1 /* Copyright (c) 2004-2022. 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/fair_bottleneck.hpp"
7 #include "src/kernel/lmm/maxmin.hpp"
8 #if SIMGRID_HAVE_EIGEN3
9 #include "src/kernel/lmm/bmf.hpp"
11 #include <boost/core/demangle.hpp>
14 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(ker_lmm, kernel, "Kernel Linear Max-Min solver");
16 double sg_maxmin_precision = 1E-5; /* Change this with --cfg=maxmin/precision:VALUE */
17 double sg_surf_precision = 1E-9; /* Change this with --cfg=surf/precision:VALUE */
18 int sg_concurrency_limit = -1; /* Change this with --cfg=maxmin/concurrency-limit:VALUE */
24 int Variable::next_rank_ = 1;
25 int Constraint::next_rank_ = 1;
27 Element::Element(Constraint* constraint, Variable* variable, double cweight)
28 : constraint(constraint), variable(variable), consumption_weight(cweight), max_consumption_weight(cweight)
32 int Element::get_concurrency() const
34 // Ignore element with weight less than one (e.g. cross-traffic)
35 return (consumption_weight >= 1) ? 1 : 0;
36 // There are other alternatives, but they will change the behavior of the model..
37 // So do not use it unless you want to make a new model.
38 // If you do, remember to change the variables concurrency share to reflect it.
39 // Potential examples are:
40 // return (elem->weight>0)?1:0;//Include element as soon as weight is non-zero
41 // return (int)ceil(elem->weight);//Include element as the rounded-up integer value of the element weight
44 void Element::decrease_concurrency()
46 xbt_assert(constraint->concurrency_current_ >= get_concurrency());
47 constraint->concurrency_current_ -= get_concurrency();
50 void Element::increase_concurrency(bool check_limit)
52 constraint->concurrency_current_ += get_concurrency();
54 if (constraint->concurrency_current_ > constraint->concurrency_maximum_)
55 constraint->concurrency_maximum_ = constraint->concurrency_current_;
57 xbt_assert(not check_limit || constraint->get_concurrency_limit() < 0 ||
58 constraint->concurrency_current_ <= constraint->get_concurrency_limit(),
59 "Concurrency limit overflow!");
62 System* System::build(const std::string& solver_name, bool selective_update)
64 System* system = nullptr;
65 if (solver_name == "bmf") {
66 #if SIMGRID_HAVE_EIGEN3
67 system = new BmfSystem(selective_update);
69 } else if (solver_name == "fairbottleneck") {
70 system = new FairBottleneck(selective_update);
72 system = new MaxMin(selective_update);
77 void System::validate_solver(const std::string& solver_name)
79 static const std::vector<std::string> opts{"bmf", "maxmin", "fairbottleneck"};
80 if (solver_name == "bmf") {
81 #if !SIMGRID_HAVE_EIGEN3
82 xbt_die("Cannot use the BMF solver without installing Eigen3.");
85 if (std::find(opts.begin(), opts.end(), solver_name) == std::end(opts)) {
86 xbt_die("Invalid system solver, it should be one of: \"maxmin\", \"fairbottleneck\" or \"bmf\"");
90 void System::check_concurrency() const
92 // These checks are very expensive, so do them only if we want to debug SURF LMM
93 if (not XBT_LOG_ISENABLED(ker_lmm, xbt_log_priority_debug))
96 for (Constraint const& cnst : constraint_set) {
98 for (Element const& elem : cnst.enabled_element_set_) {
99 xbt_assert(elem.variable->sharing_penalty_ > 0);
100 concurrency += elem.get_concurrency();
103 for (Element const& elem : cnst.disabled_element_set_) {
104 // We should have staged variables only if concurrency is reached in some constraint
105 xbt_assert(cnst.get_concurrency_limit() < 0 || elem.variable->staged_sharing_penalty_ == 0 ||
106 elem.variable->get_min_concurrency_slack() == 0,
107 "should not have staged variable!");
110 xbt_assert(cnst.get_concurrency_limit() < 0 || cnst.get_concurrency_limit() >= concurrency,
111 "concurrency check failed!");
112 xbt_assert(cnst.concurrency_current_ == concurrency, "concurrency_current is out-of-date!");
115 // Check that for each variable, all corresponding elements are in the same state (i.e. same element sets)
116 for (Variable const& var : variable_set) {
117 if (var.cnsts_.empty())
120 const Element& elem = var.cnsts_[0];
121 bool belong_to_enabled = elem.enabled_element_set_hook.is_linked();
122 bool belong_to_disabled = elem.disabled_element_set_hook.is_linked();
123 bool belong_to_active = elem.active_element_set_hook.is_linked();
125 for (Element const& elem2 : var.cnsts_) {
126 xbt_assert(belong_to_enabled == elem2.enabled_element_set_hook.is_linked(),
127 "Variable inconsistency (1): enabled_element_set");
128 xbt_assert(belong_to_disabled == elem2.disabled_element_set_hook.is_linked(),
129 "Variable inconsistency (2): disabled_element_set");
130 xbt_assert(belong_to_active == elem2.active_element_set_hook.is_linked(),
131 "Variable inconsistency (3): active_element_set");
136 void System::var_free(Variable* var)
138 XBT_IN("(sys=%p, var=%p)", this, var);
141 // TODOLATER Can do better than that by leaving only the variable in only one enabled_element_set, call
142 // update_modified_set, and then remove it..
