1 /* Copyright (c) 2004-2021. 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 <boost/core/demangle.hpp>
9 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(surf_maxmin, surf, "Logging specific to SURF (maxmin)");
11 double sg_maxmin_precision = 1E-5; /* Change this with --cfg=maxmin/precision:VALUE */
12 double sg_surf_precision = 1E-9; /* Change this with --cfg=surf/precision:VALUE */
13 int sg_concurrency_limit = -1; /* Change this with --cfg=maxmin/concurrency-limit:VALUE */
19 using dyn_light_t = std::vector<int>;
21 int Variable::next_rank_ = 1;
22 int Constraint::next_rank_ = 1;
24 int Element::get_concurrency() const
26 // Ignore element with weight less than one (e.g. cross-traffic)
27 return (consumption_weight >= 1) ? 1 : 0;
28 // There are other alternatives, but they will change the behavior of the model..
29 // So do not use it unless you want to make a new model.
30 // If you do, remember to change the variables concurrency share to reflect it.
31 // Potential examples are:
32 // return (elem->weight>0)?1:0;//Include element as soon as weight is non-zero
33 // return (int)ceil(elem->weight);//Include element as the rounded-up integer value of the element weight
36 void Element::decrease_concurrency()
38 xbt_assert(constraint->concurrency_current_ >= get_concurrency());
39 constraint->concurrency_current_ -= get_concurrency();
42 void Element::increase_concurrency()
44 constraint->concurrency_current_ += get_concurrency();
46 if (constraint->concurrency_current_ > constraint->concurrency_maximum_)
47 constraint->concurrency_maximum_ = constraint->concurrency_current_;
49 xbt_assert(constraint->get_concurrency_limit() < 0 ||
50 constraint->concurrency_current_ <= constraint->get_concurrency_limit(),
51 "Concurrency limit overflow!");
54 void System::check_concurrency() const
56 // These checks are very expensive, so do them only if we want to debug SURF LMM
57 if (not XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug))
60 for (Constraint const& cnst : constraint_set) {
62 for (Element const& elem : cnst.enabled_element_set_) {
63 xbt_assert(elem.variable->sharing_penalty_ > 0);
64 concurrency += elem.get_concurrency();
67 for (Element const& elem : cnst.disabled_element_set_) {
68 // We should have staged variables only if concurrency is reached in some constraint
69 xbt_assert(cnst.get_concurrency_limit() < 0 || elem.variable->staged_penalty_ == 0 ||
70 elem.variable->get_min_concurrency_slack() < elem.variable->concurrency_share_,
71 "should not have staged variable!");
74 xbt_assert(cnst.get_concurrency_limit() < 0 || cnst.get_concurrency_limit() >= concurrency,
75 "concurrency check failed!");
76 xbt_assert(cnst.concurrency_current_ == concurrency, "concurrency_current is out-of-date!");
79 // Check that for each variable, all corresponding elements are in the same state (i.e. same element sets)
80 for (Variable const& var : variable_set) {
81 if (var.cnsts_.empty())
84 const Element& elem = var.cnsts_[0];
85 bool belong_to_enabled = elem.enabled_element_set_hook.is_linked();
86 bool belong_to_disabled = elem.disabled_element_set_hook.is_linked();
87 bool belong_to_active = elem.active_element_set_hook.is_linked();
89 for (Element const& elem2 : var.cnsts_) {
90 xbt_assert(belong_to_enabled == elem2.enabled_element_set_hook.is_linked(),
91 "Variable inconsistency (1): enabled_element_set");
92 xbt_assert(belong_to_disabled == elem2.disabled_element_set_hook.is_linked(),
93 "Variable inconsistency (2): disabled_element_set");
94 xbt_assert(belong_to_active == elem2.active_element_set_hook.is_linked(),
95 "Variable inconsistency (3): active_element_set");
100 void System::var_free(Variable* var)
102 XBT_IN("(sys=%p, var=%p)", this, var);
105 // TODOLATER Can do better than that by leaving only the variable in only one enabled_element_set, call
106 // update_modified_set, and then remove it..
