= get_concurrency();
48 void Element::increase_concurrency()
50 constraint->concurrency_current_ += get_concurrency();
52 if (constraint->concurrency_current_ > constraint->concurrency_maximum_)
53 constraint->concurrency_maximum_ = constraint->concurrency_current_;
55 xbt_assert(constraint->get_concurrency_limit() < 0 ||
56 constraint->concurrency_current_ <= constraint->get_concurrency_limit(),
57 "Concurrency limit overflow!");
60 void System::check_concurrency() const
62 // These checks are very expensive, so do them only if we want to debug SURF LMM
63 if (not XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug))
66 for (Constraint const& cnst : constraint_set) {
68 for (Element const& elem : cnst.enabled_element_set_) {
69 xbt_assert(elem.variable->sharing_penalty_ > 0);
70 concurrency += elem.get_concurrency();
73 for (Element const& elem : cnst.disabled_element_set_) {
74 // We should have staged variables only if concurrency is reached in some constraint
75 xbt_assert(cnst.get_concurrency_limit() < 0 || elem.variable->staged_penalty_ == 0 ||
76 elem.variable->get_min_concurrency_slack() < elem.variable->concurrency_share_,
77 "should not have staged variable!");
80 xbt_assert(cnst.get_concurrency_limit() < 0 || cnst.get_concurrency_limit() >= concurrency,
81 "concurrency check failed!");
82 xbt_assert(cnst.concurrency_current_ == concurrency, "concurrency_current is out-of-date!");
85 // Check that for each variable, all corresponding elements are in the same state (i.e. same element sets)
86 for (Variable const& var : variable_set) {
87 if (var.cnsts_.empty())
90 const Element& elem = var.cnsts_[0];
91 int belong_to_enabled = elem.enabled_element_set_hook.is_linked();
92 int belong_to_disabled = elem.disabled_element_set_hook.is_linked();
93 int belong_to_active = elem.active_element_set_hook.is_linked();
95 for (Element const& elem2 : var.cnsts_) {
96 xbt_assert(belong_to_enabled == elem2.enabled_element_set_hook.is_linked(),
97 "Variable inconsistency (1): enabled_element_set");
98 xbt_assert(belong_to_disabled == elem2.disabled_element_set_hook.is_linked(),
99 "Variable inconsistency (2): disabled_element_set");
100 xbt_assert(belong_to_active == elem2.active_element_set_hook.is_linked(),
101 "Variable inconsistency (3): active_element_set");
106 void System::var_free(Variable* var)
108 XBT_IN("(sys=%p, var=%p)", this, var);
111 // TODOLATER Can do better than that by leaving only the variable in only one enabled_element_set, call
112 // update_modified_set, and then remove it..
113 if (not var->cnsts_.empty())
114 update_modified_set(var->cnsts_[0].constraint);
116 for (Element& elem : var->cnsts_) {
117 if (var->sharing_penalty_ > 0)
118 elem.decrease_concurrency();
119 if (elem.enabled_element_set_hook.is_linked())
120 simgrid::xbt::intrusive_erase(elem.constraint->enabled_element_set_, elem);
121 if (elem.disabled_element_set_hook.is_linked())
122 simgrid::xbt::intrusive_erase(elem.constraint->disabled_element_set_, elem);
123 if (elem.active_element_set_hook.is_linked())
124 simgrid::xbt::intrusive_erase(elem.constraint->active_element_set_, elem);
125 int nelements = elem.constraint->enabled_element_set_.size() + elem.constraint->disabled_element_set_.size();
127 make_constraint_inactive(elem.constraint);
129 on_disabled_var(elem.constraint);
136 xbt_mallocator_release(variable_mallocator_, var);
140 System::System(bool selective_update) : selective_update_active(selective_update)
142 XBT_DEBUG("Setting selective_update_active flag to %d", selective_update_active);
144 if (selective_update)
145 modified_set_ = new kernel::resource::Action::ModifiedSet();
