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 */
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 // 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 behavior 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(bool check_limit)
50 constraint->concurrency_current_ += get_concurrency();
52 if (constraint->concurrency_current_ > constraint->concurrency_maximum_)
53 constraint->concurrency_maximum_ = constraint->concurrency_current_;
55 xbt_assert(not check_limit || constraint->get_concurrency_limit() < 0 ||
56 constraint->concurrency_current_ <= constraint->get_concurrency_limit(),
57 "Concurrency limit overflow!");
60 System* System::build(const std::string& solver_name, bool selective_update)
62 System* system = nullptr;
63 if (solver_name == "bmf") {
64 #if SIMGRID_HAVE_EIGEN3
65 system = new BmfSystem(selective_update);
67 } else if (solver_name == "fairbottleneck") {
68 system = new FairBottleneck(selective_update);
70 system = new MaxMin(selective_update);
75 void System::validate_solver(const std::string& solver_name)
77 static const std::vector<std::string> opts{"bmf", "maxmin", "fairbottleneck"};
78 if (solver_name == "bmf") {
79 #if !SIMGRID_HAVE_EIGEN3
80 xbt_die("Cannot use the BMF solver without installing Eigen3.");
83 if (std::find(opts.begin(), opts.end(), solver_name) == std::end(opts)) {
84 xbt_die("Invalid system solver, it should be one of: \"maxmin\", \"fairbottleneck\" or \"bmf\"");
88 void System::check_concurrency() const
90 // These checks are very expensive, so do them only if we want to debug SURF LMM
91 if (not XBT_LOG_ISENABLED(ker_lmm, xbt_log_priority_debug))
94 for (Constraint const& cnst : constraint_set) {
96 for (Element const& elem : cnst.enabled_element_set_) {
97 xbt_assert(elem.variable->sharing_penalty_ > 0);
98 concurrency += elem.get_concurrency();
101 for (Element const& elem : cnst.disabled_element_set_) {
102 // We should have staged variables only if concurrency is reached in some constraint
103 xbt_assert(cnst.get_concurrency_limit() < 0 || elem.variable->staged_sharing_penalty_ == 0 ||
104 elem.variable->get_min_concurrency_slack() == 0,
105 "should not have staged variable!");
108 xbt_assert(cnst.get_concurrency_limit() < 0 || cnst.get_concurrency_limit() >= concurrency,
109 "concurrency check failed!");
110 xbt_assert(cnst.concurrency_current_ == concurrency, "concurrency_current is out-of-date!");
113 // Check that for each variable, all corresponding elements are in the same state (i.e. same element sets)
114 for (Variable const& var : variable_set) {
115 if (var.cnsts_.empty())
118 const Element& elem = var.cnsts_[0];
119 bool belong_to_enabled = elem.enabled_element_set_hook.is_linked();
120 bool belong_to_disabled = elem.disabled_element_set_hook.is_linked();
121 bool belong_to_active = elem.active_element_set_hook.is_linked();
123 for (Element const& elem2 : var.cnsts_) {
124 xbt_assert(belong_to_enabled == elem2.enabled_element_set_hook.is_linked(),
125 "Variable inconsistency (1): enabled_element_set");
126 xbt_assert(belong_to_disabled == elem2.disabled_element_set_hook.is_linked(),
127 "Variable inconsistency (2): disabled_element_set");
128 xbt_assert(belong_to_active == elem2.active_element_set_hook.is_linked(),
129 "Variable inconsistency (3): active_element_set");
134 void System::var_free(Variable* var)
136 XBT_IN("(sys=%p, var=%p)", this, var);
139 // TODOLATER Can do better than that by leaving only the variable in only one enabled_element_set, call
140 // update_modified_set, and then remove it..