107 if (not var->cnsts_.empty())
108 update_modified_set(var->cnsts_[0].constraint);
110 for (Element& elem : var->cnsts_) {
111 if (var->sharing_penalty_ > 0)
112 elem.decrease_concurrency();
113 if (elem.enabled_element_set_hook.is_linked())
114 simgrid::xbt::intrusive_erase(elem.constraint->enabled_element_set_, elem);
115 if (elem.disabled_element_set_hook.is_linked())
116 simgrid::xbt::intrusive_erase(elem.constraint->disabled_element_set_, elem);
117 if (elem.active_element_set_hook.is_linked())
118 simgrid::xbt::intrusive_erase(elem.constraint->active_element_set_, elem);
119 int nelements = elem.constraint->enabled_element_set_.size() + elem.constraint->disabled_element_set_.size();
121 make_constraint_inactive(elem.constraint);
123 on_disabled_var(elem.constraint);
130 xbt_mallocator_release(variable_mallocator_, var);
134 System::System(bool selective_update) : selective_update_active(selective_update)
136 XBT_DEBUG("Setting selective_update_active flag to %d", selective_update_active);
138 if (selective_update)
139 modified_set_ = std::make_unique<kernel::resource::Action::ModifiedSet>();
144 while (Variable* var = extract_variable()) {
145 std::string demangled = boost::core::demangle(var->id_ ? typeid(*var->id_).name() : "(unidentified)");
146 XBT_WARN("Probable bug: a %s variable (#%d) not removed before the LMM system destruction.", demangled.c_str(),
150 while (Constraint* cnst = extract_constraint())
153 xbt_mallocator_free(variable_mallocator_);
156 void System::cnst_free(Constraint* cnst)
158 make_constraint_inactive(cnst);
162 Constraint::Constraint(resource::Resource* id_value, double bound_value) : bound_(bound_value), id_(id_value)
164 rank_ = next_rank_++;
167 Constraint* System::constraint_new(resource::Resource* id, double bound_value)
169 auto* cnst = new Constraint(id, bound_value);
170 insert_constraint(cnst);
174 void* System::variable_mallocator_new_f()
179 void System::variable_mallocator_free_f(void* var)
181 delete static_cast<Variable*>(var);
184 Variable* System::variable_new(resource::Action* id, double sharing_penalty, double bound, size_t number_of_constraints)
186 XBT_IN("(sys=%p, id=%p, penalty=%f, bound=%f, num_cons =%zu)", this, id, sharing_penalty, bound,
187 number_of_constraints);
189 auto* var = static_cast<Variable*>(xbt_mallocator_get(variable_mallocator_));
190 var->initialize(id, sharing_penalty, bound, number_of_constraints, visited_counter_ - 1);
191 if (sharing_penalty > 0)
192 variable_set.push_front(*var);
194 variable_set.push_back(*var);
196 XBT_OUT(" returns %p", var);
200 void System::variable_free(Variable* var)
202 remove_variable(var);
206 void System::variable_free_all()
208 while (Variable* var = extract_variable())
212 void System::expand(Constraint* cnst, Variable* var, double consumption_weight)
216 // Check if this variable already has an active element in this constraint
217 // If it does, subtract it from the required slack
218 int current_share = 0;
219 if (var->concurrency_share_ > 1) {
220 for (const Element& elem : var->cnsts_) {
221 if (elem.constraint == cnst && elem.enabled_element_set_hook.is_linked())
222 current_share += elem.get_concurrency();
226 // Check if we need to disable the variable
227 if (var->sharing_penalty_ > 0 && var->concurrency_share_ - current_share > cnst->get_concurrency_slack()) {
228 double penalty = var->sharing_penalty_;
230 for (Element const& elem : var->cnsts_)
231 on_disabled_var(elem.constraint);
232 consumption_weight = 0;
233 var->staged_penalty_ = penalty;
234 xbt_assert(not var->sharing_penalty_);
237 xbt_assert(var->cnsts_.size() < var->cnsts_.capacity(), "Too much constraints");
239 var->cnsts_.resize(var->cnsts_.size() + 1);
240 Element& elem = var->cnsts_.back();
242 elem.consumption_weight = consumption_weight;
243 elem.constraint = cnst;
246 if (var->sharing_penalty_ != 0.0) {
247 elem.constraint->enabled_element_set_.push_front(elem);
248 elem.increase_concurrency();
250 elem.constraint->disabled_element_set_.push_back(elem);
252 if (not selective_update_active) {
253 make_constraint_active(cnst);
254 } else if (elem.consumption_weight > 0 || var->sharing_penalty_ > 0) {
255 make_constraint_active(cnst);
256 update_modified_set(cnst);
257 // TODOLATER: Why do we need this second call?
