1 /* Copyright (c) 2004-2017. 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 /* \file callbacks.h */
8 #include "src/kernel/lmm/maxmin.hpp"
9 #include "xbt/backtrace.hpp"
11 #include "xbt/mallocator.h"
12 #include "xbt/sysdep.h"
13 #include "xbt/utility.hpp"
21 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(surf_maxmin, surf, "Logging specific to SURF (maxmin)");
23 double sg_maxmin_precision = 0.00001; /* Change this with --cfg=maxmin/precision:VALUE */
24 double sg_surf_precision = 0.00001; /* Change this with --cfg=surf/precision:VALUE */
25 int sg_concurrency_limit = -1; /* Change this with --cfg=maxmin/concurrency-limit:VALUE */
31 typedef std::vector<int> dyn_light_t;
33 int Variable::Global_debug_id = 1;
34 int Constraint::Global_debug_id = 1;
36 int Element::get_concurrency() const
38 // Ignore element with weight less than one (e.g. cross-traffic)
39 return (consumption_weight >= 1) ? 1 : 0;
40 // There are other alternatives, but they will change the behaviour of the model..
41 // So do not use it unless you want to make a new model.
42 // If you do, remember to change the variables concurrency share to reflect it.
43 // Potential examples are:
44 // return (elem->weight>0)?1:0;//Include element as soon as weight is non-zero
45 // return (int)ceil(elem->weight);//Include element as the rounded-up integer value of the element weight
48 void Element::decrease_concurrency()
50 xbt_assert(constraint->concurrency_current >= get_concurrency());
51 constraint->concurrency_current -= get_concurrency();
54 void Element::increase_concurrency()
56 constraint->concurrency_current += get_concurrency();
58 if (constraint->concurrency_current > constraint->concurrency_maximum)
59 constraint->concurrency_maximum = constraint->concurrency_current;
61 xbt_assert(constraint->get_concurrency_limit() < 0 ||
62 constraint->concurrency_current <= constraint->get_concurrency_limit(),
63 "Concurrency limit overflow!");
66 void System::check_concurrency() const
68 // These checks are very expensive, so do them only if we want to debug SURF LMM
69 if (not XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug))
72 for (Constraint const& cnst : constraint_set) {
74 for (Element const& elem : cnst.enabled_element_set) {
75 xbt_assert(elem.variable->sharing_weight > 0);
76 concurrency += elem.get_concurrency();
79 for (Element const& elem : cnst.disabled_element_set) {
80 // We should have staged variables only if concurrency is reached in some constraint
81 xbt_assert(cnst.get_concurrency_limit() < 0 || elem.variable->staged_weight == 0 ||
82 elem.variable->get_min_concurrency_slack() < elem.variable->concurrency_share,
83 "should not have staged variable!");
86 xbt_assert(cnst.get_concurrency_limit() < 0 || cnst.get_concurrency_limit() >= concurrency,
87 "concurrency check failed!");
88 xbt_assert(cnst.concurrency_current == concurrency, "concurrency_current is out-of-date!");
91 // Check that for each variable, all corresponding elements are in the same state (i.e. same element sets)
92 for (Variable const& var : variable_set) {
93 if (var.cnsts.empty())
96 const Element& elem = var.cnsts[0];
97 int belong_to_enabled = elem.enabled_element_set_hook.is_linked();
98 int belong_to_disabled = elem.disabled_element_set_hook.is_linked();
99 int belong_to_active = elem.active_element_set_hook.is_linked();
101 for (Element const& elem2 : var.cnsts) {
102 xbt_assert(belong_to_enabled == elem2.enabled_element_set_hook.is_linked(),
103 "Variable inconsistency (1): enabled_element_set");
104 xbt_assert(belong_to_disabled == elem2.disabled_element_set_hook.is_linked(),
105 "Variable inconsistency (2): disabled_element_set");
106 xbt_assert(belong_to_active == elem2.active_element_set_hook.is_linked(),
107 "Variable inconsistency (3): active_element_set");
112 void System::var_free(Variable* var)
114 XBT_IN("(sys=%p, var=%p)", this, var);
117 // TODOLATER Can do better than that by leaving only the variable in only one enabled_element_set, call
118 // update_modified_set, and then remove it..