153 while ((var = extract_variable())) {
154 auto demangled = simgrid::xbt::demangle(var->id_ ? typeid(*var->id_).name() : "(unidentified)");
155 XBT_WARN("Probable bug: a %s variable (#%d) not removed before the LMM system destruction.", demangled.get(),
159 while ((cnst = extract_constraint()))
162 xbt_mallocator_free(variable_mallocator_);
163 delete modified_set_;
166 void System::cnst_free(Constraint* cnst)
168 make_constraint_inactive(cnst);
172 Constraint::Constraint(resource::Resource* id_value, double bound_value) : bound_(bound_value), id_(id_value)
174 rank_ = next_rank_++;
178 concurrency_limit_ = sg_concurrency_limit;
179 concurrency_current_ = 0;
180 concurrency_maximum_ = 0;
181 sharing_policy_ = s4u::Link::SharingPolicy::SHARED;
185 cnst_light_ = nullptr;
188 Constraint* System::constraint_new(resource::Resource* id, double bound_value)
190 Constraint* cnst = new Constraint(id, bound_value);
191 insert_constraint(cnst);
195 void* System::variable_mallocator_new_f()
200 void System::variable_mallocator_free_f(void* var)
202 delete static_cast<Variable*>(var);
205 Variable* System::variable_new(resource::Action* id, double sharing_penalty, double bound, size_t number_of_constraints)
207 XBT_IN("(sys=%p, id=%p, penalty=%f, bound=%f, num_cons =%zu)", this, id, sharing_penalty, bound,
208 number_of_constraints);
210 Variable* var = static_cast<Variable*>(xbt_mallocator_get(variable_mallocator_));
211 var->initialize(id, sharing_penalty, bound, number_of_constraints, visited_counter_ - 1);
212 if (sharing_penalty > 0)
213 variable_set.push_front(*var);
215 variable_set.push_back(*var);
217 XBT_OUT(" returns %p", var);
221 void System::variable_free(Variable* var)
223 remove_variable(var);
227 void System::variable_free_all()
230 while ((var = extract_variable()))
234 void System::expand(Constraint* cnst, Variable* var, double consumption_weight)
238 // Check if this variable already has an active element in this constraint
239 // If it does, substract it from the required slack
240 int current_share = 0;
241 if (var->concurrency_share_ > 1) {
242 for (Element& elem : var->cnsts_) {
243 if (elem.constraint == cnst && elem.enabled_element_set_hook.is_linked())
244 current_share += elem.get_concurrency();
248 // Check if we need to disable the variable
249 if (var->sharing_penalty_ > 0 && var->concurrency_share_ - current_share > cnst->get_concurrency_slack()) {
250 double penalty = var->sharing_penalty_;
252 for (Element const& elem : var->cnsts_)
253 on_disabled_var(elem.constraint);
254 consumption_weight = 0;
255 var->staged_penalty_ = penalty;
256 xbt_assert(not var->sharing_penalty_);
259 xbt_assert(var->cnsts_.size() < var->cnsts_.capacity(), "Too much constraints");
261 var->cnsts_.resize(var->cnsts_.size() + 1);
262 Element& elem = var->cnsts_.back();
264 elem.consumption_weight = consumption_weight;
265 elem.constraint = cnst;
268 if (var->sharing_penalty_) {
269 elem.constraint->enabled_element_set_.push_front(elem);
270 elem.increase_concurrency();
272 elem.constraint->disabled_element_set_.push_back(elem);
274 if (not selective_update_active) {
275 make_constraint_active(cnst);
276 } else if (elem.consumption_weight > 0 || var->sharing_penalty_ > 0) {
277 make_constraint_active(cnst);
278 update_modified_set(cnst);
279 // TODOLATER: Why do we need this second call?
280 if (var->cnsts_.size() > 1)
281 update_modified_set(var->cnsts_[0].constraint);
287 void System::expand_add(Constraint* cnst, Variable* var, double value)
293 // BEWARE: In case you have multiple elements in one constraint, this will always add value to the first element.