141 update_modified_cnst_set_from_variable(var);
143 for (Element& elem : var->cnsts_) {
144 if (var->sharing_penalty_ > 0)
145 elem.decrease_concurrency();
146 if (elem.enabled_element_set_hook.is_linked())
147 simgrid::xbt::intrusive_erase(elem.constraint->enabled_element_set_, elem);
148 if (elem.disabled_element_set_hook.is_linked())
149 simgrid::xbt::intrusive_erase(elem.constraint->disabled_element_set_, elem);
150 if (elem.active_element_set_hook.is_linked())
151 simgrid::xbt::intrusive_erase(elem.constraint->active_element_set_, elem);
152 if (elem.constraint->enabled_element_set_.empty() && elem.constraint->disabled_element_set_.empty())
153 make_constraint_inactive(elem.constraint);
155 on_disabled_var(elem.constraint);
162 xbt_mallocator_release(variable_mallocator_, var);
166 System::System(bool selective_update) : selective_update_active(selective_update)
168 XBT_DEBUG("Setting selective_update_active flag to %d", selective_update_active);
170 if (selective_update)
171 modified_set_ = std::make_unique<kernel::resource::Action::ModifiedSet>();
176 while (Variable* var = extract_variable()) {
177 const char* name = var->id_ ? typeid(*var->id_).name() : "(unidentified)";
178 boost::core::scoped_demangled_name demangled(name);
179 XBT_WARN("Probable bug: a %s variable (#%d) not removed before the LMM system destruction.",
180 demangled.get() ? demangled.get() : name, var->rank_);
183 while (Constraint* cnst = extract_constraint())
186 xbt_mallocator_free(variable_mallocator_);
189 void System::cnst_free(Constraint* cnst)
191 make_constraint_inactive(cnst);
195 Constraint::Constraint(resource::Resource* id_value, double bound_value) : bound_(bound_value), id_(id_value)
197 rank_ = next_rank_++;
200 Constraint* System::constraint_new(resource::Resource* id, double bound_value)
202 auto* cnst = new Constraint(id, bound_value);
203 insert_constraint(cnst);
207 void* System::variable_mallocator_new_f()
212 void System::variable_mallocator_free_f(void* var)
214 delete static_cast<Variable*>(var);
217 Variable* System::variable_new(resource::Action* id, double sharing_penalty, double bound, size_t number_of_constraints)
219 XBT_IN("(sys=%p, id=%p, penalty=%f, bound=%f, num_cons =%zu)", this, id, sharing_penalty, bound,
220 number_of_constraints);
222 auto* var = static_cast<Variable*>(xbt_mallocator_get(variable_mallocator_));
223 var->initialize(id, sharing_penalty, bound, number_of_constraints, visited_counter_ - 1);
224 if (sharing_penalty > 0)
225 variable_set.push_front(*var);
227 variable_set.push_back(*var);
229 XBT_OUT(" returns %p", var);
233 void System::variable_free(Variable* var)
235 remove_variable(var);
239 void System::variable_free_all()
241 while (Variable* var = extract_variable())
245 Element& System::expand_create_elem(Constraint* cnst, Variable* var, double consumption_weight)
247 xbt_assert(var->cnsts_.size() < var->cnsts_.capacity(), "Too much constraints");
249 var->cnsts_.emplace_back(cnst, var, consumption_weight);
250 Element& elem = var->cnsts_.back();
252 if (var->sharing_penalty_ != 0.0) {
253 elem.constraint->enabled_element_set_.push_front(elem);
255 elem.constraint->disabled_element_set_.push_back(elem);
257 if (elem.consumption_weight > 0 || var->sharing_penalty_ > 0) {
258 make_constraint_active(cnst);
263 Element& System::expand_add_to_elem(Element& elem, const Constraint* cnst, double consumption_weight) const
265 elem.max_consumption_weight = std::max(elem.max_consumption_weight, consumption_weight);
266 if (cnst->sharing_policy_ != Constraint::SharingPolicy::FATPIPE)
267 elem.consumption_weight += consumption_weight;
269 elem.consumption_weight = std::max(elem.consumption_weight, consumption_weight);
273 void System::expand(Constraint* cnst, Variable* var, double consumption_weight)
278 std::find_if(begin(var->cnsts_), end(var->cnsts_), [&cnst](Element const& x) { return x.constraint == cnst; });
279 if (elem_it != end(var->cnsts_) && var->sharing_penalty_ != 0.0) {
280 /* before changing it, decreases concurrency on constraint, it'll be added back later */
281 elem_it->decrease_concurrency();
283 Element& elem = elem_it != end(var->cnsts_) ? expand_add_to_elem(*elem_it, cnst, consumption_weight)
284 : expand_create_elem(cnst, var, consumption_weight);
286 // Check if we need to disable the variable
287 if (var->sharing_penalty_ != 0) {
288 /* increase concurrency in constraint that this element uses.