143 update_modified_cnst_set_from_variable(var);
145 for (Element& elem : var->cnsts_) {
146 if (var->sharing_penalty_ > 0)
147 elem.decrease_concurrency();
148 if (elem.enabled_element_set_hook.is_linked())
149 simgrid::xbt::intrusive_erase(elem.constraint->enabled_element_set_, elem);
150 if (elem.disabled_element_set_hook.is_linked())
151 simgrid::xbt::intrusive_erase(elem.constraint->disabled_element_set_, elem);
152 if (elem.active_element_set_hook.is_linked())
153 simgrid::xbt::intrusive_erase(elem.constraint->active_element_set_, elem);
154 if (elem.constraint->enabled_element_set_.empty() && elem.constraint->disabled_element_set_.empty())
155 make_constraint_inactive(elem.constraint);
157 on_disabled_var(elem.constraint);
164 xbt_mallocator_release(variable_mallocator_, var);
168 System::System(bool selective_update) : selective_update_active(selective_update)
170 XBT_DEBUG("Setting selective_update_active flag to %d", selective_update_active);
172 if (selective_update)
173 modified_set_ = std::make_unique<kernel::resource::Action::ModifiedSet>();
178 while (Variable* var = extract_variable()) {
179 std::string demangled = boost::core::demangle(var->id_ ? typeid(*var->id_).name() : "(unidentified)");
180 XBT_WARN("Probable bug: a %s variable (#%d) not removed before the LMM system destruction.", demangled.c_str(),
184 while (Constraint* cnst = extract_constraint())
187 xbt_mallocator_free(variable_mallocator_);
190 void System::cnst_free(Constraint* cnst)
192 make_constraint_inactive(cnst);
196 Constraint::Constraint(resource::Resource* id_value, double bound_value) : bound_(bound_value), id_(id_value)
198 rank_ = next_rank_++;
201 Constraint* System::constraint_new(resource::Resource* id, double bound_value)
203 auto* cnst = new Constraint(id, bound_value);
204 insert_constraint(cnst);
208 void* System::variable_mallocator_new_f()
213 void System::variable_mallocator_free_f(void* var)
215 delete static_cast<Variable*>(var);
218 Variable* System::variable_new(resource::Action* id, double sharing_penalty, double bound, size_t number_of_constraints)
220 XBT_IN("(sys=%p, id=%p, penalty=%f, bound=%f, num_cons =%zu)", this, id, sharing_penalty, bound,
221 number_of_constraints);
223 auto* var = static_cast<Variable*>(xbt_mallocator_get(variable_mallocator_));
224 var->initialize(id, sharing_penalty, bound, number_of_constraints, visited_counter_ - 1);
225 if (sharing_penalty > 0)
226 variable_set.push_front(*var);
228 variable_set.push_back(*var);
230 XBT_OUT(" returns %p", var);
234 void System::variable_free(Variable* var)
236 remove_variable(var);
240 void System::variable_free_all()
242 while (Variable* var = extract_variable())
246 Element& System::expand_create_elem(Constraint* cnst, Variable* var, double consumption_weight)
248 xbt_assert(var->cnsts_.size() < var->cnsts_.capacity(), "Too much constraints");
250 var->cnsts_.emplace_back(cnst, var, consumption_weight);
251 Element& elem = var->cnsts_.back();
253 if (var->sharing_penalty_ != 0.0) {
254 elem.constraint->enabled_element_set_.push_front(elem);
256 elem.constraint->disabled_element_set_.push_back(elem);
258 if (elem.consumption_weight > 0 || var->sharing_penalty_ > 0) {
259 make_constraint_active(cnst);
264 Element& System::expand_add_to_elem(Element& elem, const Constraint* cnst, double consumption_weight) const
266 elem.max_consumption_weight = std::max(elem.max_consumption_weight, consumption_weight);
267 if (cnst->sharing_policy_ != Constraint::SharingPolicy::FATPIPE)
268 elem.consumption_weight += consumption_weight;
270 elem.consumption_weight = std::max(elem.consumption_weight, consumption_weight);
274 void System::expand(Constraint* cnst, Variable* var, double consumption_weight)
279 std::find_if(begin(var->cnsts_), end(var->cnsts_), [&cnst](Element const& x) { return x.constraint == cnst; });
280 if (elem_it != end(var->cnsts_) && var->sharing_penalty_ != 0.0) {
281 /* before changing it, decreases concurrency on constraint, it'll be added back later */
282 elem_it->decrease_concurrency();
284 Element& elem = elem_it != end(var->cnsts_) ? expand_add_to_elem(*elem_it, cnst, consumption_weight)
285 : expand_create_elem(cnst, var, consumption_weight);
287 // Check if we need to disable the variable
288 if (var->sharing_penalty_ != 0) {
289 /* increase concurrency in constraint that this element uses.
