1 /* Copyright (c) 2004-2023. 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 */
20 namespace simgrid::kernel::lmm {
22 int Variable::next_rank_ = 1;
23 int Constraint::next_rank_ = 1;
25 Element::Element(Constraint* constraint, Variable* variable, double cweight)
26 : constraint(constraint), variable(variable), consumption_weight(cweight), max_consumption_weight(cweight)
30 int Element::get_concurrency() const
32 // just to try having the computation of the concurrency
33 if (constraint->get_sharing_policy() == Constraint::SharingPolicy::WIFI) {
37 // Ignore element with weight less than one (e.g. cross-traffic)
38 return (consumption_weight >= 1) ? 1 : 0;
39 // There are other alternatives, but they will change the behavior of the model..
40 // So do not use it unless you want to make a new model.
41 // If you do, remember to change the variables concurrency share to reflect it.
42 // Potential examples are:
43 // return (elem->weight>0)?1:0;//Include element as soon as weight is non-zero
44 // return (int)ceil(elem->weight);//Include element as the rounded-up integer value of the element weight
47 void Element::decrease_concurrency()
49 xbt_assert(constraint->concurrency_current_ >= get_concurrency());
50 constraint->concurrency_current_ -= get_concurrency();
53 void Element::increase_concurrency(bool check_limit)
55 constraint->concurrency_current_ += get_concurrency();
57 if (constraint->concurrency_current_ > constraint->concurrency_maximum_)
58 constraint->concurrency_maximum_ = constraint->concurrency_current_;
60 xbt_assert(not check_limit || constraint->get_concurrency_limit() < 0 ||
61 constraint->concurrency_current_ <= constraint->get_concurrency_limit(),
62 "Concurrency limit overflow!");
65 System* System::build(std::string_view solver_name, bool selective_update)
67 System* system = nullptr;
68 if (solver_name == "bmf") {
69 #if SIMGRID_HAVE_EIGEN3
70 system = new BmfSystem(selective_update);
72 } else if (solver_name == "fairbottleneck") {
73 system = new FairBottleneck(selective_update);
75 system = new MaxMin(selective_update);
80 void System::validate_solver(const std::string& solver_name)
82 static const std::vector<std::string> opts{"bmf", "maxmin", "fairbottleneck"};
83 if (solver_name == "bmf") {
84 #if !SIMGRID_HAVE_EIGEN3
85 xbt_die("Cannot use the BMF solver without installing Eigen3.");
88 if (std::find(opts.begin(), opts.end(), solver_name) == std::end(opts)) {
89 xbt_die("Invalid system solver, it should be one of: \"maxmin\", \"fairbottleneck\" or \"bmf\"");
93 void System::check_concurrency() const
95 // These checks are very expensive, so do them only if we want to debug SURF LMM
96 if (not XBT_LOG_ISENABLED(ker_lmm, xbt_log_priority_debug))
99 for (Constraint const& cnst : constraint_set) {
101 for (Element const& elem : cnst.enabled_element_set_) {
102 xbt_assert(elem.variable->sharing_penalty_ > 0);
103 concurrency += elem.get_concurrency();
106 for (Element const& elem : cnst.disabled_element_set_) {
107 // We should have staged variables only if concurrency is reached in some constraint
108 xbt_assert(cnst.get_concurrency_limit() < 0 || elem.variable->staged_sharing_penalty_ == 0 ||
109 elem.variable->get_min_concurrency_slack() == 0,
110 "should not have staged variable!");
113 xbt_assert(cnst.get_concurrency_limit() < 0 || cnst.get_concurrency_limit() >= concurrency,
114 "concurrency check failed!");
115 xbt_assert(cnst.concurrency_current_ == concurrency, "concurrency_current is out-of-date!");
118 // Check that for each variable, all corresponding elements are in the same state (i.e. same element sets)
119 for (Variable const& var : variable_set) {
120 if (var.cnsts_.empty())
123 const Element& elem = var.cnsts_[0];
124 bool belong_to_enabled = elem.enabled_element_set_hook.is_linked();
125 bool belong_to_disabled = elem.disabled_element_set_hook.is_linked();
126 bool belong_to_active = elem.active_element_set_hook.is_linked();
128 for (Element const& elem2 : var.cnsts_) {
129 xbt_assert(belong_to_enabled == elem2.enabled_element_set_hook.is_linked(),
130 "Variable inconsistency (1): enabled_element_set");
131 xbt_assert(belong_to_disabled == elem2.disabled_element_set_hook.is_linked(),
132 "Variable inconsistency (2): disabled_element_set");
133 xbt_assert(belong_to_active == elem2.active_element_set_hook.is_linked(),
134 "Variable inconsistency (3): active_element_set");
139 void System::var_free(Variable* var)
141 XBT_IN("(sys=%p, var=%p)", this, var);
144 // TODOLATER Can do better than that by leaving only the variable in only one enabled_element_set, call
145 // update_modified_set, and then remove it..