119 if (not var->cnsts.empty())
120 update_modified_set(var->cnsts[0].constraint);
122 for (Element& elem : var->cnsts) {
123 if (var->sharing_weight > 0)
124 elem.decrease_concurrency();
125 if (elem.enabled_element_set_hook.is_linked())
126 simgrid::xbt::intrusive_erase(elem.constraint->enabled_element_set, elem);
127 if (elem.disabled_element_set_hook.is_linked())
128 simgrid::xbt::intrusive_erase(elem.constraint->disabled_element_set, elem);
129 if (elem.active_element_set_hook.is_linked())
130 simgrid::xbt::intrusive_erase(elem.constraint->active_element_set, elem);
131 int nelements = elem.constraint->enabled_element_set.size() + elem.constraint->disabled_element_set.size();
133 make_constraint_inactive(elem.constraint);
135 on_disabled_var(elem.constraint);
142 xbt_mallocator_release(variable_mallocator, var);
146 System::System(bool selective_update) : selective_update_active(selective_update)
151 XBT_DEBUG("Setting selective_update_active flag to %d", selective_update_active);
153 keep_track = nullptr;
154 variable_mallocator =
155 xbt_mallocator_new(65536, System::variable_mallocator_new_f, System::variable_mallocator_free_f, nullptr);
156 solve_fun = &lmm_solve;
164 while ((var = extract_variable())) {
165 auto demangled = simgrid::xbt::demangle(typeid(*var->id).name());
166 XBT_WARN("Probable bug: a %s variable (#%d) not removed before the LMM system destruction.", demangled.get(),
170 while ((cnst = extract_constraint()))
173 xbt_mallocator_free(variable_mallocator);
176 void System::cnst_free(Constraint* cnst)
178 make_constraint_inactive(cnst);
182 Constraint::Constraint(void* id_value, double bound_value) : bound(bound_value), id(id_value)
184 id_int = Global_debug_id++;
188 concurrency_limit = sg_concurrency_limit;
189 concurrency_current = 0;
190 concurrency_maximum = 0;
191 sharing_policy = 1; /* FIXME: don't hardcode the value */
195 cnst_light = nullptr;
198 Constraint* System::constraint_new(void* id, double bound_value)
200 Constraint* cnst = new Constraint(id, bound_value);
201 insert_constraint(cnst);
205 void* System::variable_mallocator_new_f()
210 void System::variable_mallocator_free_f(void* var)
212 delete static_cast<Variable*>(var);
215 Variable* System::variable_new(simgrid::kernel::resource::Action* id, double sharing_weight, double bound,
216 int number_of_constraints)
218 XBT_IN("(sys=%p, id=%p, weight=%f, bound=%f, num_cons =%d)", this, id, sharing_weight, bound, number_of_constraints);
220 Variable* var = static_cast<Variable*>(xbt_mallocator_get(variable_mallocator));
221 var->initialize(id, sharing_weight, bound, number_of_constraints, visited_counter - 1);
223 variable_set.push_front(*var);
225 variable_set.push_back(*var);
227 XBT_OUT(" returns %p", var);
231 void System::variable_free(Variable* var)
233 remove_variable(var);
237 void System::expand(Constraint* cnst, Variable* var, double consumption_weight)
241 // Check if this variable already has an active element in this constraint
242 // If it does, substract it from the required slack
243 int current_share = 0;
244 if (var->concurrency_share > 1) {
245 for (Element& elem : var->cnsts) {
246 if (elem.constraint == cnst && elem.enabled_element_set_hook.is_linked())
247 current_share += elem.get_concurrency();
251 // Check if we need to disable the variable
252 if (var->sharing_weight > 0 && var->concurrency_share - current_share > cnst->get_concurrency_slack()) {
253 double weight = var->sharing_weight;
255 for (Element const& elem : var->cnsts)
256 on_disabled_var(elem.constraint);
257 consumption_weight = 0;
258 var->staged_weight = weight;
259 xbt_assert(not var->sharing_weight);
262 xbt_assert(var->cnsts.size() < var->cnsts.capacity(), "Too much constraints");
264 var->cnsts.resize(var->cnsts.size() + 1);
265 Element& elem = var->cnsts.back();
267 elem.consumption_weight = consumption_weight;
268 elem.constraint = cnst;
271 if (var->sharing_weight) {
272 elem.constraint->enabled_element_set.push_front(elem);
273 elem.increase_concurrency();
275 elem.constraint->disabled_element_set.push_back(elem);
277 if (not selective_update_active) {
278 make_constraint_active(cnst);
279 } else if (elem.consumption_weight > 0 || var->sharing_weight > 0) {
280 make_constraint_active(cnst);
281 update_modified_set(cnst);
282 // TODOLATER: Why do we need this second call?