289 * as we don't check if constraint has reached its limit before increasing,
290 * we can't check the correct state at increase_concurrency, anyway
291 * it'll check if the slack is smaller than 0 just below */
292 elem.increase_concurrency(false);
293 if (cnst->get_concurrency_slack() < 0) {
294 double penalty = var->sharing_penalty_;
296 for (Element const& elem2 : var->cnsts_)
297 on_disabled_var(elem2.constraint);
298 var->staged_sharing_penalty_ = penalty;
299 xbt_assert(not var->sharing_penalty_);
303 /* update modified constraint set accordingly */
304 if (elem.consumption_weight > 0 || var->sharing_penalty_ > 0)
305 update_modified_cnst_set(cnst);
310 Variable* Constraint::get_variable(const Element** elem) const
312 if (*elem == nullptr) {
313 // That is the first call, pick the first element among enabled_element_set (or disabled_element_set if
314 // enabled_element_set is empty)
315 if (not enabled_element_set_.empty())
316 *elem = &enabled_element_set_.front();
317 else if (not disabled_element_set_.empty())
318 *elem = &disabled_element_set_.front();
320 // elem is not null, so we carry on
321 if ((*elem)->enabled_element_set_hook.is_linked()) {
322 // Look at enabled_element_set, and jump to disabled_element_set when finished
323 auto iter = std::next(enabled_element_set_.iterator_to(**elem));
324 if (iter != std::end(enabled_element_set_))
326 else if (not disabled_element_set_.empty())
327 *elem = &disabled_element_set_.front();
331 auto iter = std::next(disabled_element_set_.iterator_to(**elem));
332 *elem = iter != std::end(disabled_element_set_) ? &*iter : nullptr;
336 return (*elem)->variable;
341 // if we modify the list between calls, normal version may loop forever
342 // this safe version ensures that we browse the list elements only once
343 Variable* Constraint::get_variable_safe(const Element** elem, const Element** nextelem, size_t* numelem) const
345 if (*elem == nullptr) {
346 *numelem = enabled_element_set_.size() + disabled_element_set_.size() - 1;
347 if (not enabled_element_set_.empty())
348 *elem = &enabled_element_set_.front();
349 else if (not disabled_element_set_.empty())
350 *elem = &disabled_element_set_.front();
359 // elem is not null, so we carry on
360 if ((*elem)->enabled_element_set_hook.is_linked()) {
361 // Look at enabled_element_set, and jump to disabled_element_set when finished
362 auto iter = std::next(enabled_element_set_.iterator_to(**elem));
363 if (iter != std::end(enabled_element_set_))
365 else if (not disabled_element_set_.empty())
366 *nextelem = &disabled_element_set_.front();
370 auto iter = std::next(disabled_element_set_.iterator_to(**elem));
371 *nextelem = iter != std::end(disabled_element_set_) ? &*iter : nullptr;
373 return (*elem)->variable;
378 template <class ElemList>
379 static void format_element_list(const ElemList& elem_list, Constraint::SharingPolicy sharing_policy, double& sum,
382 for (Element const& elem : elem_list) {
383 buf += std::to_string(elem.consumption_weight) + ".'" + std::to_string(elem.variable->rank_) + "'(" +
384 std::to_string(elem.variable->value_) + ")" +
385 (sharing_policy != Constraint::SharingPolicy::FATPIPE ? " + " : " , ");
386 if (sharing_policy != Constraint::SharingPolicy::FATPIPE)
387 sum += elem.consumption_weight * elem.variable->value_;
389 sum = std::max(sum, elem.consumption_weight * elem.variable->value_);
393 void System::print() const
395 std::string buf = "MAX-MIN ( ";
397 /* Printing Objective */
398 for (Variable const& var : variable_set)
399 buf += "'" + std::to_string(var.rank_) + "'(" + std::to_string(var.sharing_penalty_) + ") ";
401 XBT_DEBUG("%20s", buf.c_str());
404 XBT_DEBUG("Constraints");
405 /* Printing Constraints */
406 for (Constraint const& cnst : active_constraint_set) {
408 // Show the enabled variables
410 buf += cnst.sharing_policy_ != Constraint::SharingPolicy::FATPIPE ? "(" : "max(";
411 format_element_list(cnst.enabled_element_set_, cnst.sharing_policy_, sum, buf);
412 // TODO: Adding disabled elements only for test compatibility, but do we really want them to be printed?