146 update_modified_cnst_set_from_variable(var);
148 for (Element& elem : var->cnsts_) {
149 if (var->sharing_penalty_ > 0)
150 elem.decrease_concurrency();
151 if (elem.enabled_element_set_hook.is_linked())
152 simgrid::xbt::intrusive_erase(elem.constraint->enabled_element_set_, elem);
153 if (elem.disabled_element_set_hook.is_linked())
154 simgrid::xbt::intrusive_erase(elem.constraint->disabled_element_set_, elem);
155 if (elem.active_element_set_hook.is_linked())
156 simgrid::xbt::intrusive_erase(elem.constraint->active_element_set_, elem);
157 if (elem.constraint->enabled_element_set_.empty() && elem.constraint->disabled_element_set_.empty())
158 make_constraint_inactive(elem.constraint);
160 on_disabled_var(elem.constraint);
167 xbt_mallocator_release(variable_mallocator_, var);
171 System::System(bool selective_update) : selective_update_active(selective_update)
173 XBT_DEBUG("Setting selective_update_active flag to %d", selective_update_active);
175 if (selective_update)
176 modified_set_ = std::make_unique<kernel::resource::Action::ModifiedSet>();
181 while (Variable* var = extract_variable()) {
182 const char* name = var->id_ ? typeid(*var->id_).name() : "(unidentified)";
183 boost::core::scoped_demangled_name demangled(name);
184 XBT_WARN("Probable bug: a %s variable (#%d) not removed before the LMM system destruction.",
185 demangled.get() ? demangled.get() : name, var->rank_);
188 while (Constraint* cnst = extract_constraint())
191 xbt_mallocator_free(variable_mallocator_);
194 void System::cnst_free(Constraint* cnst)
196 make_constraint_inactive(cnst);
200 Constraint::Constraint(resource::Resource* id_value, double bound_value) : bound_(bound_value), id_(id_value)
202 rank_ = next_rank_++;
205 Constraint* System::constraint_new(resource::Resource* id, double bound_value)
207 auto* cnst = new Constraint(id, bound_value);
208 insert_constraint(cnst);
212 void* System::variable_mallocator_new_f()
217 void System::variable_mallocator_free_f(void* var)
219 delete static_cast<Variable*>(var);
222 Variable* System::variable_new(resource::Action* id, double sharing_penalty, double bound, size_t number_of_constraints)
224 XBT_IN("(sys=%p, id=%p, penalty=%f, bound=%f, num_cons =%zu)", this, id, sharing_penalty, bound,
225 number_of_constraints);
227 auto* var = static_cast<Variable*>(xbt_mallocator_get(variable_mallocator_));
228 var->initialize(id, sharing_penalty, bound, number_of_constraints, visited_counter_ - 1);
229 if (sharing_penalty > 0)
230 variable_set.push_front(*var);
232 variable_set.push_back(*var);
234 XBT_OUT(" returns %p", var);
238 void System::variable_free(Variable* var)
240 remove_variable(var);
244 void System::variable_free_all()
246 while (Variable* var = extract_variable())
250 Element& System::expand_create_elem(Constraint* cnst, Variable* var, double consumption_weight)
252 xbt_assert(var->cnsts_.size() < var->cnsts_.capacity(), "Too much constraints");
254 var->cnsts_.emplace_back(cnst, var, consumption_weight);
255 Element& elem = var->cnsts_.back();
257 if (var->sharing_penalty_ != 0.0) {
258 elem.constraint->enabled_element_set_.push_front(elem);
260 elem.constraint->disabled_element_set_.push_back(elem);
262 if (elem.consumption_weight > 0 || var->sharing_penalty_ > 0) {
263 make_constraint_active(cnst);
268 Element& System::expand_add_to_elem(Element& elem, const Constraint* cnst, double consumption_weight) const
270 elem.max_consumption_weight = std::max(elem.max_consumption_weight, consumption_weight);
271 if (cnst->sharing_policy_ != Constraint::SharingPolicy::FATPIPE)
272 elem.consumption_weight += consumption_weight;
274 elem.consumption_weight = std::max(elem.consumption_weight, consumption_weight);
278 void System::expand(Constraint* cnst, Variable* var, double consumption_weight, bool force_creation)
283 std::find_if(begin(var->cnsts_), end(var->cnsts_), [&cnst](Element const& x) { return x.constraint == cnst; });
285 bool reuse_elem = elem_it != end(var->cnsts_) && not force_creation;
286 if (reuse_elem && var->sharing_penalty_ != 0.0) {
287 /* before changing it, decreases concurrency on constraint, it'll be added back later */
288 elem_it->decrease_concurrency();
290 Element& elem = reuse_elem ? expand_add_to_elem(*elem_it, cnst, consumption_weight)
291 : expand_create_elem(cnst, var, consumption_weight);
293 // Check if we need to disable the variable
294 if (var->sharing_penalty_ != 0) {
295 /* increase concurrency in constraint that this element uses.