283 if (var->cnsts.size() > 1)
284 update_modified_set(var->cnsts[0].constraint);
290 void System::expand_add(Constraint* cnst, Variable* var, double value)
296 // BEWARE: In case you have multiple elements in one constraint, this will always add value to the first element.
298 std::find_if(begin(var->cnsts), end(var->cnsts), [&cnst](Element const& x) { return x.constraint == cnst; });
299 if (elem_it != end(var->cnsts)) {
300 Element& elem = *elem_it;
301 if (var->sharing_weight)
302 elem.decrease_concurrency();
304 if (cnst->sharing_policy)
305 elem.consumption_weight += value;
307 elem.consumption_weight = std::max(elem.consumption_weight, value);
309 // We need to check that increasing value of the element does not cross the concurrency limit
310 if (var->sharing_weight) {
311 if (cnst->get_concurrency_slack() < elem.get_concurrency()) {
312 double weight = var->sharing_weight;
314 for (Element const& elem2 : var->cnsts)
315 on_disabled_var(elem2.constraint);
316 var->staged_weight = weight;
317 xbt_assert(not var->sharing_weight);
319 elem.increase_concurrency();
321 update_modified_set(cnst);
323 expand(cnst, var, value);
328 Variable* Constraint::get_variable(const_lmm_element_t* elem) const
330 if (*elem == nullptr) {
331 // That is the first call, pick the first element among enabled_element_set (or disabled_element_set if
332 // enabled_element_set is empty)
333 if (not enabled_element_set.empty())
334 *elem = &enabled_element_set.front();
335 else if (not disabled_element_set.empty())
336 *elem = &disabled_element_set.front();
340 // elem is not null, so we carry on
341 if ((*elem)->enabled_element_set_hook.is_linked()) {
342 // Look at enabled_element_set, and jump to disabled_element_set when finished
343 auto iter = std::next(enabled_element_set.iterator_to(**elem));
344 if (iter != std::end(enabled_element_set))
346 else if (not disabled_element_set.empty())
347 *elem = &disabled_element_set.front();
351 auto iter = std::next(disabled_element_set.iterator_to(**elem));
352 *elem = iter != std::end(disabled_element_set) ? &*iter : nullptr;
356 return (*elem)->variable;
361 // if we modify the list between calls, normal version may loop forever
362 // this safe version ensures that we browse the list elements only once
363 Variable* Constraint::get_variable_safe(const_lmm_element_t* elem, const_lmm_element_t* nextelem, int* numelem) const
365 if (*elem == nullptr) {
366 *numelem = enabled_element_set.size() + disabled_element_set.size() - 1;
367 if (not enabled_element_set.empty())
368 *elem = &enabled_element_set.front();
369 else if (not disabled_element_set.empty())
370 *elem = &disabled_element_set.front();
381 // elem is not null, so we carry on
382 if ((*elem)->enabled_element_set_hook.is_linked()) {
383 // Look at enabled_element_set, and jump to disabled_element_set when finished
384 auto iter = std::next(enabled_element_set.iterator_to(**elem));
385 if (iter != std::end(enabled_element_set))
387 else if (not disabled_element_set.empty())
388 *nextelem = &disabled_element_set.front();
392 auto iter = std::next(disabled_element_set.iterator_to(**elem));
393 *nextelem = iter != std::end(disabled_element_set) ? &*iter : nullptr;
395 return (*elem)->variable;
400 static inline void saturated_constraints_update(double usage, int cnst_light_num, dyn_light_t& saturated_constraints,
403 xbt_assert(usage > 0, "Impossible");
405 if (*min_usage < 0 || *min_usage > usage) {
407 XBT_HERE(" min_usage=%f (cnst->remaining / cnst->usage =%f)", *min_usage, usage);
408 saturated_constraints.assign(1, cnst_light_num);
409 } else if (*min_usage == usage) {
410 saturated_constraints.emplace_back(cnst_light_num);
414 static inline void saturated_variable_set_update(ConstraintLight* cnst_light_tab,
415 const dyn_light_t& saturated_constraints, lmm_system_t sys)
417 /* Add active variables (i.e. variables that need to be set) from the set of constraints to saturate
419 for (int const& saturated_cnst : saturated_constraints) {
420 ConstraintLight& cnst = cnst_light_tab[saturated_cnst];
421 for (Element const& elem : cnst.cnst->active_element_set) {
422 // Visiting active_element_set, so, by construction, should never get a zero weight, correct?
