1 /* Copyright (c) 2004-2018. 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 System* make_new_maxmin_system(bool selective_update)
38 return new System(selective_update);
41 int Element::get_concurrency() const
43 // Ignore element with weight less than one (e.g. cross-traffic)
44 return (consumption_weight >= 1) ? 1 : 0;
45 // There are other alternatives, but they will change the behaviour of the model..
46 // So do not use it unless you want to make a new model.
47 // If you do, remember to change the variables concurrency share to reflect it.
48 // Potential examples are:
49 // return (elem->weight>0)?1:0;//Include element as soon as weight is non-zero
50 // return (int)ceil(elem->weight);//Include element as the rounded-up integer value of the element weight
53 void Element::decrease_concurrency()
55 xbt_assert(constraint->concurrency_current >= get_concurrency());
56 constraint->concurrency_current -= get_concurrency();
59 void Element::increase_concurrency()
61 constraint->concurrency_current += get_concurrency();
63 if (constraint->concurrency_current > constraint->concurrency_maximum)
64 constraint->concurrency_maximum = constraint->concurrency_current;
66 xbt_assert(constraint->get_concurrency_limit() < 0 ||
67 constraint->concurrency_current <= constraint->get_concurrency_limit(),
68 "Concurrency limit overflow!");
71 void System::check_concurrency() const
73 // These checks are very expensive, so do them only if we want to debug SURF LMM
74 if (not XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug))
77 for (Constraint const& cnst : constraint_set) {
79 for (Element const& elem : cnst.enabled_element_set) {
80 xbt_assert(elem.variable->sharing_weight > 0);
81 concurrency += elem.get_concurrency();
84 for (Element const& elem : cnst.disabled_element_set) {
85 // We should have staged variables only if concurrency is reached in some constraint
86 xbt_assert(cnst.get_concurrency_limit() < 0 || elem.variable->staged_weight == 0 ||
87 elem.variable->get_min_concurrency_slack() < elem.variable->concurrency_share,
88 "should not have staged variable!");
91 xbt_assert(cnst.get_concurrency_limit() < 0 || cnst.get_concurrency_limit() >= concurrency,
92 "concurrency check failed!");
93 xbt_assert(cnst.concurrency_current == concurrency, "concurrency_current is out-of-date!");
96 // Check that for each variable, all corresponding elements are in the same state (i.e. same element sets)
97 for (Variable const& var : variable_set) {
98 if (var.cnsts.empty())
101 const Element& elem = var.cnsts[0];
102 int belong_to_enabled = elem.enabled_element_set_hook.is_linked();
103 int belong_to_disabled = elem.disabled_element_set_hook.is_linked();
104 int belong_to_active = elem.active_element_set_hook.is_linked();
106 for (Element const& elem2 : var.cnsts) {
107 xbt_assert(belong_to_enabled == elem2.enabled_element_set_hook.is_linked(),
108 "Variable inconsistency (1): enabled_element_set");
109 xbt_assert(belong_to_disabled == elem2.disabled_element_set_hook.is_linked(),
110 "Variable inconsistency (2): disabled_element_set");
111 xbt_assert(belong_to_active == elem2.active_element_set_hook.is_linked(),
112 "Variable inconsistency (3): active_element_set");
117 void System::var_free(Variable* var)
119 XBT_IN("(sys=%p, var=%p)", this, var);
122 // TODOLATER Can do better than that by leaving only the variable in only one enabled_element_set, call
123 // update_modified_set, and then remove it..
124 if (not var->cnsts.empty())
125 update_modified_set(var->cnsts[0].constraint);
127 for (Element& elem : var->cnsts) {
128 if (var->sharing_weight > 0)
129 elem.decrease_concurrency();
130 if (elem.enabled_element_set_hook.is_linked())
131 simgrid::xbt::intrusive_erase(elem.constraint->enabled_element_set, elem);
132 if (elem.disabled_element_set_hook.is_linked())
133 simgrid::xbt::intrusive_erase(elem.constraint->disabled_element_set, elem);
134 if (elem.active_element_set_hook.is_linked())
135 simgrid::xbt::intrusive_erase(elem.constraint->active_element_set, elem);
136 int nelements = elem.constraint->enabled_element_set.size() + elem.constraint->disabled_element_set.size();
138 make_constraint_inactive(elem.constraint);
140 on_disabled_var(elem.constraint);
147 xbt_mallocator_release(variable_mallocator_, var);
151 System::System(bool selective_update) : selective_update_active(selective_update)
153 XBT_DEBUG("Setting selective_update_active flag to %d", selective_update_active);
155 if (selective_update)
156 modified_set_ = new kernel::resource::Action::ModifiedSet();
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_);
174 delete modified_set_;
177 void System::cnst_free(Constraint* cnst)
179 make_constraint_inactive(cnst);
183 Constraint::Constraint(void* id_value, double bound_value) : bound(bound_value), id(id_value)
185 id_int = Global_debug_id++;
189 concurrency_limit = sg_concurrency_limit;
190 concurrency_current = 0;
191 concurrency_maximum = 0;
192 sharing_policy = 1; /* FIXME: don't hardcode the value */
196 cnst_light = nullptr;
199 Constraint* System::constraint_new(void* id, double bound_value)
201 Constraint* cnst = new Constraint(id, bound_value);
202 insert_constraint(cnst);
206 void* System::variable_mallocator_new_f()
211 void System::variable_mallocator_free_f(void* var)
213 delete static_cast<Variable*>(var);
216 Variable* System::variable_new(simgrid::kernel::resource::Action* id, double sharing_weight, double bound,
217 int number_of_constraints)