296 * as we don't check if constraint has reached its limit before increasing,
297 * we can't check the correct state at increase_concurrency, anyway
298 * it'll check if the slack is smaller than 0 just below */
299 elem.increase_concurrency(false);
300 if (cnst->get_concurrency_slack() < 0) {
301 double penalty = var->sharing_penalty_;
303 for (Element const& elem2 : var->cnsts_)
304 on_disabled_var(elem2.constraint);
305 var->staged_sharing_penalty_ = penalty;
306 xbt_assert(not var->sharing_penalty_);
310 /* update modified constraint set accordingly */
311 if (elem.consumption_weight > 0 || var->sharing_penalty_ > 0)
312 update_modified_cnst_set(cnst);
317 Variable* Constraint::get_variable(const Element** elem) const
319 if (*elem == nullptr) {
320 // That is the first call, pick the first element among enabled_element_set (or disabled_element_set if
321 // enabled_element_set is empty)
322 if (not enabled_element_set_.empty())
323 *elem = &enabled_element_set_.front();
324 else if (not disabled_element_set_.empty())
325 *elem = &disabled_element_set_.front();
327 // elem is not null, so we carry on
328 if ((*elem)->enabled_element_set_hook.is_linked()) {
329 // Look at enabled_element_set, and jump to disabled_element_set when finished
330 auto iter = std::next(enabled_element_set_.iterator_to(**elem));
331 if (iter != std::end(enabled_element_set_))
333 else if (not disabled_element_set_.empty())
334 *elem = &disabled_element_set_.front();
338 auto iter = std::next(disabled_element_set_.iterator_to(**elem));
339 *elem = iter != std::end(disabled_element_set_) ? &*iter : nullptr;
343 return (*elem)->variable;
348 // if we modify the list between calls, normal version may loop forever
349 // this safe version ensures that we browse the list elements only once
350 Variable* Constraint::get_variable_safe(const Element** elem, const Element** nextelem, size_t* numelem) const
352 if (*elem == nullptr) {
353 *numelem = enabled_element_set_.size() + disabled_element_set_.size() - 1;
354 if (not enabled_element_set_.empty())
355 *elem = &enabled_element_set_.front();
356 else if (not disabled_element_set_.empty())
357 *elem = &disabled_element_set_.front();
366 // elem is not null, so we carry on
367 if ((*elem)->enabled_element_set_hook.is_linked()) {
368 // Look at enabled_element_set, and jump to disabled_element_set when finished
369 auto iter = std::next(enabled_element_set_.iterator_to(**elem));
370 if (iter != std::end(enabled_element_set_))
372 else if (not disabled_element_set_.empty())
373 *nextelem = &disabled_element_set_.front();
377 auto iter = std::next(disabled_element_set_.iterator_to(**elem));
378 *nextelem = iter != std::end(disabled_element_set_) ? &*iter : nullptr;
380 return (*elem)->variable;
385 template <class ElemList>
386 static void format_element_list(const ElemList& elem_list, Constraint::SharingPolicy sharing_policy, double& sum,
389 for (Element const& elem : elem_list) {
390 buf += std::to_string(elem.consumption_weight) + ".'" + std::to_string(elem.variable->rank_) + "'(" +
391 std::to_string(elem.variable->value_) + ")" +
392 (sharing_policy != Constraint::SharingPolicy::FATPIPE ? " + " : " , ");
393 if (sharing_policy != Constraint::SharingPolicy::FATPIPE)
394 sum += elem.consumption_weight * elem.variable->value_;
396 sum = std::max(sum, elem.consumption_weight * elem.variable->value_);
400 void System::print() const
402 std::string buf = "MAX-MIN ( ";
404 /* Printing Objective */
405 for (Variable const& var : variable_set)
406 buf += "'" + std::to_string(var.rank_) + "'(" + std::to_string(var.sharing_penalty_) + ") ";
408 XBT_DEBUG("%20s", buf.c_str());
411 XBT_DEBUG("Constraints");
412 /* Printing Constraints */
413 for (Constraint const& cnst : active_constraint_set) {
415 // Show the enabled variables
417 buf += cnst.sharing_policy_ != Constraint::SharingPolicy::FATPIPE ? "(" : "max(";
418 format_element_list(cnst.enabled_element_set_, cnst.sharing_policy_, sum, buf);
419 // TODO: Adding disabled elements only for test compatibility, but do we really want them to be printed?