423 xbt_assert(elem.variable->sharing_weight > 0);
424 if (elem.consumption_weight > 0 && not elem.variable->saturated_variable_set_hook.is_linked())
425 sys->saturated_variable_set.push_back(*elem.variable);
430 template <class ElemList>
431 static void format_element_list(const ElemList& elem_list, int sharing_policy, double& sum, std::string& buf)
433 for (Element const& elem : elem_list) {
434 buf += std::to_string(elem.consumption_weight) + ".'" + std::to_string(elem.variable->id_int) + "'(" +
435 std::to_string(elem.variable->value) + ")" + (sharing_policy ? " + " : " , ");
437 sum += elem.consumption_weight * elem.variable->value;
439 sum = std::max(sum, elem.consumption_weight * elem.variable->value);
443 void System::print() const
445 std::string buf = std::string("MAX-MIN ( ");
447 /* Printing Objective */
448 for (Variable const& var : variable_set)
449 buf += "'" + std::to_string(var.id_int) + "'(" + std::to_string(var.sharing_weight) + ") ";
451 XBT_DEBUG("%20s", buf.c_str());
454 XBT_DEBUG("Constraints");
455 /* Printing Constraints */
456 for (Constraint const& cnst : active_constraint_set) {
458 // Show the enabled variables
460 buf += cnst.sharing_policy ? "(" : "max(";
461 format_element_list(cnst.enabled_element_set, cnst.sharing_policy, sum, buf);
462 // TODO: Adding disabled elements only for test compatibility, but do we really want them to be printed?
463 format_element_list(cnst.disabled_element_set, cnst.sharing_policy, sum, buf);
465 buf += "0) <= " + std::to_string(cnst.bound) + " ('" + std::to_string(cnst.id_int) + "')";
467 if (not cnst.sharing_policy) {
468 buf += " [MAX-Constraint]";
470 XBT_DEBUG("%s", buf.c_str());
472 xbt_assert(not double_positive(sum - cnst.bound, cnst.bound * sg_maxmin_precision),
473 "Incorrect value (%f is not smaller than %f): %g", sum, cnst.bound, sum - cnst.bound);
476 XBT_DEBUG("Variables");
477 /* Printing Result */
478 for (Variable const& var : variable_set) {
480 XBT_DEBUG("'%d'(%f) : %f (<=%f)", var.id_int, var.sharing_weight, var.value, var.bound);
481 xbt_assert(not double_positive(var.value - var.bound, var.bound * sg_maxmin_precision),
482 "Incorrect value (%f is not smaller than %f", var.value, var.bound);
484 XBT_DEBUG("'%d'(%f) : %f", var.id_int, var.sharing_weight, var.value);
492 XBT_IN("(sys=%p)", this);
493 /* Compute Usage and store the variables that reach the maximum. If selective_update_active is true, only
494 * constraints that changed are considered. Otherwise all constraints with active actions are considered.