258 if (var->cnsts_.size() > 1)
259 update_modified_set(var->cnsts_[0].constraint);
265 void System::expand_add(Constraint* cnst, Variable* var, double value)
271 // BEWARE: In case you have multiple elements in one constraint, this will always add value to the first element.
273 std::find_if(begin(var->cnsts_), end(var->cnsts_), [&cnst](Element const& x) { return x.constraint == cnst; });
274 if (elem_it != end(var->cnsts_)) {
275 Element& elem = *elem_it;
276 if (var->sharing_penalty_ != 0.0)
277 elem.decrease_concurrency();
279 if (cnst->sharing_policy_ != s4u::Link::SharingPolicy::FATPIPE)
280 elem.consumption_weight += value;
282 elem.consumption_weight = std::max(elem.consumption_weight, value);
284 // We need to check that increasing value of the element does not cross the concurrency limit
285 if (var->sharing_penalty_ != 0.0) {
286 if (cnst->get_concurrency_slack() < elem.get_concurrency()) {
287 double penalty = var->sharing_penalty_;
289 for (Element const& elem2 : var->cnsts_)
290 on_disabled_var(elem2.constraint);
291 var->staged_penalty_ = penalty;
292 xbt_assert(not var->sharing_penalty_);
294 elem.increase_concurrency();
296 update_modified_set(cnst);
298 expand(cnst, var, value);
303 Variable* Constraint::get_variable(const Element** elem) const
305 if (*elem == nullptr) {
306 // That is the first call, pick the first element among enabled_element_set (or disabled_element_set if
307 // enabled_element_set is empty)
308 if (not enabled_element_set_.empty())
309 *elem = &enabled_element_set_.front();
310 else if (not disabled_element_set_.empty())
311 *elem = &disabled_element_set_.front();
315 // elem is not null, so we carry on
316 if ((*elem)->enabled_element_set_hook.is_linked()) {
317 // Look at enabled_element_set, and jump to disabled_element_set when finished
318 auto iter = std::next(enabled_element_set_.iterator_to(**elem));
319 if (iter != std::end(enabled_element_set_))
321 else if (not disabled_element_set_.empty())
322 *elem = &disabled_element_set_.front();
326 auto iter = std::next(disabled_element_set_.iterator_to(**elem));
327 *elem = iter != std::end(disabled_element_set_) ? &*iter : nullptr;
331 return (*elem)->variable;
336 // if we modify the list between calls, normal version may loop forever
337 // this safe version ensures that we browse the list elements only once
338 Variable* Constraint::get_variable_safe(const Element** elem, const Element** nextelem, int* numelem) const
340 if (*elem == nullptr) {
341 *numelem = enabled_element_set_.size() + disabled_element_set_.size() - 1;
342 if (not enabled_element_set_.empty())
343 *elem = &enabled_element_set_.front();
344 else if (not disabled_element_set_.empty())
345 *elem = &disabled_element_set_.front();
356 // elem is not null, so we carry on
357 if ((*elem)->enabled_element_set_hook.is_linked()) {
358 // Look at enabled_element_set, and jump to disabled_element_set when finished
359 auto iter = std::next(enabled_element_set_.iterator_to(**elem));
360 if (iter != std::end(enabled_element_set_))
362 else if (not disabled_element_set_.empty())
363 *nextelem = &disabled_element_set_.front();
367 auto iter = std::next(disabled_element_set_.iterator_to(**elem));
368 *nextelem = iter != std::end(disabled_element_set_) ? &*iter : nullptr;
370 return (*elem)->variable;
375 static inline void saturated_constraints_update(double usage, int cnst_light_num, dyn_light_t& saturated_constraints,
378 xbt_assert(usage > 0, "Impossible");
380 if (*min_usage < 0 || *min_usage > usage) {