413 format_element_list(cnst.disabled_element_set_, cnst.sharing_policy_, sum, buf);
415 buf += "0) <= " + std::to_string(cnst.bound_) + " ('" + std::to_string(cnst.rank_) + "')";
417 if (cnst.sharing_policy_ == Constraint::SharingPolicy::FATPIPE) {
418 buf += " [MAX-Constraint]";
420 XBT_DEBUG("%s", buf.c_str());
422 xbt_assert(not double_positive(sum - cnst.bound_, cnst.bound_ * sg_maxmin_precision),
423 "Incorrect value (%f is not smaller than %f): %g", sum, cnst.bound_, sum - cnst.bound_);
426 XBT_DEBUG("Variables");
427 /* Printing Result */
428 for (Variable const& var : variable_set) {
429 if (var.bound_ > 0) {
430 XBT_DEBUG("'%d'(%f) : %f (<=%f)", var.rank_, var.sharing_penalty_, var.value_, var.bound_);
431 xbt_assert(not double_positive(var.value_ - var.bound_, var.bound_ * sg_maxmin_precision),
432 "Incorrect value (%f is not smaller than %f", var.value_, var.bound_);
434 XBT_DEBUG("'%d'(%f) : %f", var.rank_, var.sharing_penalty_, var.value_);
439 resource::Action::ModifiedSet* System::get_modified_action_set() const
441 return modified_set_.get();
452 if (selective_update_active) {
453 /* update list of modified variables */
454 for (const Constraint& cnst : modified_constraint_set) {
455 for (const Element& elem : cnst.enabled_element_set_) {
456 if (elem.consumption_weight > 0) {
457 resource::Action* action = elem.variable->id_;
458 if (not action->is_within_modified_set())
459 modified_set_->push_back(*action);
463 /* clear list of modified constraint */
464 remove_all_modified_cnst_set();
467 if (XBT_LOG_ISENABLED(ker_lmm, xbt_log_priority_debug)) {
474 /** @brief Attribute the value bound to var->bound.
476 * @param var the Variable*
477 * @param bound the new bound to associate with var
479 * Makes var->bound equal to bound. Whenever this function is called a change is signed in the system. To
480 * avoid false system changing detection it is a good idea to test (bound != 0) before calling it.
482 void System::update_variable_bound(Variable* var, double bound)
487 if (not var->cnsts_.empty()) {
488 for (Element const& elem : var->cnsts_) {
489 update_modified_cnst_set(elem.constraint);
494 void Variable::initialize(resource::Action* id_value, double sharing_penalty, double bound_value,
495 size_t number_of_constraints, unsigned visited_value)
498 rank_ = next_rank_++;
499 cnsts_.reserve(number_of_constraints);
500 sharing_penalty_ = sharing_penalty;
501 staged_sharing_penalty_ = 0.0;
502 bound_ = bound_value;
504 visited_ = visited_value;
507 xbt_assert(not variable_set_hook_.is_linked());
508 xbt_assert(not saturated_variable_set_hook_.is_linked());
511 int Variable::get_min_concurrency_slack() const
513 int minslack = std::numeric_limits<int>::max();
514 for (Element const& elem : cnsts_) {
515 int slack = elem.constraint->get_concurrency_slack();
516 if (slack < minslack) {
517 // This is only an optimization, to avoid looking at more constraints when slack is already zero
526 // Small remark: In this implementation of System::enable_var() and System::disable_var(), we will meet multiple times
527 // with var when running System::update_modified_cnst_set().
528 // A priori not a big performance issue, but we might do better by calling System::update_modified_cnst_set() within the
529 // for loops (after doing the first for enabling==1, and before doing the last for disabling==1)
530 void System::enable_var(Variable* var)
532 xbt_assert(not XBT_LOG_ISENABLED(ker_lmm, xbt_log_priority_debug) || var->can_enable());
534 var->sharing_penalty_ = var->staged_sharing_penalty_;
535 var->staged_sharing_penalty_ = 0;
537 // Enabling the variable, move var to list head. Subtlety is: here, we need to call update_modified_cnst_set AFTER
538 // moving at least one element of var.