295 std::find_if(begin(var->cnsts_), end(var->cnsts_), [&cnst](Element const& x) { return x.constraint == cnst; });
296 if (elem_it != end(var->cnsts_)) {
297 Element& elem = *elem_it;
298 if (var->sharing_penalty_)
299 elem.decrease_concurrency();
301 if (cnst->sharing_policy_ != s4u::Link::SharingPolicy::FATPIPE)
302 elem.consumption_weight += value;
304 elem.consumption_weight = std::max(elem.consumption_weight, value);
306 // We need to check that increasing value of the element does not cross the concurrency limit
307 if (var->sharing_penalty_) {
308 if (cnst->get_concurrency_slack() < elem.get_concurrency()) {
309 double penalty = var->sharing_penalty_;
311 for (Element const& elem2 : var->cnsts_)
312 on_disabled_var(elem2.constraint);
313 var->staged_penalty_ = penalty;
314 xbt_assert(not var->sharing_penalty_);
316 elem.increase_concurrency();
318 update_modified_set(cnst);
320 expand(cnst, var, value);
325 Variable* Constraint::get_variable(const Element** elem) const
327 if (*elem == nullptr) {
328 // That is the first call, pick the first element among enabled_element_set (or disabled_element_set if
329 // enabled_element_set is empty)
330 if (not enabled_element_set_.empty())
331 *elem = &enabled_element_set_.front();
332 else if (not disabled_element_set_.empty())
333 *elem = &disabled_element_set_.front();
337 // elem is not null, so we carry on
338 if ((*elem)->enabled_element_set_hook.is_linked()) {
339 // Look at enabled_element_set, and jump to disabled_element_set when finished
340 auto iter = std::next(enabled_element_set_.iterator_to(**elem));
341 if (iter != std::end(enabled_element_set_))
343 else if (not disabled_element_set_.empty())
344 *elem = &disabled_element_set_.front();
348 auto iter = std::next(disabled_element_set_.iterator_to(**elem));
349 *elem = iter != std::end(disabled_element_set_) ? &*iter : nullptr;
353 return (*elem)->variable;
358 // if we modify the list between calls, normal version may loop forever
359 // this safe version ensures that we browse the list elements only once
360 Variable* Constraint::get_variable_safe(const Element** elem, const Element** nextelem, int* numelem) const
362 if (*elem == nullptr) {
363 *numelem = enabled_element_set_.size() + disabled_element_set_.size() - 1;
364 if (not enabled_element_set_.empty())
365 *elem = &enabled_element_set_.front();
366 else if (not disabled_element_set_.empty())
367 *elem = &disabled_element_set_.front();
378 // elem is not null, so we carry on
379 if ((*elem)->enabled_element_set_hook.is_linked()) {
380 // Look at enabled_element_set, and jump to disabled_element_set when finished
381 auto iter = std::next(enabled_element_set_.iterator_to(**elem));
382 if (iter != std::end(enabled_element_set_))
384 else if (not disabled_element_set_.empty())
385 *nextelem = &disabled_element_set_.front();
389 auto iter = std::next(disabled_element_set_.iterator_to(**elem));
390 *nextelem = iter != std::end(disabled_element_set_) ? &*iter : nullptr;
392 return (*elem)->variable;
397 static inline void saturated_constraints_update(double usage, int cnst_light_num, dyn_light_t& saturated_constraints,
400 xbt_assert(usage > 0, "Impossible");
402 if (*min_usage < 0 || *min_usage > usage) {
404 XBT_HERE(" min_usage=%f (cnst->remaining / cnst->usage =%f)", *min_usage, usage);
405 saturated_constraints.assign(1, cnst_light_num);
406 } else if (*min_usage == usage) {
407 saturated_constraints.emplace_back(cnst_light_num);
411 static inline void saturated_variable_set_update(ConstraintLight* cnst_light_tab,
412 const dyn_light_t& saturated_constraints, System* sys)
414 /* Add active variables (i.e. variables that need to be set) from the set of constraints to saturate
416 for (int const& saturated_cnst : saturated_constraints) {
417 ConstraintLight& cnst = cnst_light_tab[saturated_cnst];
418 for (Element const& elem : cnst.cnst->active_element_set_) {
419 xbt_assert(elem.variable->sharing_penalty_ > 0); // All elements of active_element_set should be active
420 if (elem.consumption_weight > 0 && not elem.variable->saturated_variable_set_hook_.is_linked())
421 sys->saturated_variable_set.push_back(*elem.variable);
426 template <class ElemList>
427 static void format_element_list(const ElemList& elem_list, s4u::Link::SharingPolicy sharing_policy, double& sum,
430 for (Element const& elem : elem_list) {
431 buf += std::to_string(elem.consumption_weight) + ".'" + std::to_string(elem.variable->rank_) + "'(" +
432 std::to_string(elem.variable->value_) + ")" +
433 (sharing_policy != s4u::Link::SharingPolicy::FATPIPE ? " + " : " , ");
434 if (sharing_policy != s4u::Link::SharingPolicy::FATPIPE)
435 sum += elem.consumption_weight * elem.variable->value_;
437 sum = std::max(sum, elem.consumption_weight * elem.variable->value_);
441 void System::print() const
443 std::string buf = std::string("MAX-MIN ( ");
445 /* Printing Objective */
446 for (Variable const& var : variable_set)
447 buf += "'" + std::to_string(var.rank_) + "'(" + std::to_string(var.sharing_penalty_) + ") ";
449 XBT_DEBUG("%20s", buf.c_str());
452 XBT_DEBUG("Constraints");
453 /* Printing Constraints */
454 for (Constraint const& cnst : active_constraint_set) {
456 // Show the enabled variables
458 buf += cnst.sharing_policy_ != s4u::Link::SharingPolicy::FATPIPE ? "(" : "max(";
459 format_element_list(cnst.enabled_element_set_, cnst.sharing_policy_, sum, buf);
460 // TODO: Adding disabled elements only for test compatibility, but do we really want them to be printed?