382 XBT_HERE(" min_usage=%f (cnst->remaining / cnst->usage =%f)", *min_usage, usage);
383 saturated_constraints.assign(1, cnst_light_num);
384 } else if (*min_usage == usage) {
385 saturated_constraints.emplace_back(cnst_light_num);
389 static inline void saturated_variable_set_update(const ConstraintLight* cnst_light_tab,
390 const dyn_light_t& saturated_constraints, System* sys)
392 /* Add active variables (i.e. variables that need to be set) from the set of constraints to saturate
394 for (int const& saturated_cnst : saturated_constraints) {
395 const ConstraintLight& cnst = cnst_light_tab[saturated_cnst];
396 for (Element const& elem : cnst.cnst->active_element_set_) {
397 xbt_assert(elem.variable->sharing_penalty_ > 0); // All elements of active_element_set should be active
398 if (elem.consumption_weight > 0 && not elem.variable->saturated_variable_set_hook_.is_linked())
399 sys->saturated_variable_set.push_back(*elem.variable);
404 template <class ElemList>
405 static void format_element_list(const ElemList& elem_list, s4u::Link::SharingPolicy sharing_policy, double& sum,
408 for (Element const& elem : elem_list) {
409 buf += std::to_string(elem.consumption_weight) + ".'" + std::to_string(elem.variable->rank_) + "'(" +
410 std::to_string(elem.variable->value_) + ")" +
411 (sharing_policy != s4u::Link::SharingPolicy::FATPIPE ? " + " : " , ");
412 if (sharing_policy != s4u::Link::SharingPolicy::FATPIPE)
413 sum += elem.consumption_weight * elem.variable->value_;
415 sum = std::max(sum, elem.consumption_weight * elem.variable->value_);
419 void System::print() const
421 std::string buf = "MAX-MIN ( ";
423 /* Printing Objective */
424 for (Variable const& var : variable_set)
425 buf += "'" + std::to_string(var.rank_) + "'(" + std::to_string(var.sharing_penalty_) + ") ";
427 XBT_DEBUG("%20s", buf.c_str());
430 XBT_DEBUG("Constraints");
431 /* Printing Constraints */
432 for (Constraint const& cnst : active_constraint_set) {
434 // Show the enabled variables
436 buf += cnst.sharing_policy_ != s4u::Link::SharingPolicy::FATPIPE ? "(" : "max(";
437 format_element_list(cnst.enabled_element_set_, cnst.sharing_policy_, sum, buf);
438 // TODO: Adding disabled elements only for test compatibility, but do we really want them to be printed?
439 format_element_list(cnst.disabled_element_set_, cnst.sharing_policy_, sum, buf);
441 buf += "0) <= " + std::to_string(cnst.bound_) + " ('" + std::to_string(cnst.rank_) + "')";
443 if (cnst.sharing_policy_ == s4u::Link::SharingPolicy::FATPIPE) {
444 buf += " [MAX-Constraint]";
446 XBT_DEBUG("%s", buf.c_str());
448 xbt_assert(not double_positive(sum - cnst.bound_, cnst.bound_ * sg_maxmin_precision),
449 "Incorrect value (%f is not smaller than %f): %g", sum, cnst.bound_, sum - cnst.bound_);
452 XBT_DEBUG("Variables");
453 /* Printing Result */
454 for (Variable const& var : variable_set) {
455 if (var.bound_ > 0) {
456 XBT_DEBUG("'%d'(%f) : %f (<=%f)", var.rank_, var.sharing_penalty_, var.value_, var.bound_);
457 xbt_assert(not double_positive(var.value_ - var.bound_, var.bound_ * sg_maxmin_precision),
458 "Incorrect value (%f is not smaller than %f", var.value_, var.bound_);
460 XBT_DEBUG("'%d'(%f) : %f", var.rank_, var.sharing_penalty_, var.value_);
465 void System::lmm_solve()
468 XBT_IN("(sys=%p)", this);
469 /* Compute Usage and store the variables that reach the maximum. If selective_update_active is true, only
470 * constraints that changed are considered. Otherwise all constraints with active actions are considered.