290 * as we don't check if constraint has reached its limit before increasing,
291 * we can't check the correct state at increase_concurrency, anyway
292 * it'll check if the slack is smaller than 0 just below */
293 elem.increase_concurrency(false);
294 if (cnst->get_concurrency_slack() < 0) {
295 double penalty = var->sharing_penalty_;
297 for (Element const& elem2 : var->cnsts_)
298 on_disabled_var(elem2.constraint);
299 var->staged_sharing_penalty_ = penalty;
300 xbt_assert(not var->sharing_penalty_);
304 /* update modified constraint set accordingly */
305 if (elem.consumption_weight > 0 || var->sharing_penalty_ > 0)
306 update_modified_cnst_set(cnst);
311 Variable* Constraint::get_variable(const Element** elem) const
313 if (*elem == nullptr) {
314 // That is the first call, pick the first element among enabled_element_set (or disabled_element_set if
315 // enabled_element_set is empty)
316 if (not enabled_element_set_.empty())
317 *elem = &enabled_element_set_.front();
318 else if (not disabled_element_set_.empty())
319 *elem = &disabled_element_set_.front();
323 // elem is not null, so we carry on
324 if ((*elem)->enabled_element_set_hook.is_linked()) {
325 // Look at enabled_element_set, and jump to disabled_element_set when finished
326 auto iter = std::next(enabled_element_set_.iterator_to(**elem));
327 if (iter != std::end(enabled_element_set_))
329 else if (not disabled_element_set_.empty())
330 *elem = &disabled_element_set_.front();
334 auto iter = std::next(disabled_element_set_.iterator_to(**elem));
335 *elem = iter != std::end(disabled_element_set_) ? &*iter : nullptr;
339 return (*elem)->variable;
344 // if we modify the list between calls, normal version may loop forever
345 // this safe version ensures that we browse the list elements only once
346 Variable* Constraint::get_variable_safe(const Element** elem, const Element** nextelem, size_t* numelem) const
348 if (*elem == nullptr) {
349 *numelem = enabled_element_set_.size() + disabled_element_set_.size() - 1;
350 if (not enabled_element_set_.empty())
351 *elem = &enabled_element_set_.front();
352 else if (not disabled_element_set_.empty())
353 *elem = &disabled_element_set_.front();
364 // elem is not null, so we carry on
365 if ((*elem)->enabled_element_set_hook.is_linked()) {
366 // Look at enabled_element_set, and jump to disabled_element_set when finished
367 auto iter = std::next(enabled_element_set_.iterator_to(**elem));
368 if (iter != std::end(enabled_element_set_))
370 else if (not disabled_element_set_.empty())
371 *nextelem = &disabled_element_set_.front();
375 auto iter = std::next(disabled_element_set_.iterator_to(**elem));
376 *nextelem = iter != std::end(disabled_element_set_) ? &*iter : nullptr;
378 return (*elem)->variable;
383 template <class ElemList>
384 static void format_element_list(const ElemList& elem_list, Constraint::SharingPolicy sharing_policy, double& sum,
387 for (Element const& elem : elem_list) {
388 buf += std::to_string(elem.consumption_weight) + ".'" + std::to_string(elem.variable->rank_) + "'(" +
389 std::to_string(elem.variable->value_) + ")" +
390 (sharing_policy != Constraint::SharingPolicy::FATPIPE ? " + " : " , ");
391 if (sharing_policy != Constraint::SharingPolicy::FATPIPE)
392 sum += elem.consumption_weight * elem.variable->value_;
394 sum = std::max(sum, elem.consumption_weight * elem.variable->value_);
398 void System::print() const
400 std::string buf = "MAX-MIN ( ";
402 /* Printing Objective */
403 for (Variable const& var : variable_set)
404 buf += "'" + std::to_string(var.rank_) + "'(" + std::to_string(var.sharing_penalty_) + ") ";
406 XBT_DEBUG("%20s", buf.c_str());
409 XBT_DEBUG("Constraints");
410 /* Printing Constraints */
411 for (Constraint const& cnst : active_constraint_set) {
413 // Show the enabled variables
415 buf += cnst.sharing_policy_ != Constraint::SharingPolicy::FATPIPE ? "(" : "max(";
416 format_element_list(cnst.enabled_element_set_, cnst.sharing_policy_, sum, buf);
417 // TODO: Adding disabled elements only for test compatibility, but do we really want them to be printed?