461 format_element_list(cnst.disabled_element_set_, cnst.sharing_policy_, sum, buf);
463 buf += "0) <= " + std::to_string(cnst.bound_) + " ('" + std::to_string(cnst.rank_) + "')";
465 if (cnst.sharing_policy_ == s4u::Link::SharingPolicy::FATPIPE) {
466 buf += " [MAX-Constraint]";
468 XBT_DEBUG("%s", buf.c_str());
470 xbt_assert(not double_positive(sum - cnst.bound_, cnst.bound_ * sg_maxmin_precision),
471 "Incorrect value (%f is not smaller than %f): %g", sum, cnst.bound_, sum - cnst.bound_);
474 XBT_DEBUG("Variables");
475 /* Printing Result */
476 for (Variable const& var : variable_set) {
477 if (var.bound_ > 0) {
478 XBT_DEBUG("'%d'(%f) : %f (<=%f)", var.rank_, var.sharing_penalty_, var.value_, var.bound_);
479 xbt_assert(not double_positive(var.value_ - var.bound_, var.bound_ * sg_maxmin_precision),
480 "Incorrect value (%f is not smaller than %f", var.value_, var.bound_);
482 XBT_DEBUG("'%d'(%f) : %f", var.rank_, var.sharing_penalty_, var.value_);
487 void System::lmm_solve()
490 XBT_IN("(sys=%p)", this);
491 /* Compute Usage and store the variables that reach the maximum. If selective_update_active is true, only
492 * constraints that changed are considered. Otherwise all constraints with active actions are considered.
494 if (selective_update_active)
495 lmm_solve(modified_constraint_set);
497 lmm_solve(active_constraint_set);
502 template <class CnstList> void System::lmm_solve(CnstList& cnst_list)
504 double min_usage = -1;
505 double min_bound = -1;
507 XBT_DEBUG("Active constraints : %zu", cnst_list.size());
508 /* Init: Only modified code portions: reset the value of active variables */
509 for (Constraint const& cnst : cnst_list) {
510 for (Element const& elem : cnst.enabled_element_set_) {
511 xbt_assert(elem.variable->sharing_penalty_ > 0.0);
512 elem.variable->value_ = 0.0;
516 ConstraintLight* cnst_light_tab = new ConstraintLight[cnst_list.size()]();
517 int cnst_light_num = 0;
518 dyn_light_t saturated_constraints;
520 for (Constraint& cnst : cnst_list) {
521 /* INIT: Collect constraints that actually need to be saturated (i.e remaining and usage are strictly positive)
522 * into cnst_light_tab. */
523 cnst.remaining_ = cnst.bound_;
524 if (not double_positive(cnst.remaining_, cnst.bound_ * sg_maxmin_precision))
527 for (Element& elem : cnst.enabled_element_set_) {
528 xbt_assert(elem.variable->sharing_penalty_ > 0);
529 if (elem.consumption_weight > 0) {
530 if (cnst.sharing_policy_ != s4u::Link::SharingPolicy::FATPIPE)
531 cnst.usage_ += elem.consumption_weight / elem.variable->sharing_penalty_;
532 else if (cnst.usage_ < elem.consumption_weight / elem.variable->sharing_penalty_)
533 cnst.usage_ = elem.consumption_weight / elem.variable->sharing_penalty_;
536 resource::Action* action = static_cast<resource::Action*>(elem.variable->id_);
537 if (modified_set_ && not action->is_within_modified_set())
538 modified_set_->push_back(*action);
541 XBT_DEBUG("Constraint '%d' usage: %f remaining: %f concurrency: %i<=%i<=%i", cnst.rank_, cnst.usage_,
542 cnst.remaining_, cnst.concurrency_current_, cnst.concurrency_maximum_, cnst.get_concurrency_limit());
543 /* Saturated constraints update */
545 if (cnst.usage_ > 0) {
546 cnst_light_tab[cnst_light_num].cnst = &cnst;