420 format_element_list(cnst.disabled_element_set_, cnst.sharing_policy_, sum, buf);
422 buf += "0) <= " + std::to_string(cnst.bound_) + " ('" + std::to_string(cnst.rank_) + "')";
424 if (cnst.sharing_policy_ == Constraint::SharingPolicy::FATPIPE) {
425 buf += " [MAX-Constraint]";
427 XBT_DEBUG("%s", buf.c_str());
429 xbt_assert(not double_positive(sum - cnst.bound_, cnst.bound_ * sg_maxmin_precision),
430 "Incorrect value (%f is not smaller than %f): %g", sum, cnst.bound_, sum - cnst.bound_);
433 XBT_DEBUG("Variables");
434 /* Printing Result */
435 for (Variable const& var : variable_set) {
436 if (var.bound_ > 0) {
437 XBT_DEBUG("'%d'(%f) : %f (<=%f)", var.rank_, var.sharing_penalty_, var.value_, var.bound_);
438 xbt_assert(not double_positive(var.value_ - var.bound_, var.bound_ * sg_maxmin_precision),
439 "Incorrect value (%f is not smaller than %f", var.value_, var.bound_);
441 XBT_DEBUG("'%d'(%f) : %f", var.rank_, var.sharing_penalty_, var.value_);
446 resource::Action::ModifiedSet* System::get_modified_action_set() const
448 return modified_set_.get();
459 if (selective_update_active) {
460 /* update list of modified variables */
461 for (const Constraint& cnst : modified_constraint_set) {
462 for (const Element& elem : cnst.enabled_element_set_) {
463 if (elem.consumption_weight > 0) {
464 resource::Action* action = elem.variable->id_;
465 if (not action->is_within_modified_set())
466 modified_set_->push_back(*action);
470 /* clear list of modified constraint */
471 remove_all_modified_cnst_set();
474 if (XBT_LOG_ISENABLED(ker_lmm, xbt_log_priority_debug)) {
481 /** @brief Attribute the value bound to var->bound.
483 * @param var the Variable*
484 * @param bound the new bound to associate with var
486 * Makes var->bound equal to bound. Whenever this function is called a change is signed in the system. To
487 * avoid false system changing detection it is a good idea to test (bound != 0) before calling it.
489 void System::update_variable_bound(Variable* var, double bound)
494 if (not var->cnsts_.empty()) {
495 for (Element const& elem : var->cnsts_) {
496 update_modified_cnst_set(elem.constraint);
501 void Variable::initialize(resource::Action* id_value, double sharing_penalty, double bound_value,
502 size_t number_of_constraints, unsigned visited_value)
505 rank_ = next_rank_++;
506 cnsts_.reserve(number_of_constraints);
507 sharing_penalty_ = sharing_penalty;
508 staged_sharing_penalty_ = 0.0;
509 bound_ = bound_value;
511 visited_ = visited_value;
514 xbt_assert(not variable_set_hook_.is_linked());
515 xbt_assert(not saturated_variable_set_hook_.is_linked());
518 int Variable::get_min_concurrency_slack() const
520 int minslack = std::numeric_limits<int>::max();
521 for (Element const& elem : cnsts_) {
522 int slack = elem.constraint->get_concurrency_slack();
523 if (slack < minslack) {
524 // This is only an optimization, to avoid looking at more constraints when slack is already zero
533 // Small remark: In this implementation of System::enable_var() and System::disable_var(), we will meet multiple times
534 // with var when running System::update_modified_cnst_set().