418 format_element_list(cnst.disabled_element_set_, cnst.sharing_policy_, sum, buf);
420 buf += "0) <= " + std::to_string(cnst.bound_) + " ('" + std::to_string(cnst.rank_) + "')";
422 if (cnst.sharing_policy_ == Constraint::SharingPolicy::FATPIPE) {
423 buf += " [MAX-Constraint]";
425 XBT_DEBUG("%s", buf.c_str());
427 xbt_assert(not double_positive(sum - cnst.bound_, cnst.bound_ * sg_maxmin_precision),
428 "Incorrect value (%f is not smaller than %f): %g", sum, cnst.bound_, sum - cnst.bound_);
431 XBT_DEBUG("Variables");
432 /* Printing Result */
433 for (Variable const& var : variable_set) {
434 if (var.bound_ > 0) {
435 XBT_DEBUG("'%d'(%f) : %f (<=%f)", var.rank_, var.sharing_penalty_, var.value_, var.bound_);
436 xbt_assert(not double_positive(var.value_ - var.bound_, var.bound_ * sg_maxmin_precision),
437 "Incorrect value (%f is not smaller than %f", var.value_, var.bound_);
439 XBT_DEBUG("'%d'(%f) : %f", var.rank_, var.sharing_penalty_, var.value_);
444 resource::Action::ModifiedSet* System::get_modified_action_set() const
446 return modified_set_.get();
457 if (selective_update_active) {
458 /* update list of modified variables */
459 for (const Constraint& cnst : modified_constraint_set) {
460 for (const Element& elem : cnst.enabled_element_set_) {
461 if (elem.consumption_weight > 0) {
462 resource::Action* action = elem.variable->id_;
463 if (not action->is_within_modified_set())
464 modified_set_->push_back(*action);
468 /* clear list of modified constraint */
469 remove_all_modified_cnst_set();
472 if (XBT_LOG_ISENABLED(ker_lmm, xbt_log_priority_debug)) {
479 /** @brief Attribute the value bound to var->bound.
481 * @param var the Variable*
482 * @param bound the new bound to associate with var
484 * Makes var->bound equal to bound. Whenever this function is called a change is signed in the system. To
485 * avoid false system changing detection it is a good idea to test (bound != 0) before calling it.
487 void System::update_variable_bound(Variable* var, double bound)
492 if (not var->cnsts_.empty()) {
493 for (Element const& elem : var->cnsts_) {
494 update_modified_cnst_set(elem.constraint);
499 void Variable::initialize(resource::Action* id_value, double sharing_penalty, double bound_value,
500 size_t number_of_constraints, unsigned visited_value)
503 rank_ = next_rank_++;
504 cnsts_.reserve(number_of_constraints);
505 sharing_penalty_ = sharing_penalty;
506 staged_sharing_penalty_ = 0.0;
507 bound_ = bound_value;
509 visited_ = visited_value;
512 xbt_assert(not variable_set_hook_.is_linked());
513 xbt_assert(not saturated_variable_set_hook_.is_linked());
516 int Variable::get_min_concurrency_slack() const
518 int minslack = std::numeric_limits<int>::max();
519 for (Element const& elem : cnsts_) {
520 int slack = elem.constraint->get_concurrency_slack();
521 if (slack < minslack) {
522 // This is only an optimization, to avoid looking at more constraints when slack is already zero
531 // Small remark: In this implementation of System::enable_var() and System::disable_var(), we will meet multiple times
532 // with var when running System::update_modified_cnst_set().