547 cnst.cnst_light_ = &cnst_light_tab[cnst_light_num];
548 cnst_light_tab[cnst_light_num].remaining_over_usage = cnst.remaining_ / cnst.usage_;
549 saturated_constraints_update(cnst_light_tab[cnst_light_num].remaining_over_usage, cnst_light_num,
550 saturated_constraints, &min_usage);
551 xbt_assert(not cnst.active_element_set_.empty(),
552 "There is no sense adding a constraint that has no active element!");
557 saturated_variable_set_update(cnst_light_tab, saturated_constraints, this);
559 /* Saturated variables update */
561 /* Fix the variables that have to be */
562 auto& var_list = saturated_variable_set;
563 for (Variable const& var : var_list) {
564 if (var.sharing_penalty_ <= 0.0)
566 /* First check if some of these variables could reach their upper bound and update min_bound accordingly. */
567 XBT_DEBUG("var=%d, var.bound=%f, var.penalty=%f, min_usage=%f, var.bound*var.penalty=%f", var.rank_, var.bound_,
568 var.sharing_penalty_, min_usage, var.bound_ * var.sharing_penalty_);
569 if ((var.bound_ > 0) && (var.bound_ * var.sharing_penalty_ < min_usage)) {
571 min_bound = var.bound_ * var.sharing_penalty_;
573 min_bound = std::min(min_bound, (var.bound_ * var.sharing_penalty_));
574 XBT_DEBUG("Updated min_bound=%f", min_bound);
578 while (not var_list.empty()) {
579 Variable& var = var_list.front();
581 // If no variable could reach its bound, deal iteratively the constraints usage ( at worst one constraint is
582 // saturated at each cycle)
583 var.value_ = min_usage / var.sharing_penalty_;
584 XBT_DEBUG("Setting var (%d) value to %f\n", var.rank_, var.value_);
586 // If there exist a variable that can reach its bound, only update it (and other with the same bound) for now.
587 if (double_equals(min_bound, var.bound_ * var.sharing_penalty_, sg_maxmin_precision)) {
588 var.value_ = var.bound_;
589 XBT_DEBUG("Setting %p (%d) value to %f\n", &var, var.rank_, var.value_);
591 // Variables which bound is different are not considered for this cycle, but they will be afterwards.
592 XBT_DEBUG("Do not consider %p (%d) \n", &var, var.rank_);
593 var_list.pop_front();
597 XBT_DEBUG("Min usage: %f, Var(%d).penalty: %f, Var(%d).value: %f ", min_usage, var.rank_, var.sharing_penalty_,
598 var.rank_, var.value_);
600 /* Update the usage of contraints where this variable is involved */
601 for (Element& elem : var.cnsts_) {
602 Constraint* cnst = elem.constraint;
603 if (cnst->sharing_policy_ != s4u::Link::SharingPolicy::FATPIPE) {
604 // Remember: shared constraints require that sum(elem.value * var.value) < cnst->bound
605 double_update(&(cnst->remaining_), elem.consumption_weight * var.value_, cnst->bound_ * sg_maxmin_precision);
606 double_update(&(cnst->usage_), elem.consumption_weight / var.sharing_penalty_, sg_maxmin_precision);
607 // If the constraint is saturated, remove it from the set of active constraints (light_tab)
608 if (not double_positive(cnst->usage_, sg_maxmin_precision) ||
609 not double_positive(cnst->remaining_, cnst->bound_ * sg_maxmin_precision)) {
610 if (cnst->cnst_light_) {
611 int index = (cnst->cnst_light_ - cnst_light_tab);
612 XBT_DEBUG("index: %d \t cnst_light_num: %d \t || usage: %f remaining: %f bound: %f ", index,
613 cnst_light_num, cnst->usage_, cnst->remaining_, cnst->bound_);