496 if (selective_update_active)
497 solve(modified_constraint_set);
499 solve(active_constraint_set);
504 template <class CnstList> void System::solve(CnstList& cnst_list)
506 double min_usage = -1;
507 double min_bound = -1;
509 XBT_DEBUG("Active constraints : %zu", cnst_list.size());
510 /* Init: Only modified code portions: reset the value of active variables */
511 for (Constraint const& cnst : cnst_list) {
512 for (Element const& elem : cnst.enabled_element_set) {
513 xbt_assert(elem.variable->sharing_weight > 0.0);
514 elem.variable->value = 0.0;
518 ConstraintLight* cnst_light_tab = new ConstraintLight[cnst_list.size()]();
519 int cnst_light_num = 0;
520 dyn_light_t saturated_constraints;
522 for (Constraint& cnst : cnst_list) {
523 /* INIT: Collect constraints that actually need to be saturated (i.e remaining and usage are strictly positive)
524 * into cnst_light_tab. */
525 cnst.remaining = cnst.bound;
526 if (not double_positive(cnst.remaining, cnst.bound * sg_maxmin_precision))
529 for (Element& elem : cnst.enabled_element_set) {
530 xbt_assert(elem.variable->sharing_weight > 0);
531 if (elem.consumption_weight > 0) {
532 if (cnst.sharing_policy)
533 cnst.usage += elem.consumption_weight / elem.variable->sharing_weight;
534 else if (cnst.usage < elem.consumption_weight / elem.variable->sharing_weight)
535 cnst.usage = elem.consumption_weight / elem.variable->sharing_weight;
538 simgrid::kernel::resource::Action* action = static_cast<simgrid::kernel::resource::Action*>(elem.variable->id);
539 if (keep_track && not action->isLinkedModifiedSet())
540 keep_track->push_back(*action);
543 XBT_DEBUG("Constraint '%d' usage: %f remaining: %f concurrency: %i<=%i<=%i", cnst.id_int, cnst.usage,
544 cnst.remaining, cnst.concurrency_current, cnst.concurrency_maximum, cnst.get_concurrency_limit());
545 /* Saturated constraints update */
547 if (cnst.usage > 0) {
548 cnst_light_tab[cnst_light_num].cnst = &cnst;
549 cnst.cnst_light = &cnst_light_tab[cnst_light_num];
550 cnst_light_tab[cnst_light_num].remaining_over_usage = cnst.remaining / cnst.usage;
551 saturated_constraints_update(cnst_light_tab[cnst_light_num].remaining_over_usage, cnst_light_num,
552 saturated_constraints, &min_usage);
553 xbt_assert(not cnst.active_element_set.empty(),
554 "There is no sense adding a constraint that has no active element!");
559 saturated_variable_set_update(cnst_light_tab, saturated_constraints, this);
561 /* Saturated variables update */
563 /* Fix the variables that have to be */
564 auto& var_list = saturated_variable_set;
565 for (Variable const& var : var_list) {
566 if (var.sharing_weight <= 0.0)
568 /* First check if some of these variables could reach their upper bound and update min_bound accordingly. */
569 XBT_DEBUG("var=%d, var.bound=%f, var.weight=%f, min_usage=%f, var.bound*var.weight=%f", var.id_int, var.bound,
570 var.sharing_weight, min_usage, var.bound * var.sharing_weight);
571 if ((var.bound > 0) && (var.bound * var.sharing_weight < min_usage)) {
573 min_bound = var.bound * var.sharing_weight;
575 min_bound = std::min(min_bound, (var.bound * var.sharing_weight));
576 XBT_DEBUG("Updated min_bound=%f", min_bound);
580 while (not var_list.empty()) {
581 Variable& var = var_list.front();
583 // If no variable could reach its bound, deal iteratively the constraints usage ( at worst one constraint is
584 // saturated at each cycle)
585 var.value = min_usage / var.sharing_weight;
586 XBT_DEBUG("Setting var (%d) value to %f\n", var.id_int, var.value);
588 // If there exist a variable that can reach its bound, only update it (and other with the same bound) for now.
589 if (double_equals(min_bound, var.bound * var.sharing_weight, sg_maxmin_precision)) {
590 var.value = var.bound;
591 XBT_DEBUG("Setting %p (%d) value to %f\n", &var, var.id_int, var.value);
593 // Variables which bound is different are not considered for this cycle, but they will be afterwards.