472 if (selective_update_active)
473 lmm_solve(modified_constraint_set);
475 lmm_solve(active_constraint_set);
480 template <class CnstList> void System::lmm_solve(CnstList& cnst_list)
482 double min_usage = -1;
483 double min_bound = -1;
485 XBT_DEBUG("Active constraints : %zu", cnst_list.size());
486 cnst_light_vec.reserve(cnst_list.size());
487 ConstraintLight* cnst_light_tab = cnst_light_vec.data();
488 int cnst_light_num = 0;
490 for (Constraint& cnst : cnst_list) {
491 /* INIT: Collect constraints that actually need to be saturated (i.e remaining and usage are strictly positive)
492 * into cnst_light_tab. */
493 cnst.remaining_ = cnst.bound_;
494 if (not double_positive(cnst.remaining_, cnst.bound_ * sg_maxmin_precision))
497 for (Element& elem : cnst.enabled_element_set_) {
498 xbt_assert(elem.variable->sharing_penalty_ > 0.0);
499 elem.variable->value_ = 0.0;
500 if (elem.consumption_weight > 0) {
501 if (cnst.sharing_policy_ != s4u::Link::SharingPolicy::FATPIPE)
502 cnst.usage_ += elem.consumption_weight / elem.variable->sharing_penalty_;
503 else if (cnst.usage_ < elem.consumption_weight / elem.variable->sharing_penalty_)
504 cnst.usage_ = elem.consumption_weight / elem.variable->sharing_penalty_;
507 resource::Action* action = elem.variable->id_;
508 if (modified_set_ && not action->is_within_modified_set())
509 modified_set_->push_back(*action);
512 XBT_DEBUG("Constraint '%d' usage: %f remaining: %f concurrency: %i<=%i<=%i", cnst.rank_, cnst.usage_,
513 cnst.remaining_, cnst.concurrency_current_, cnst.concurrency_maximum_, cnst.get_concurrency_limit());
514 /* Saturated constraints update */
516 if (cnst.usage_ > 0) {
517 cnst_light_tab[cnst_light_num].cnst = &cnst;
518 cnst.cnst_light_ = &cnst_light_tab[cnst_light_num];
519 cnst_light_tab[cnst_light_num].remaining_over_usage = cnst.remaining_ / cnst.usage_;
520 saturated_constraints_update(cnst_light_tab[cnst_light_num].remaining_over_usage, cnst_light_num,
521 saturated_constraints, &min_usage);
522 xbt_assert(not cnst.active_element_set_.empty(),
523 "There is no sense adding a constraint that has no active element!");
528 saturated_variable_set_update(cnst_light_tab, saturated_constraints, this);
530 /* Saturated variables update */
532 /* Fix the variables that have to be */
533 auto& var_list = saturated_variable_set;
534 for (Variable const& var : var_list) {
535 if (var.sharing_penalty_ <= 0.0)
537 /* First check if some of these variables could reach their upper bound and update min_bound accordingly. */
538 XBT_DEBUG("var=%d, var.bound=%f, var.penalty=%f, min_usage=%f, var.bound*var.penalty=%f", var.rank_, var.bound_,
539 var.sharing_penalty_, min_usage, var.bound_ * var.sharing_penalty_);
540 if ((var.bound_ > 0) && (var.bound_ * var.sharing_penalty_ < min_usage)) {
542 min_bound = var.bound_ * var.sharing_penalty_;
544 min_bound = std::min(min_bound, (var.bound_ * var.sharing_penalty_));
545 XBT_DEBUG("Updated min_bound=%f", min_bound);
549 while (not var_list.empty()) {
550 Variable& var = var_list.front();
552 // If no variable could reach its bound, deal iteratively the constraints usage ( at worst one constraint is
553 // saturated at each cycle)
554 var.value_ = min_usage / var.sharing_penalty_;
555 XBT_DEBUG("Setting var (%d) value to %f\n", var.rank_, var.value_);
557 // If there exist a variable that can reach its bound, only update it (and other with the same bound) for now.
558 if (double_equals(min_bound, var.bound_ * var.sharing_penalty_, sg_maxmin_precision)) {
559 var.value_ = var.bound_;
560 XBT_DEBUG("Setting %p (%d) value to %f\n", &var, var.rank_, var.value_);
562 // Variables which bound is different are not considered for this cycle, but they will be afterwards.