614 cnst_light_tab[index] = cnst_light_tab[cnst_light_num - 1];
615 cnst_light_tab[index].cnst->cnst_light_ = &cnst_light_tab[index];
617 cnst->cnst_light_ = nullptr;
620 if (cnst->cnst_light_) {
621 cnst->cnst_light_->remaining_over_usage = cnst->remaining_ / cnst->usage_;
624 elem.make_inactive();
626 // Remember: non-shared constraints only require that max(elem.value * var.value) < cnst->bound
628 elem.make_inactive();
629 for (Element& elem2 : cnst->enabled_element_set_) {
630 xbt_assert(elem2.variable->sharing_penalty_ > 0);
631 if (elem2.variable->value_ > 0)
633 if (elem2.consumption_weight > 0)
634 cnst->usage_ = std::max(cnst->usage_, elem2.consumption_weight / elem2.variable->sharing_penalty_);
636 // If the constraint is saturated, remove it from the set of active constraints (light_tab)
637 if (not double_positive(cnst->usage_, sg_maxmin_precision) ||
638 not double_positive(cnst->remaining_, cnst->bound_ * sg_maxmin_precision)) {
639 if (cnst->cnst_light_) {
640 int index = (cnst->cnst_light_ - cnst_light_tab);
641 XBT_DEBUG("index: %d \t cnst_light_num: %d \t || \t cnst: %p \t cnst->cnst_light: %p "
642 "\t cnst_light_tab: %p usage: %f remaining: %f bound: %f ",
643 index, cnst_light_num, cnst, cnst->cnst_light_, cnst_light_tab, cnst->usage_, cnst->remaining_,
645 cnst_light_tab[index] = cnst_light_tab[cnst_light_num - 1];
646 cnst_light_tab[index].cnst->cnst_light_ = &cnst_light_tab[index];
648 cnst->cnst_light_ = nullptr;
651 if (cnst->cnst_light_) {
652 cnst->cnst_light_->remaining_over_usage = cnst->remaining_ / cnst->usage_;
653 xbt_assert(not cnst->active_element_set_.empty(),
654 "Should not keep a maximum constraint that has no active"
655 " element! You want to check the maxmin precision and possible rounding effects.");
660 var_list.pop_front();
663 /* Find out which variables reach the maximum */
666 saturated_constraints.clear();
668 for (pos = 0; pos < cnst_light_num; pos++) {
669 xbt_assert(not cnst_light_tab[pos].cnst->active_element_set_.empty(),
670 "Cannot saturate more a constraint that has"
671 " no active element! You may want to change the maxmin precision (--cfg=maxmin/precision:<new_value>)"
672 " because of possible rounding effects.\n\tFor the record, the usage of this constraint is %g while "
673 "the maxmin precision to which it is compared is %g.\n\tThe usage of the previous constraint is %g.",
674 cnst_light_tab[pos].cnst->usage_, sg_maxmin_precision, cnst_light_tab[pos - 1].cnst->usage_);
675 saturated_constraints_update(cnst_light_tab[pos].remaining_over_usage, pos, saturated_constraints, &min_usage);
678 saturated_variable_set_update(cnst_light_tab, saturated_constraints, this);
680 } while (cnst_light_num > 0);
683 if (selective_update_active)
684 remove_all_modified_set();
686 if (XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug)) {
692 delete[] cnst_light_tab;
695 /** @brief Attribute the value bound to var->bound.
697 * @param var the Variable*
698 * @param bound the new bound to associate with var
700 * Makes var->bound equal to bound. Whenever this function is called a change is signed in the system. To
701 * avoid false system changing detection it is a good idea to test (bound != 0) before calling it.