594 XBT_DEBUG("Do not consider %p (%d) \n", &var, var.id_int);
595 var_list.pop_front();
599 XBT_DEBUG("Min usage: %f, Var(%d).weight: %f, Var(%d).value: %f ", min_usage, var.id_int, var.sharing_weight,
600 var.id_int, var.value);
602 /* Update the usage of contraints where this variable is involved */
603 for (Element& elem : var.cnsts) {
604 Constraint* cnst = elem.constraint;
605 if (cnst->sharing_policy) {
606 // Remember: shared constraints require that sum(elem.value * var.value) < cnst->bound
607 double_update(&(cnst->remaining), elem.consumption_weight * var.value, cnst->bound * sg_maxmin_precision);
608 double_update(&(cnst->usage), elem.consumption_weight / var.sharing_weight, sg_maxmin_precision);
609 // If the constraint is saturated, remove it from the set of active constraints (light_tab)
610 if (not double_positive(cnst->usage, sg_maxmin_precision) ||
611 not double_positive(cnst->remaining, cnst->bound * sg_maxmin_precision)) {
612 if (cnst->cnst_light) {
613 int index = (cnst->cnst_light - cnst_light_tab);
614 XBT_DEBUG("index: %d \t cnst_light_num: %d \t || usage: %f remaining: %f bound: %f ", index,
615 cnst_light_num, cnst->usage, cnst->remaining, cnst->bound);
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 cnst->cnst_light->remaining_over_usage = cnst->remaining / cnst->usage;
624 elem.make_inactive();
626 // Remember: non-shared constraints only require that max(elem.value * var.value) < cnst->bound
628 elem.make_inactive();
629 for (Element& elem2 : cnst->enabled_element_set) {
630 xbt_assert(elem2.variable->sharing_weight > 0);
631 if (elem2.variable->value > 0)
633 if (elem2.consumption_weight > 0)
634 cnst->usage = std::max(cnst->usage, elem2.consumption_weight / elem2.variable->sharing_weight);
636 // If the constraint is saturated, remove it from the set of active constraints (light_tab)
637 if (not double_positive(cnst->usage, sg_maxmin_precision) ||
638 not double_positive(cnst->remaining, cnst->bound * sg_maxmin_precision)) {
639 if (cnst->cnst_light) {
640 int index = (cnst->cnst_light - cnst_light_tab);
641 XBT_DEBUG("index: %d \t cnst_light_num: %d \t || \t cnst: %p \t cnst->cnst_light: %p "
642 "\t cnst_light_tab: %p usage: %f remaining: %f bound: %f ",
643 index, cnst_light_num, cnst, cnst->cnst_light, cnst_light_tab, cnst->usage, cnst->remaining,
645 cnst_light_tab[index] = cnst_light_tab[cnst_light_num - 1];
646 cnst_light_tab[index].cnst->cnst_light = &cnst_light_tab[index];
648 cnst->cnst_light = nullptr;
651 cnst->cnst_light->remaining_over_usage = cnst->remaining / cnst->usage;
652 xbt_assert(not cnst->active_element_set.empty(),
653 "Should not keep a maximum constraint that has no active"
654 " element! You want to check the maxmin precision and possible rounding effects.");
658 var_list.pop_front();
661 /* Find out which variables reach the maximum */
664 saturated_constraints.clear();
666 for (pos = 0; pos < cnst_light_num; pos++) {
667 xbt_assert(not cnst_light_tab[pos].cnst->active_element_set.empty(),
668 "Cannot saturate more a constraint that has"
669 " no active element! You may want to change the maxmin precision (--cfg=maxmin/precision:<new_value>)"
670 " because of possible rounding effects.\n\tFor the record, the usage of this constraint is %g while "
671 "the maxmin precision to which it is compared is %g.\n\tThe usage of the previous constraint is %g.",
672 cnst_light_tab[pos].cnst->usage, sg_maxmin_precision, cnst_light_tab[pos - 1].cnst->usage);
673 saturated_constraints_update(cnst_light_tab[pos].remaining_over_usage, pos, saturated_constraints, &min_usage);
676 saturated_variable_set_update(cnst_light_tab, saturated_constraints, this);
678 } while (cnst_light_num > 0);
681 if (selective_update_active)
682 remove_all_modified_set();
684 if (XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug)) {
690 delete[] cnst_light_tab;
693 void lmm_solve(lmm_system_t sys)
698 /** \brief Attribute the value bound to var->bound.
700 * \param var the Variable*
701 * \param bound the new bound to associate with var
703 * Makes var->bound equal to bound. Whenever this function is called a change is signed in the system. To
704 * avoid false system changing detection it is a good idea to test (bound != 0) before calling it.