563 XBT_DEBUG("Do not consider %p (%d) \n", &var, var.rank_);
564 var_list.pop_front();
568 XBT_DEBUG("Min usage: %f, Var(%d).penalty: %f, Var(%d).value: %f ", min_usage, var.rank_, var.sharing_penalty_,
569 var.rank_, var.value_);
571 /* Update the usage of constraints where this variable is involved */
572 for (Element& elem : var.cnsts_) {
573 Constraint* cnst = elem.constraint;
574 if (cnst->sharing_policy_ != s4u::Link::SharingPolicy::FATPIPE) {
575 // Remember: shared constraints require that sum(elem.value * var.value) < cnst->bound
576 double_update(&(cnst->remaining_), elem.consumption_weight * var.value_, cnst->bound_ * sg_maxmin_precision);
577 double_update(&(cnst->usage_), elem.consumption_weight / var.sharing_penalty_, sg_maxmin_precision);
578 // If the constraint is saturated, remove it from the set of active constraints (light_tab)
579 if (not double_positive(cnst->usage_, sg_maxmin_precision) ||
580 not double_positive(cnst->remaining_, cnst->bound_ * sg_maxmin_precision)) {
581 if (cnst->cnst_light_) {
582 int index = (cnst->cnst_light_ - cnst_light_tab);
583 XBT_DEBUG("index: %d \t cnst_light_num: %d \t || usage: %f remaining: %f bound: %f ", index,
584 cnst_light_num, cnst->usage_, cnst->remaining_, cnst->bound_);
585 cnst_light_tab[index] = cnst_light_tab[cnst_light_num - 1];
586 cnst_light_tab[index].cnst->cnst_light_ = &cnst_light_tab[index];
588 cnst->cnst_light_ = nullptr;
591 if (cnst->cnst_light_) {
592 cnst->cnst_light_->remaining_over_usage = cnst->remaining_ / cnst->usage_;
595 elem.make_inactive();
597 // Remember: non-shared constraints only require that max(elem.value * var.value) < cnst->bound
599 elem.make_inactive();
600 for (const Element& elem2 : cnst->enabled_element_set_) {
601 xbt_assert(elem2.variable->sharing_penalty_ > 0);
602 if (elem2.variable->value_ > 0)
604 if (elem2.consumption_weight > 0)
605 cnst->usage_ = std::max(cnst->usage_, elem2.consumption_weight / elem2.variable->sharing_penalty_);
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 || \t cnst: %p \t cnst->cnst_light: %p "
613 "\t cnst_light_tab: %p usage: %f remaining: %f bound: %f ",
614 index, cnst_light_num, cnst, cnst->cnst_light_, cnst_light_tab, cnst->usage_, cnst->remaining_,
616 cnst_light_tab[index] = cnst_light_tab[cnst_light_num - 1];
617 cnst_light_tab[index].cnst->cnst_light_ = &cnst_light_tab[index];
619 cnst->cnst_light_ = nullptr;
622 if (cnst->cnst_light_) {
623 cnst->cnst_light_->remaining_over_usage = cnst->remaining_ / cnst->usage_;
624 xbt_assert(not cnst->active_element_set_.empty(),
625 "Should not keep a maximum constraint that has no active"
626 " element! You want to check the maxmin precision and possible rounding effects.");
631 var_list.pop_front();
634 /* Find out which variables reach the maximum */
637 saturated_constraints.clear();
638 for (int pos = 0; pos < cnst_light_num; pos++) {
639 xbt_assert(not cnst_light_tab[pos].cnst->active_element_set_.empty(),
640 "Cannot saturate more a constraint that has"
641 " no active element! You may want to change the maxmin precision (--cfg=maxmin/precision:<new_value>)"
642 " because of possible rounding effects.\n\tFor the record, the usage of this constraint is %g while "
643 "the maxmin precision to which it is compared is %g.\n\tThe usage of the previous constraint is %g.",
644 cnst_light_tab[pos].cnst->usage_, sg_maxmin_precision, cnst_light_tab[pos - 1].cnst->usage_);
645 saturated_constraints_update(cnst_light_tab[pos].remaining_over_usage, pos, saturated_constraints, &min_usage);
648 saturated_variable_set_update(cnst_light_tab, saturated_constraints, this);
649 } while (cnst_light_num > 0);
652 if (selective_update_active)
653 remove_all_modified_set();
655 if (XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug)) {
662 /** @brief Attribute the value bound to var->bound.
664 * @param var the Variable*
665 * @param bound the new bound to associate with var
667 * Makes var->bound equal to bound. Whenever this function is called a change is signed in the system. To
668 * avoid false system changing detection it is a good idea to test (bound != 0) before calling it.