703 void System::update_variable_bound(Variable* var, double bound)
708 if (not var->cnsts_.empty())
709 update_modified_set(var->cnsts_[0].constraint);
712 void Variable::initialize(resource::Action* id_value, double sharing_penalty, double bound_value,
713 int number_of_constraints, unsigned visited_value)
716 rank_ = next_rank_++;
717 cnsts_.reserve(number_of_constraints);
718 sharing_penalty_ = sharing_penalty;
719 staged_penalty_ = 0.0;
720 bound_ = bound_value;
721 concurrency_share_ = 1;
723 visited_ = visited_value;
726 xbt_assert(not variable_set_hook_.is_linked());
727 xbt_assert(not saturated_variable_set_hook_.is_linked());
730 int Variable::get_min_concurrency_slack() const
732 int minslack = std::numeric_limits<int>::max();
733 for (Element const& elem : cnsts_) {
734 int slack = elem.constraint->get_concurrency_slack();
735 if (slack < minslack) {
736 // This is only an optimization, to avoid looking at more constraints when slack is already zero
745 // Small remark: In this implementation of System::enable_var() and System::disable_var(), we will meet multiple times
746 // with var when running System::update_modified_set().
747 // A priori not a big performance issue, but we might do better by calling System::update_modified_set() within the for
748 // loops (after doing the first for enabling==1, and before doing the last for disabling==1)
749 void System::enable_var(Variable* var)
751 xbt_assert(not XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug) || var->can_enable());
753 var->sharing_penalty_ = var->staged_penalty_;
754 var->staged_penalty_ = 0;
756 // Enabling the variable, move var to list head. Subtlety is: here, we need to call update_modified_set AFTER
757 // moving at least one element of var.
759 simgrid::xbt::intrusive_erase(variable_set, *var);
760 variable_set.push_front(*var);
761 for (Element& elem : var->cnsts_) {
762 simgrid::xbt::intrusive_erase(elem.constraint->disabled_element_set_, elem);
763 elem.constraint->enabled_element_set_.push_front(elem);
764 elem.increase_concurrency();
766 if (not var->cnsts_.empty())
767 update_modified_set(var->cnsts_[0].constraint);
769 // When used within on_disabled_var, we would get an assertion fail, because transiently there can be variables
770 // that are staged and could be activated.
771 // Anyway, caller functions all call check_concurrency() in the end.
774 void System::disable_var(Variable* var)
776 xbt_assert(not var->staged_penalty_, "Staged penalty should have been cleared");
777 // Disabling the variable, move to var to list tail. Subtlety is: here, we need to call update_modified_set
778 // BEFORE moving the last element of var.
779 simgrid::xbt::intrusive_erase(variable_set, *var);
780 variable_set.push_back(*var);
781 if (not var->cnsts_.empty())
782 update_modified_set(var->cnsts_[0].constraint);
783 for (Element& elem : var->cnsts_) {
784 simgrid::xbt::intrusive_erase(elem.constraint->enabled_element_set_, elem);
785 elem.constraint->disabled_element_set_.push_back(elem);
786 if (elem.active_element_set_hook.is_linked())
787 simgrid::xbt::intrusive_erase(elem.constraint->active_element_set_, elem);
788 elem.decrease_concurrency();
791 var->sharing_penalty_ = 0.0;
792 var->staged_penalty_ = 0.0;
797 /* /brief Find variables that can be enabled and enable them.
799 * Assuming that the variable has already been removed from non-zero penalties
800 * Can we find a staged variable to add?
801 * If yes, check that none of the constraints that this variable is involved in is at the limit of its concurrency
802 * And then add it to enabled variables
804 void System::on_disabled_var(Constraint* cnstr)
806 if (cnstr->get_concurrency_limit() < 0)
809 int numelem = cnstr->disabled_element_set_.size();
813 Element* elem = &cnstr->disabled_element_set_.front();
815 // Cannot use foreach loop, because System::enable_var() will modify disabled_element_set.. within the loop
816 while (numelem-- && elem) {
819 if (elem->disabled_element_set_hook.is_linked()) {
820 auto iter = std::next(cnstr->disabled_element_set_.iterator_to(*elem));
821 nextelem = iter != std::end(cnstr->disabled_element_set_) ? &*iter : nullptr;
826 if (elem->variable->staged_penalty_ > 0 && elem->variable->can_enable()) {
827 // Found a staged variable
828 // TODOLATER: Add random timing function to model reservation protocol fuzziness? Then how to make sure that
829 // staged variables will eventually be called?
830 enable_var(elem->variable);
833 xbt_assert(cnstr->concurrency_current_ <= cnstr->get_concurrency_limit(), "Concurrency overflow!");
834 if (cnstr->concurrency_current_ == cnstr->get_concurrency_limit())
840 // We could get an assertion fail, because transiently there can be variables that are staged and could be activated.