706 void System::update_variable_bound(Variable* var, double bound)
711 if (not var->cnsts.empty())
712 update_modified_set(var->cnsts[0].constraint);
715 void Variable::initialize(simgrid::kernel::resource::Action* id_value, double sharing_weight_value, double bound_value,
716 int number_of_constraints, unsigned visited_value)
719 id_int = Global_debug_id++;
720 cnsts.reserve(number_of_constraints);
721 sharing_weight = sharing_weight_value;
724 concurrency_share = 1;
726 visited = visited_value;
730 func_fp = func_fp_def;
731 func_fpi = func_fpi_def;
733 xbt_assert(not variable_set_hook.is_linked());
734 xbt_assert(not saturated_variable_set_hook.is_linked());
737 int Variable::get_min_concurrency_slack() const
739 int minslack = std::numeric_limits<int>::max();
740 for (Element const& elem : cnsts) {
741 int slack = elem.constraint->get_concurrency_slack();
742 if (slack < minslack) {
743 // This is only an optimization, to avoid looking at more constraints when slack is already zero
752 // Small remark: In this implementation of System::enable_var() and System::disable_var(), we will meet multiple times
753 // with var when running System::update_modified_set().
754 // A priori not a big performance issue, but we might do better by calling System::update_modified_set() within the for
755 // loops (after doing the first for enabling==1, and before doing the last for disabling==1)
756 void System::enable_var(Variable* var)
758 xbt_assert(not XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug) || var->can_enable());
760 var->sharing_weight = var->staged_weight;
761 var->staged_weight = 0;
763 // Enabling the variable, move var to list head. Subtlety is: here, we need to call update_modified_set AFTER
764 // moving at least one element of var.
766 simgrid::xbt::intrusive_erase(variable_set, *var);
767 variable_set.push_front(*var);
768 for (Element& elem : var->cnsts) {
769 simgrid::xbt::intrusive_erase(elem.constraint->disabled_element_set, elem);
770 elem.constraint->enabled_element_set.push_front(elem);
771 elem.increase_concurrency();
773 if (not var->cnsts.empty())
774 update_modified_set(var->cnsts[0].constraint);
776 // When used within on_disabled_var, we would get an assertion fail, because transiently there can be variables
777 // that are staged and could be activated.
778 // Anyway, caller functions all call check_concurrency() in the end.
781 void System::disable_var(Variable* var)
783 xbt_assert(not var->staged_weight, "Staged weight should have been cleared");
784 // Disabling the variable, move to var to list tail. Subtlety is: here, we need to call update_modified_set
785 // BEFORE moving the last element of var.
786 simgrid::xbt::intrusive_erase(variable_set, *var);
787 variable_set.push_back(*var);
788 if (not var->cnsts.empty())
789 update_modified_set(var->cnsts[0].constraint);
790 for (Element& elem : var->cnsts) {
791 simgrid::xbt::intrusive_erase(elem.constraint->enabled_element_set, elem);
792 elem.constraint->disabled_element_set.push_back(elem);
793 if (elem.active_element_set_hook.is_linked())
794 simgrid::xbt::intrusive_erase(elem.constraint->active_element_set, elem);
795 elem.decrease_concurrency();
798 var->sharing_weight = 0.0;
799 var->staged_weight = 0.0;
804 /* /brief Find variables that can be enabled and enable them.
806 * Assuming that the variable has already been removed from non-zero weights
807 * Can we find a staged variable to add?
808 * If yes, check that none of the constraints that this variable is involved in is at the limit of its concurrency
809 * And then add it to enabled variables
811 void System::on_disabled_var(Constraint* cnstr)
813 if (cnstr->get_concurrency_limit() < 0)
816 int numelem = cnstr->disabled_element_set.size();
820 lmm_element_t elem = &cnstr->disabled_element_set.front();
822 // Cannot use foreach loop, because System::enable_var() will modify disabled_element_set.. within the loop
823 while (numelem-- && elem) {
825 lmm_element_t nextelem;
826 if (elem->disabled_element_set_hook.is_linked()) {
827 auto iter = std::next(cnstr->disabled_element_set.iterator_to(*elem));
828 nextelem = iter != std::end(cnstr->disabled_element_set) ? &*iter : nullptr;
833 if (elem->variable->staged_weight > 0 && elem->variable->can_enable()) {
834 // Found a staged variable
835 // TODOLATER: Add random timing function to model reservation protocol fuzziness? Then how to make sure that
836 // staged variables will eventually be called?