670 void System::update_variable_bound(Variable* var, double bound)
675 if (not var->cnsts_.empty())
676 update_modified_set(var->cnsts_[0].constraint);
679 void Variable::initialize(resource::Action* id_value, double sharing_penalty, double bound_value,
680 int number_of_constraints, unsigned visited_value)
683 rank_ = next_rank_++;
684 cnsts_.reserve(number_of_constraints);
685 sharing_penalty_ = sharing_penalty;
686 staged_penalty_ = 0.0;
687 bound_ = bound_value;
688 concurrency_share_ = 1;
690 visited_ = visited_value;
693 xbt_assert(not variable_set_hook_.is_linked());
694 xbt_assert(not saturated_variable_set_hook_.is_linked());
697 int Variable::get_min_concurrency_slack() const
699 int minslack = std::numeric_limits<int>::max();
700 for (Element const& elem : cnsts_) {
701 int slack = elem.constraint->get_concurrency_slack();
702 if (slack < minslack) {
703 // This is only an optimization, to avoid looking at more constraints when slack is already zero
712 // Small remark: In this implementation of System::enable_var() and System::disable_var(), we will meet multiple times
713 // with var when running System::update_modified_set().
714 // A priori not a big performance issue, but we might do better by calling System::update_modified_set() within the for
715 // loops (after doing the first for enabling==1, and before doing the last for disabling==1)
716 void System::enable_var(Variable* var)
718 xbt_assert(not XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug) || var->can_enable());
720 var->sharing_penalty_ = var->staged_penalty_;
721 var->staged_penalty_ = 0;
723 // Enabling the variable, move var to list head. Subtlety is: here, we need to call update_modified_set AFTER
724 // moving at least one element of var.
726 simgrid::xbt::intrusive_erase(variable_set, *var);
727 variable_set.push_front(*var);
728 for (Element& elem : var->cnsts_) {
729 simgrid::xbt::intrusive_erase(elem.constraint->disabled_element_set_, elem);
730 elem.constraint->enabled_element_set_.push_front(elem);
731 elem.increase_concurrency();
733 if (not var->cnsts_.empty())
734 update_modified_set(var->cnsts_[0].constraint);
736 // When used within on_disabled_var, we would get an assertion fail, because transiently there can be variables
737 // that are staged and could be activated.
738 // Anyway, caller functions all call check_concurrency() in the end.
741 void System::disable_var(Variable* var)
743 xbt_assert(not var->staged_penalty_, "Staged penalty should have been cleared");
744 // Disabling the variable, move to var to list tail. Subtlety is: here, we need to call update_modified_set
745 // BEFORE moving the last element of var.
746 simgrid::xbt::intrusive_erase(variable_set, *var);
747 variable_set.push_back(*var);
748 if (not var->cnsts_.empty())
749 update_modified_set(var->cnsts_[0].constraint);
750 for (Element& elem : var->cnsts_) {
751 simgrid::xbt::intrusive_erase(elem.constraint->enabled_element_set_, elem);
752 elem.constraint->disabled_element_set_.push_back(elem);
753 if (elem.active_element_set_hook.is_linked())
754 simgrid::xbt::intrusive_erase(elem.constraint->active_element_set_, elem);
755 elem.decrease_concurrency();
758 var->sharing_penalty_ = 0.0;
759 var->staged_penalty_ = 0.0;
764 /* /brief Find variables that can be enabled and enable them.
766 * Assuming that the variable has already been removed from non-zero penalties
767 * Can we find a staged variable to add?
768 * If yes, check that none of the constraints that this variable is involved in is at the limit of its concurrency
769 * And then add it to enabled variables
771 void System::on_disabled_var(Constraint* cnstr)
773 if (cnstr->get_concurrency_limit() < 0)
776 int numelem = cnstr->disabled_element_set_.size();
780 Element* elem = &cnstr->disabled_element_set_.front();
782 // Cannot use foreach loop, because System::enable_var() will modify disabled_element_set.. within the loop
783 while (numelem-- && elem) {
785 if (elem->disabled_element_set_hook.is_linked()) {
786 auto iter = std::next(cnstr->disabled_element_set_.iterator_to(*elem));
787 nextelem = iter != std::end(cnstr->disabled_element_set_) ? &*iter : nullptr;
792 if (elem->variable->staged_penalty_ > 0 && elem->variable->can_enable()) {
793 // Found a staged variable
794 // TODOLATER: Add random timing function to model reservation protocol fuzziness? Then how to make sure that
795 // staged variables will eventually be called?
796 enable_var(elem->variable);
799 xbt_assert(cnstr->concurrency_current_ <= cnstr->get_concurrency_limit(), "Concurrency overflow!");
800 if (cnstr->concurrency_current_ == cnstr->get_concurrency_limit())
806 // We could get an assertion fail, because transiently there can be variables that are staged and could be activated.