841 // And we need to go through all constraints of the disabled var before getting back a coherent state.
842 // Anyway, caller functions all call check_concurrency() in the end.
845 /** @brief update the penalty of a variable (disable it by passing 0 as a penalty) */
846 void System::update_variable_penalty(Variable* var, double penalty)
848 xbt_assert(penalty >= 0, "Variable penalty should not be negative!");
850 if (penalty == var->sharing_penalty_)
853 int enabling_var = (penalty > 0 && var->sharing_penalty_ <= 0);
854 int disabling_var = (penalty <= 0 && var->sharing_penalty_ > 0);
856 XBT_IN("(sys=%p, var=%p, penalty=%f)", this, var, penalty);
860 // Are we enabling this variable?
862 var->staged_penalty_ = penalty;
863 int minslack = var->get_min_concurrency_slack();
864 if (minslack < var->concurrency_share_) {
865 XBT_DEBUG("Staging var (instead of enabling) because min concurrency slack %i, with penalty %f and concurrency"
867 minslack, penalty, var->concurrency_share_);
870 XBT_DEBUG("Enabling var with min concurrency slack %i", minslack);
872 } else if (disabling_var) {
875 var->sharing_penalty_ = penalty;
883 void System::update_constraint_bound(Constraint* cnst, double bound)
886 update_modified_set(cnst);
887 cnst->bound_ = bound;
890 /** @brief Update the constraint set propagating recursively to other constraints so the system should not be entirely
893 * @param cnst the Constraint* affected by the change
895 * A recursive algorithm to optimize the system recalculation selecting only constraints that have changed. Each
896 * constraint change is propagated to the list of constraints for each variable.
898 void System::update_modified_set_rec(Constraint* cnst)
900 for (Element const& elem : cnst->enabled_element_set_) {
901 Variable* var = elem.variable;
902 for (Element const& elem2 : var->cnsts_) {
903 if (var->visited_ == visited_counter_)
905 if (elem2.constraint != cnst && not elem2.constraint->modified_constraint_set_hook_.is_linked()) {
906 modified_constraint_set.push_back(*elem2.constraint);
907 update_modified_set_rec(elem2.constraint);
910 // var will be ignored in later visits as long as sys->visited_counter does not move
911 var->visited_ = visited_counter_;
915 void System::update_modified_set(Constraint* cnst)
917 /* nothing to do if selective update isn't active */
918 if (selective_update_active && not cnst->modified_constraint_set_hook_.is_linked()) {
919 modified_constraint_set.push_back(*cnst);
920 update_modified_set_rec(cnst);
924 void System::remove_all_modified_set()
926 // We cleverly un-flag all variables just by incrementing visited_counter
927 // In effect, the var->visited value will no more be equal to visited counter
928 // To be clean, when visited counter has wrapped around, we force these var->visited values so that variables that
929 // were in the modified a long long time ago are not wrongly skipped here, which would lead to very nasty bugs
930 // (i.e. not readibily reproducible, and requiring a lot of run time before happening).
931 if (++visited_counter_ == 1) {
932 /* the counter wrapped around, reset each variable->visited */
933 for (Variable& var : variable_set)
936 modified_constraint_set.clear();
940 * Returns resource load (in flop per second, or byte per second, or similar)
942 * If the resource is shared (the default case), the load is sum of resource usage made by
943 * every variables located on this resource.
945 * If the resource is not shared (ie in FATPIPE mode), then the load is the max (not the sum)
946 * of all resource usages located on this resource.
948 double Constraint::get_usage() const
951 if (sharing_policy_ != s4u::Link::SharingPolicy::FATPIPE) {
952 for (Element const& elem : enabled_element_set_)
953 if (elem.consumption_weight > 0)
954 result += elem.consumption_weight * elem.variable->value_;
956 for (Element const& elem : enabled_element_set_)
957 if (elem.consumption_weight > 0)
958 result = std::max(result, elem.consumption_weight * elem.variable->value_);
963 int Constraint::get_variable_amount() const
965 return std::count_if(std::begin(enabled_element_set_), std::end(enabled_element_set_),
966 [](const Element& elem) { return elem.consumption_weight > 0; });