533 // A priori not a big performance issue, but we might do better by calling System::update_modified_cnst_set() within the
534 // for loops (after doing the first for enabling==1, and before doing the last for disabling==1)
535 void System::enable_var(Variable* var)
537 xbt_assert(not XBT_LOG_ISENABLED(ker_lmm, xbt_log_priority_debug) || var->can_enable());
539 var->sharing_penalty_ = var->staged_sharing_penalty_;
540 var->staged_sharing_penalty_ = 0;
542 // Enabling the variable, move var to list head. Subtlety is: here, we need to call update_modified_cnst_set AFTER
543 // moving at least one element of var.
545 simgrid::xbt::intrusive_erase(variable_set, *var);
546 variable_set.push_front(*var);
547 for (Element& elem : var->cnsts_) {
548 simgrid::xbt::intrusive_erase(elem.constraint->disabled_element_set_, elem);
549 elem.constraint->enabled_element_set_.push_front(elem);
550 elem.increase_concurrency();
552 update_modified_cnst_set_from_variable(var);
554 // When used within on_disabled_var, we would get an assertion fail, because transiently there can be variables
555 // that are staged and could be activated.
556 // Anyway, caller functions all call check_concurrency() in the end.
559 void System::disable_var(Variable* var)
561 xbt_assert(not var->staged_sharing_penalty_, "Staged penalty should have been cleared");
562 // Disabling the variable, move to var to list tail. Subtlety is: here, we need to call update_modified_cnst_set
563 // BEFORE moving the last element of var.
564 simgrid::xbt::intrusive_erase(variable_set, *var);
565 variable_set.push_back(*var);
566 update_modified_cnst_set_from_variable(var);
567 for (Element& elem : var->cnsts_) {
568 simgrid::xbt::intrusive_erase(elem.constraint->enabled_element_set_, elem);
569 elem.constraint->disabled_element_set_.push_back(elem);
570 if (elem.active_element_set_hook.is_linked())
571 simgrid::xbt::intrusive_erase(elem.constraint->active_element_set_, elem);
572 elem.decrease_concurrency();
575 var->sharing_penalty_ = 0.0;
576 var->staged_sharing_penalty_ = 0.0;
581 /* /brief Find variables that can be enabled and enable them.
583 * Assuming that the variable has already been removed from non-zero penalties
584 * Can we find a staged variable to add?
585 * If yes, check that none of the constraints that this variable is involved in is at the limit of its concurrency
586 * And then add it to enabled variables
588 void System::on_disabled_var(Constraint* cnstr)
590 if (cnstr->get_concurrency_limit() < 0)
593 size_t numelem = cnstr->disabled_element_set_.size();
597 Element* elem = &cnstr->disabled_element_set_.front();
599 // Cannot use foreach loop, because System::enable_var() will modify disabled_element_set.. within the loop
600 while (numelem-- && elem) {
602 if (elem->disabled_element_set_hook.is_linked()) {
603 auto iter = std::next(cnstr->disabled_element_set_.iterator_to(*elem));
604 nextelem = iter != std::end(cnstr->disabled_element_set_) ? &*iter : nullptr;
609 if (elem->variable->staged_sharing_penalty_ > 0 && elem->variable->can_enable()) {
610 // Found a staged variable
611 // TODOLATER: Add random timing function to model reservation protocol fuzziness? Then how to make sure that
612 // staged variables will eventually be called?
613 enable_var(elem->variable);
616 xbt_assert(cnstr->concurrency_current_ <= cnstr->get_concurrency_limit(), "Concurrency overflow!");
617 if (cnstr->concurrency_current_ == cnstr->get_concurrency_limit())
623 // We could get an assertion fail, because transiently there can be variables that are staged and could be activated.
624 // And we need to go through all constraints of the disabled var before getting back a coherent state.
625 // Anyway, caller functions all call check_concurrency() in the end.
628 /** @brief update the penalty of a variable (disable it by passing 0 as a penalty) */
629 void System::update_variable_penalty(Variable* var, double penalty)
631 xbt_assert(penalty >= 0, "Variable penalty should not be negative!");
632 if (penalty == var->sharing_penalty_)
635 bool enabling_var = (penalty > 0 && var->sharing_penalty_ <= 0);
636 bool disabling_var = (penalty <= 0 && var->sharing_penalty_ > 0);
638 XBT_IN("(sys=%p, var=%p, var->sharing_penalty = %f, penalty=%f)", this, var, var->sharing_penalty_, penalty);
642 // Are we enabling this variable?