540 simgrid::xbt::intrusive_erase(variable_set, *var);
541 variable_set.push_front(*var);
542 for (Element& elem : var->cnsts_) {
543 simgrid::xbt::intrusive_erase(elem.constraint->disabled_element_set_, elem);
544 elem.constraint->enabled_element_set_.push_front(elem);
545 elem.increase_concurrency();
547 update_modified_cnst_set_from_variable(var);
549 // When used within on_disabled_var, we would get an assertion fail, because transiently there can be variables
550 // that are staged and could be activated.
551 // Anyway, caller functions all call check_concurrency() in the end.
554 void System::disable_var(Variable* var)
556 xbt_assert(not var->staged_sharing_penalty_, "Staged penalty should have been cleared");
557 // Disabling the variable, move to var to list tail. Subtlety is: here, we need to call update_modified_cnst_set
558 // BEFORE moving the last element of var.
559 simgrid::xbt::intrusive_erase(variable_set, *var);
560 variable_set.push_back(*var);
561 update_modified_cnst_set_from_variable(var);
562 for (Element& elem : var->cnsts_) {
563 simgrid::xbt::intrusive_erase(elem.constraint->enabled_element_set_, elem);
564 elem.constraint->disabled_element_set_.push_back(elem);
565 if (elem.active_element_set_hook.is_linked())
566 simgrid::xbt::intrusive_erase(elem.constraint->active_element_set_, elem);
567 elem.decrease_concurrency();
570 var->sharing_penalty_ = 0.0;
571 var->staged_sharing_penalty_ = 0.0;
576 /* /brief Find variables that can be enabled and enable them.
578 * Assuming that the variable has already been removed from non-zero penalties
579 * Can we find a staged variable to add?
580 * If yes, check that none of the constraints that this variable is involved in is at the limit of its concurrency
581 * And then add it to enabled variables
583 void System::on_disabled_var(Constraint* cnstr)
585 if (cnstr->get_concurrency_limit() < 0)
588 size_t numelem = cnstr->disabled_element_set_.size();
592 Element* elem = &cnstr->disabled_element_set_.front();
594 // Cannot use foreach loop, because System::enable_var() will modify disabled_element_set.. within the loop
595 while (numelem-- && elem) {
597 if (elem->disabled_element_set_hook.is_linked()) {
598 auto iter = std::next(cnstr->disabled_element_set_.iterator_to(*elem));
599 nextelem = iter != std::end(cnstr->disabled_element_set_) ? &*iter : nullptr;
604 if (elem->variable->staged_sharing_penalty_ > 0 && elem->variable->can_enable()) {
605 // Found a staged variable
606 // TODOLATER: Add random timing function to model reservation protocol fuzziness? Then how to make sure that
607 // staged variables will eventually be called?
608 enable_var(elem->variable);
611 xbt_assert(cnstr->concurrency_current_ <= cnstr->get_concurrency_limit(), "Concurrency overflow!");
612 if (cnstr->concurrency_current_ == cnstr->get_concurrency_limit())
618 // We could get an assertion fail, because transiently there can be variables that are staged and could be activated.
619 // And we need to go through all constraints of the disabled var before getting back a coherent state.
620 // Anyway, caller functions all call check_concurrency() in the end.
623 /** @brief update the penalty of a variable (disable it by passing 0 as a penalty) */
624 void System::update_variable_penalty(Variable* var, double penalty)
626 xbt_assert(penalty >= 0, "Variable penalty should not be negative!");
627 if (penalty == var->sharing_penalty_)
630 bool enabling_var = (penalty > 0 && var->sharing_penalty_ <= 0);
631 bool disabling_var = (penalty <= 0 && var->sharing_penalty_ > 0);
633 XBT_IN("(sys=%p, var=%p, var->sharing_penalty = %f, penalty=%f)", this, var, var->sharing_penalty_, penalty);
637 // Are we enabling this variable?