837 enable_var(elem->variable);
840 xbt_assert(cnstr->concurrency_current <= cnstr->get_concurrency_limit(), "Concurrency overflow!");
841 if (cnstr->concurrency_current == cnstr->get_concurrency_limit())
847 // We could get an assertion fail, because transiently there can be variables that are staged and could be activated.
848 // And we need to go through all constraints of the disabled var before getting back a coherent state.
849 // Anyway, caller functions all call check_concurrency() in the end.
852 /* \brief update the weight of a variable, and enable/disable it.
853 * @return Returns whether a change was made
855 void System::update_variable_weight(Variable* var, double weight)
857 xbt_assert(weight >= 0, "Variable weight should not be negative!");
859 if (weight == var->sharing_weight)
862 int enabling_var = (weight > 0 && var->sharing_weight <= 0);
863 int disabling_var = (weight <= 0 && var->sharing_weight > 0);
865 XBT_IN("(sys=%p, var=%p, weight=%f)", this, var, weight);
869 // Are we enabling this variable?
871 var->staged_weight = weight;
872 int minslack = var->get_min_concurrency_slack();
873 if (minslack < var->concurrency_share) {
874 XBT_DEBUG("Staging var (instead of enabling) because min concurrency slack %i, with weight %f and concurrency"
876 minslack, weight, var->concurrency_share);
879 XBT_DEBUG("Enabling var with min concurrency slack %i", minslack);
881 } else if (disabling_var) {
882 // Are we disabling this variable?
885 var->sharing_weight = weight;
893 void System::update_constraint_bound(Constraint* cnst, double bound)
896 update_modified_set(cnst);
900 /** \brief Update the constraint set propagating recursively to other constraints so the system should not be entirely
903 * \param cnst the Constraint* affected by the change
905 * A recursive algorithm to optimize the system recalculation selecting only constraints that have changed. Each
906 * constraint change is propagated to the list of constraints for each variable.
908 void System::update_modified_set_rec(Constraint* cnst)
910 for (Element const& elem : cnst->enabled_element_set) {
911 Variable* var = elem.variable;
912 for (Element const& elem2 : var->cnsts) {
913 if (var->visited == visited_counter)
915 if (elem2.constraint != cnst && not elem2.constraint->modified_constraint_set_hook.is_linked()) {
916 modified_constraint_set.push_back(*elem2.constraint);
917 update_modified_set_rec(elem2.constraint);
920 // var will be ignored in later visits as long as sys->visited_counter does not move
921 var->visited = visited_counter;
925 void System::update_modified_set(Constraint* cnst)
927 /* nothing to do if selective update isn't active */
928 if (selective_update_active && not cnst->modified_constraint_set_hook.is_linked()) {
929 modified_constraint_set.push_back(*cnst);
930 update_modified_set_rec(cnst);
934 void System::remove_all_modified_set()
936 // We cleverly un-flag all variables just by incrementing visited_counter
937 // In effect, the var->visited value will no more be equal to visited counter
938 // To be clean, when visited counter has wrapped around, we force these var->visited values so that variables that
939 // were in the modified a long long time ago are not wrongly skipped here, which would lead to very nasty bugs
940 // (i.e. not readibily reproducible, and requiring a lot of run time before happening).
941 if (++visited_counter == 1) {
942 /* the counter wrapped around, reset each variable->visited */
943 for (Variable& var : variable_set)
946 modified_constraint_set.clear();
950 * Returns resource load (in flop per second, or byte per second, or similar)
952 * If the resource is shared (the default case), the load is sum of resource usage made by every variables located on
955 * If the resource is not shared (ie in FATPIPE mode), then the load is the max (not the sum) of all resource usages
956 * located on this resource.
958 double Constraint::get_usage() const
961 if (sharing_policy) {
962 for (Element const& elem : enabled_element_set)
963 if (elem.consumption_weight > 0)
964 result += elem.consumption_weight * elem.variable->value;
966 for (Element const& elem : enabled_element_set)
967 if (elem.consumption_weight > 0)
968 result = std::max(result, elem.consumption_weight * elem.variable->value);
973 int Constraint::get_variable_amount() const
975 return std::count_if(std::begin(enabled_element_set), std::end(enabled_element_set),
976 [](const Element& elem) { return elem.consumption_weight > 0; });