535 // A priori not a big performance issue, but we might do better by calling System::update_modified_cnst_set() within the
536 // for loops (after doing the first for enabling==1, and before doing the last for disabling==1)
537 void System::enable_var(Variable* var)
539 xbt_assert(not XBT_LOG_ISENABLED(ker_lmm, xbt_log_priority_debug) || var->can_enable());
541 var->sharing_penalty_ = var->staged_sharing_penalty_;
542 var->staged_sharing_penalty_ = 0;
544 // Enabling the variable, move var to list head. Subtlety is: here, we need to call update_modified_cnst_set AFTER
545 // moving at least one element of var.
547 simgrid::xbt::intrusive_erase(variable_set, *var);
548 variable_set.push_front(*var);
549 for (Element& elem : var->cnsts_) {
550 simgrid::xbt::intrusive_erase(elem.constraint->disabled_element_set_, elem);
551 elem.constraint->enabled_element_set_.push_front(elem);
552 elem.increase_concurrency();
554 update_modified_cnst_set_from_variable(var);
556 // When used within on_disabled_var, we would get an assertion fail, because transiently there can be variables
557 // that are staged and could be activated.
558 // Anyway, caller functions all call check_concurrency() in the end.
561 void System::disable_var(Variable* var)
563 xbt_assert(not var->staged_sharing_penalty_, "Staged penalty should have been cleared");
564 // Disabling the variable, move to var to list tail. Subtlety is: here, we need to call update_modified_cnst_set
565 // BEFORE moving the last element of var.
566 simgrid::xbt::intrusive_erase(variable_set, *var);
567 variable_set.push_back(*var);
568 update_modified_cnst_set_from_variable(var);
569 for (Element& elem : var->cnsts_) {
570 simgrid::xbt::intrusive_erase(elem.constraint->enabled_element_set_, elem);
571 elem.constraint->disabled_element_set_.push_back(elem);
572 if (elem.active_element_set_hook.is_linked())
573 simgrid::xbt::intrusive_erase(elem.constraint->active_element_set_, elem);
574 elem.decrease_concurrency();
577 var->sharing_penalty_ = 0.0;
578 var->staged_sharing_penalty_ = 0.0;
583 /* /brief Find variables that can be enabled and enable them.
585 * Assuming that the variable has already been removed from non-zero penalties
586 * Can we find a staged variable to add?
587 * If yes, check that none of the constraints that this variable is involved in is at the limit of its concurrency
588 * And then add it to enabled variables
590 void System::on_disabled_var(Constraint* cnstr)
592 if (cnstr->get_concurrency_limit() < 0)
595 size_t numelem = cnstr->disabled_element_set_.size();
599 Element* elem = &cnstr->disabled_element_set_.front();
601 // Cannot use foreach loop, because System::enable_var() will modify disabled_element_set.. within the loop
602 while (numelem-- && elem) {
604 if (elem->disabled_element_set_hook.is_linked()) {
605 auto iter = std::next(cnstr->disabled_element_set_.iterator_to(*elem));
606 nextelem = iter != std::end(cnstr->disabled_element_set_) ? &*iter : nullptr;
611 if (elem->variable->staged_sharing_penalty_ > 0 && elem->variable->can_enable()) {
612 // Found a staged variable
613 // TODOLATER: Add random timing function to model reservation protocol fuzziness? Then how to make sure that
614 // staged variables will eventually be called?
615 enable_var(elem->variable);
618 xbt_assert(cnstr->concurrency_current_ <= cnstr->get_concurrency_limit(), "Concurrency overflow!");
619 if (cnstr->concurrency_current_ == cnstr->get_concurrency_limit())
625 // We could get an assertion fail, because transiently there can be variables that are staged and could be activated.
626 // And we need to go through all constraints of the disabled var before getting back a coherent state.
627 // Anyway, caller functions all call check_concurrency() in the end.
630 /** @brief update the penalty of a variable (disable it by passing 0 as a penalty) */
631 void System::update_variable_penalty(Variable* var, double penalty)
633 xbt_assert(penalty >= 0, "Variable penalty should not be negative!");
634 if (penalty == var->sharing_penalty_)
637 bool enabling_var = (penalty > 0 && var->sharing_penalty_ <= 0);
638 bool disabling_var = (penalty <= 0 && var->sharing_penalty_ > 0);
640 XBT_IN("(sys=%p, var=%p, var->sharing_penalty = %f, penalty=%f)", this, var, var->sharing_penalty_, penalty);
644 // Are we enabling this variable?