639 var->staged_sharing_penalty_ = penalty;
640 int minslack = var->get_min_concurrency_slack();
642 XBT_DEBUG("Staging var (instead of enabling) because min concurrency slack is 0");
645 XBT_DEBUG("Enabling var with min concurrency slack %i", minslack);
647 } else if (disabling_var) {
650 var->sharing_penalty_ = penalty;
651 update_modified_cnst_set_from_variable(var);
659 void System::update_constraint_bound(Constraint* cnst, double bound)
662 update_modified_cnst_set(cnst);
663 cnst->bound_ = bound;
666 /** @brief Update the constraint set propagating recursively to other constraints so the system should not be entirely
669 * @param cnst the Constraint* affected by the change
671 * A recursive algorithm to optimize the system recalculation selecting only constraints that have changed. Each
672 * constraint change is propagated to the list of constraints for each variable.
674 void System::update_modified_cnst_set_rec(const Constraint* cnst)
676 for (Element const& elem : cnst->enabled_element_set_) {
677 Variable* var = elem.variable;
678 for (Element const& elem2 : var->cnsts_) {
679 if (var->visited_ == visited_counter_)
681 if (elem2.constraint != cnst && not elem2.constraint->modified_constraint_set_hook_.is_linked()) {
682 modified_constraint_set.push_back(*elem2.constraint);
683 update_modified_cnst_set_rec(elem2.constraint);
686 // var will be ignored in later visits as long as sys->visited_counter does not move
687 var->visited_ = visited_counter_;
691 void System::update_modified_cnst_set_from_variable(const Variable* var)
693 /* nothing to update in these cases:
694 * - selective update not active, all variables are active
695 * - variable doesn't use any constraint
696 * - variable is disabled (sharing penalty <= 0): we iterate only through the enabled_variables in
697 * update_modified_cnst_set_rec */
698 if (not selective_update_active || var->cnsts_.empty() || var->sharing_penalty_ <= 0)
701 /* Normally, if the conditions above are true, specially variable is enabled, we can call
702 * modified_set over the first contraint only, since the recursion in update_modified_cnst_set_rec
703 * will iterate over the other constraints of this variable */
704 update_modified_cnst_set(var->cnsts_[0].constraint);
707 void System::update_modified_cnst_set(Constraint* cnst)
709 /* nothing to do if selective update isn't active */
710 if (selective_update_active && not cnst->modified_constraint_set_hook_.is_linked()) {
711 modified_constraint_set.push_back(*cnst);
712 update_modified_cnst_set_rec(cnst);
716 void System::remove_all_modified_cnst_set()
718 // We cleverly un-flag all variables just by incrementing visited_counter
719 // In effect, the var->visited value will no more be equal to visited counter
720 // To be clean, when visited counter has wrapped around, we force these var->visited values so that variables that
721 // were in the modified a long long time ago are not wrongly skipped here, which would lead to very nasty bugs
722 // (i.e. not readily reproducible, and requiring a lot of run time before happening).
723 if (++visited_counter_ == 1) {
724 /* the counter wrapped around, reset each variable->visited */
725 for (Variable& var : variable_set)
728 modified_constraint_set.clear();
732 * Returns resource load (in flop per second, or byte per second, or similar)
734 * If the resource is shared (the default case), the load is sum of resource usage made by
735 * every variables located on this resource.
737 * If the resource is not shared (ie in FATPIPE mode), then the load is the max (not the sum)
738 * of all resource usages located on this resource.
740 double Constraint::get_usage() const
743 if (sharing_policy_ != SharingPolicy::FATPIPE) {
744 for (Element const& elem : enabled_element_set_)
745 if (elem.consumption_weight > 0)
746 result += elem.consumption_weight * elem.variable->value_;
748 for (Element const& elem : enabled_element_set_)
749 if (elem.consumption_weight > 0)
750 result = std::max(result, elem.consumption_weight * elem.variable->value_);
755 void Constraint::set_sharing_policy(SharingPolicy policy, const s4u::NonLinearResourceCb& cb)
757 xbt_assert(policy == SharingPolicy::NONLINEAR || not cb,
758 "Invalid sharing policy for constraint. Callback should be used with NONLINEAR sharing policy");
759 sharing_policy_ = policy;
760 dyn_constraint_cb_ = cb;
763 } // namespace simgrid::kernel::lmm