807 // And we need to go through all constraints of the disabled var before getting back a coherent state.
808 // Anyway, caller functions all call check_concurrency() in the end.
811 /** @brief update the penalty of a variable (disable it by passing 0 as a penalty) */
812 void System::update_variable_penalty(Variable* var, double penalty)
814 xbt_assert(penalty >= 0, "Variable penalty should not be negative!");
816 if (penalty == var->sharing_penalty_)
819 bool enabling_var = (penalty > 0 && var->sharing_penalty_ <= 0);
820 bool disabling_var = (penalty <= 0 && var->sharing_penalty_ > 0);
822 XBT_IN("(sys=%p, var=%p, penalty=%f)", this, var, penalty);
826 // Are we enabling this variable?
828 var->staged_penalty_ = penalty;
829 int minslack = var->get_min_concurrency_slack();
830 if (minslack < var->concurrency_share_) {
831 XBT_DEBUG("Staging var (instead of enabling) because min concurrency slack %i, with penalty %f and concurrency"
833 minslack, penalty, var->concurrency_share_);
836 XBT_DEBUG("Enabling var with min concurrency slack %i", minslack);
838 } else if (disabling_var) {
841 var->sharing_penalty_ = penalty;
849 void System::update_constraint_bound(Constraint* cnst, double bound)
852 update_modified_set(cnst);
853 cnst->bound_ = bound;
856 /** @brief Update the constraint set propagating recursively to other constraints so the system should not be entirely
859 * @param cnst the Constraint* affected by the change
861 * A recursive algorithm to optimize the system recalculation selecting only constraints that have changed. Each
862 * constraint change is propagated to the list of constraints for each variable.
864 void System::update_modified_set_rec(const Constraint* cnst)
866 for (Element const& elem : cnst->enabled_element_set_) {
867 Variable* var = elem.variable;
868 for (Element const& elem2 : var->cnsts_) {
869 if (var->visited_ == visited_counter_)
871 if (elem2.constraint != cnst && not elem2.constraint->modified_constraint_set_hook_.is_linked()) {
872 modified_constraint_set.push_back(*elem2.constraint);
873 update_modified_set_rec(elem2.constraint);
876 // var will be ignored in later visits as long as sys->visited_counter does not move
877 var->visited_ = visited_counter_;
881 void System::update_modified_set(Constraint* cnst)
883 /* nothing to do if selective update isn't active */
884 if (selective_update_active && not cnst->modified_constraint_set_hook_.is_linked()) {
885 modified_constraint_set.push_back(*cnst);
886 update_modified_set_rec(cnst);
890 void System::remove_all_modified_set()
892 // We cleverly un-flag all variables just by incrementing visited_counter
893 // In effect, the var->visited value will no more be equal to visited counter
894 // To be clean, when visited counter has wrapped around, we force these var->visited values so that variables that
895 // were in the modified a long long time ago are not wrongly skipped here, which would lead to very nasty bugs
896 // (i.e. not readily reproducible, and requiring a lot of run time before happening).
897 if (++visited_counter_ == 1) {
898 /* the counter wrapped around, reset each variable->visited */
899 for (Variable& var : variable_set)
902 modified_constraint_set.clear();
906 * Returns resource load (in flop per second, or byte per second, or similar)
908 * If the resource is shared (the default case), the load is sum of resource usage made by
909 * every variables located on this resource.
911 * If the resource is not shared (ie in FATPIPE mode), then the load is the max (not the sum)
912 * of all resource usages located on this resource.
914 double Constraint::get_usage() const
917 if (sharing_policy_ != s4u::Link::SharingPolicy::FATPIPE) {
918 for (Element const& elem : enabled_element_set_)
919 if (elem.consumption_weight > 0)
920 result += elem.consumption_weight * elem.variable->value_;
922 for (Element const& elem : enabled_element_set_)
923 if (elem.consumption_weight > 0)
924 result = std::max(result, elem.consumption_weight * elem.variable->value_);
929 int Constraint::get_variable_amount() const
931 return static_cast<int>(std::count_if(std::begin(enabled_element_set_), std::end(enabled_element_set_),
932 [](const Element& elem) { return elem.consumption_weight > 0; }));
936 } // namespace kernel
937 } // namespace simgrid