646 var->staged_sharing_penalty_ = penalty;
647 int minslack = var->get_min_concurrency_slack();
649 XBT_DEBUG("Staging var (instead of enabling) because min concurrency slack is 0");
652 XBT_DEBUG("Enabling var with min concurrency slack %i", minslack);
654 } else if (disabling_var) {
657 var->sharing_penalty_ = penalty;
658 update_modified_cnst_set_from_variable(var);
666 void System::update_constraint_bound(Constraint* cnst, double bound)
669 update_modified_cnst_set(cnst);
670 cnst->bound_ = bound;
673 /** @brief Update the constraint set propagating recursively to other constraints so the system should not be entirely
676 * @param cnst the Constraint* affected by the change
678 * A recursive algorithm to optimize the system recalculation selecting only constraints that have changed. Each
679 * constraint change is propagated to the list of constraints for each variable.
681 void System::update_modified_cnst_set_rec(const Constraint* cnst)
683 for (Element const& elem : cnst->enabled_element_set_) {
684 Variable* var = elem.variable;
685 for (Element const& elem2 : var->cnsts_) {
686 if (var->visited_ == visited_counter_)
688 if (elem2.constraint != cnst && not elem2.constraint->modified_constraint_set_hook_.is_linked()) {
689 modified_constraint_set.push_back(*elem2.constraint);
690 update_modified_cnst_set_rec(elem2.constraint);
693 // var will be ignored in later visits as long as sys->visited_counter does not move
694 var->visited_ = visited_counter_;
698 void System::update_modified_cnst_set_from_variable(const Variable* var)
700 /* nothing to update in these cases:
701 * - selective update not active, all variables are active
702 * - variable doesn't use any constraint
703 * - variable is disabled (sharing penalty <= 0): we iterate only through the enabled_variables in
704 * update_modified_cnst_set_rec */
705 if (not selective_update_active || var->cnsts_.empty() || var->sharing_penalty_ <= 0)
708 /* Normally, if the conditions above are true, specially variable is enabled, we can call
709 * modified_set over the first contraint only, since the recursion in update_modified_cnst_set_rec
710 * will iterate over the other constraints of this variable */
711 update_modified_cnst_set(var->cnsts_[0].constraint);
714 void System::update_modified_cnst_set(Constraint* cnst)
716 /* nothing to do if selective update isn't active */
717 if (selective_update_active && not cnst->modified_constraint_set_hook_.is_linked()) {
718 modified_constraint_set.push_back(*cnst);
719 update_modified_cnst_set_rec(cnst);
723 void System::remove_all_modified_cnst_set()
725 // We cleverly un-flag all variables just by incrementing visited_counter
726 // In effect, the var->visited value will no more be equal to visited counter
727 // To be clean, when visited counter has wrapped around, we force these var->visited values so that variables that
728 // were in the modified a long long time ago are not wrongly skipped here, which would lead to very nasty bugs
729 // (i.e. not readily reproducible, and requiring a lot of run time before happening).
730 if (++visited_counter_ == 1) {
731 /* the counter wrapped around, reset each variable->visited */
732 for (Variable& var : variable_set)
735 modified_constraint_set.clear();
739 * Returns resource load (in flop per second, or byte per second, or similar)
741 * If the resource is shared (the default case), the load is sum of resource usage made by
742 * every variables located on this resource.
744 * If the resource is not shared (ie in FATPIPE mode), then the load is the max (not the sum)
745 * of all resource usages located on this resource.
747 double Constraint::get_usage() const
750 if (sharing_policy_ != SharingPolicy::FATPIPE) {
751 for (Element const& elem : enabled_element_set_)
752 if (elem.consumption_weight > 0)
753 result += elem.consumption_weight * elem.variable->value_;
755 for (Element const& elem : enabled_element_set_)
756 if (elem.consumption_weight > 0)
757 result = std::max(result, elem.consumption_weight * elem.variable->value_);
762 void Constraint::set_sharing_policy(SharingPolicy policy, const s4u::NonLinearResourceCb& cb)
764 xbt_assert(policy == SharingPolicy::NONLINEAR || policy == SharingPolicy::WIFI || not cb,
765 "Invalid sharing policy for constraint. Callback should be used with NONLINEAR sharing policy");
766 sharing_policy_ = policy;
767 dyn_constraint_cb_ = cb;
770 } // namespace simgrid::kernel::lmm