644 var->staged_sharing_penalty_ = penalty;
645 int minslack = var->get_min_concurrency_slack();
647 XBT_DEBUG("Staging var (instead of enabling) because min concurrency slack is 0");
650 XBT_DEBUG("Enabling var with min concurrency slack %i", minslack);
652 } else if (disabling_var) {
655 var->sharing_penalty_ = penalty;
656 update_modified_cnst_set_from_variable(var);
664 void System::update_constraint_bound(Constraint* cnst, double bound)
667 update_modified_cnst_set(cnst);
668 cnst->bound_ = bound;
671 /** @brief Update the constraint set propagating recursively to other constraints so the system should not be entirely
674 * @param cnst the Constraint* affected by the change
676 * A recursive algorithm to optimize the system recalculation selecting only constraints that have changed. Each
677 * constraint change is propagated to the list of constraints for each variable.
679 void System::update_modified_cnst_set_rec(const Constraint* cnst)
681 for (Element const& elem : cnst->enabled_element_set_) {
682 Variable* var = elem.variable;
683 for (Element const& elem2 : var->cnsts_) {
684 if (var->visited_ == visited_counter_)
686 if (elem2.constraint != cnst && not elem2.constraint->modified_constraint_set_hook_.is_linked()) {
687 modified_constraint_set.push_back(*elem2.constraint);
688 update_modified_cnst_set_rec(elem2.constraint);
691 // var will be ignored in later visits as long as sys->visited_counter does not move
692 var->visited_ = visited_counter_;
696 void System::update_modified_cnst_set_from_variable(const Variable* var)
698 /* nothing to update in these cases:
699 * - selective update not active, all variables are active
700 * - variable doesn't use any constraint
701 * - variable is disabled (sharing penalty <= 0): we iterate only through the enabled_variables in
702 * update_modified_cnst_set_rec */
703 if (not selective_update_active || var->cnsts_.empty() || var->sharing_penalty_ <= 0)
706 /* Normally, if the conditions above are true, specially variable is enabled, we can call
707 * modified_set over the first contraint only, since the recursion in update_modified_cnst_set_rec
708 * will iterate over the other constraints of this variable */
709 update_modified_cnst_set(var->cnsts_[0].constraint);
712 void System::update_modified_cnst_set(Constraint* cnst)
714 /* nothing to do if selective update isn't active */
715 if (selective_update_active && not cnst->modified_constraint_set_hook_.is_linked()) {
716 modified_constraint_set.push_back(*cnst);
717 update_modified_cnst_set_rec(cnst);
721 void System::remove_all_modified_cnst_set()
723 // We cleverly un-flag all variables just by incrementing visited_counter
724 // In effect, the var->visited value will no more be equal to visited counter
725 // To be clean, when visited counter has wrapped around, we force these var->visited values so that variables that
726 // were in the modified a long long time ago are not wrongly skipped here, which would lead to very nasty bugs
727 // (i.e. not readily reproducible, and requiring a lot of run time before happening).
728 if (++visited_counter_ == 1) {
729 /* the counter wrapped around, reset each variable->visited */
730 for (Variable& var : variable_set)
733 modified_constraint_set.clear();
737 * Returns resource load (in flop per second, or byte per second, or similar)
739 * If the resource is shared (the default case), the load is sum of resource usage made by
740 * every variables located on this resource.
742 * If the resource is not shared (ie in FATPIPE mode), then the load is the max (not the sum)
743 * of all resource usages located on this resource.
745 double Constraint::get_usage() const
748 if (sharing_policy_ != SharingPolicy::FATPIPE) {
749 for (Element const& elem : enabled_element_set_)
750 if (elem.consumption_weight > 0)
751 result += elem.consumption_weight * elem.variable->value_;
753 for (Element const& elem : enabled_element_set_)
754 if (elem.consumption_weight > 0)
755 result = std::max(result, elem.consumption_weight * elem.variable->value_);
760 void Constraint::set_sharing_policy(SharingPolicy policy, const s4u::NonLinearResourceCb& cb)
762 xbt_assert(policy == SharingPolicy::NONLINEAR || not cb,
763 "Invalid sharing policy for constraint. Callback should be used with NONLINEAR sharing policy");
764 sharing_policy_ = policy;
765 dyn_constraint_cb_ = cb;
769 } // namespace kernel
770 } // namespace simgrid