219 XBT_IN("(sys=%p, id=%p, weight=%f, bound=%f, num_cons =%d)", this, id, sharing_weight, bound, number_of_constraints);
221 Variable* var = static_cast<Variable*>(xbt_mallocator_get(variable_mallocator_));
222 var->initialize(id, sharing_weight, bound, number_of_constraints, visited_counter_ - 1);
224 variable_set.push_front(*var);
226 variable_set.push_back(*var);
228 XBT_OUT(" returns %p", var);
232 void System::variable_free(Variable* var)
234 remove_variable(var);
238 void System::expand(Constraint* cnst, Variable* var, double consumption_weight)
242 // Check if this variable already has an active element in this constraint
243 // If it does, substract it from the required slack
244 int current_share = 0;
245 if (var->concurrency_share > 1) {
246 for (Element& elem : var->cnsts) {
247 if (elem.constraint == cnst && elem.enabled_element_set_hook.is_linked())
248 current_share += elem.get_concurrency();
252 // Check if we need to disable the variable
253 if (var->sharing_weight > 0 && var->concurrency_share - current_share > cnst->get_concurrency_slack()) {
254 double weight = var->sharing_weight;
256 for (Element const& elem : var->cnsts)
257 on_disabled_var(elem.constraint);
258 consumption_weight = 0;
259 var->staged_weight = weight;
260 xbt_assert(not var->sharing_weight);
263 xbt_assert(var->cnsts.size() < var->cnsts.capacity(), "Too much constraints");
265 var->cnsts.resize(var->cnsts.size() + 1);
266 Element& elem = var->cnsts.back();
268 elem.consumption_weight = consumption_weight;
269 elem.constraint = cnst;
272 if (var->sharing_weight) {
273 elem.constraint->enabled_element_set.push_front(elem);
274 elem.increase_concurrency();
276 elem.constraint->disabled_element_set.push_back(elem);
278 if (not selective_update_active) {
279 make_constraint_active(cnst);
280 } else if (elem.consumption_weight > 0 || var->sharing_weight > 0) {
281 make_constraint_active(cnst);
282 update_modified_set(cnst);
283 // TODOLATER: Why do we need this second call?
284 if (var->cnsts.size() > 1)
285 update_modified_set(var->cnsts[0].constraint);
291 void System::expand_add(Constraint* cnst, Variable* var, double value)
297 // BEWARE: In case you have multiple elements in one constraint, this will always add value to the first element.
299 std::find_if(begin(var->cnsts), end(var->cnsts), [&cnst](Element const& x) { return x.constraint == cnst; });
300 if (elem_it != end(var->cnsts)) {
301 Element& elem = *elem_it;
302 if (var->sharing_weight)
303 elem.decrease_concurrency();
305 if (cnst->sharing_policy)
306 elem.consumption_weight += value;
308 elem.consumption_weight = std::max(elem.consumption_weight, value);
310 // We need to check that increasing value of the element does not cross the concurrency limit
311 if (var->sharing_weight) {
312 if (cnst->get_concurrency_slack() < elem.get_concurrency()) {
313 double weight = var->sharing_weight;
315 for (Element const& elem2 : var->cnsts)
316 on_disabled_var(elem2.constraint);
317 var->staged_weight = weight;
318 xbt_assert(not var->sharing_weight);
320 elem.increase_concurrency();
322 update_modified_set(cnst);
324 expand(cnst, var, value);
329 Variable* Constraint::get_variable(const Element** elem) const
331 if (*elem == nullptr) {
332 // That is the first call, pick the first element among enabled_element_set (or disabled_element_set if
333 // enabled_element_set is empty)
334 if (not enabled_element_set.empty())
335 *elem = &enabled_element_set.front();
336 else if (not disabled_element_set.empty())
337 *elem = &disabled_element_set.front();
341 // elem is not null, so we carry on
342 if ((*elem)->enabled_element_set_hook.is_linked()) {
343 // Look at enabled_element_set, and jump to disabled_element_set when finished
344 auto iter = std::next(enabled_element_set.iterator_to(**elem));
345 if (iter != std::end(enabled_element_set))
347 else if (not disabled_element_set.empty())
348 *elem = &disabled_element_set.front();
352 auto iter = std::next(disabled_element_set.iterator_to(**elem));
353 *elem = iter != std::end(disabled_element_set) ? &*iter : nullptr;
357 return (*elem)->variable;
362 // if we modify the list between calls, normal version may loop forever
363 // this safe version ensures that we browse the list elements only once
364 Variable* Constraint::get_variable_safe(const Element** elem, const Element** nextelem, int* numelem) const
366 if (*elem == nullptr) {
367 *numelem = enabled_element_set.size() + disabled_element_set.size() - 1;
368 if (not enabled_element_set.empty())
369 *elem = &enabled_element_set.front();
370 else if (not disabled_element_set.empty())
371 *elem = &disabled_element_set.front();
382 // elem is not null, so we carry on
383 if ((*elem)->enabled_element_set_hook.is_linked()) {
384 // Look at enabled_element_set, and jump to disabled_element_set when finished
385 auto iter = std::next(enabled_element_set.iterator_to(**elem));
386 if (iter != std::end(enabled_element_set))
388 else if (not disabled_element_set.empty())
389 *nextelem = &disabled_element_set.front();
393 auto iter = std::next(disabled_element_set.iterator_to(**elem));
394 *nextelem = iter != std::end(disabled_element_set) ? &*iter : nullptr;
396 return (*elem)->variable;
401 static inline void saturated_constraints_update(double usage, int cnst_light_num, dyn_light_t& saturated_constraints,
404 xbt_assert(usage > 0, "Impossible");
406 if (*min_usage < 0 || *min_usage > usage) {
408 XBT_HERE(" min_usage=%f (cnst->remaining / cnst->usage =%f)", *min_usage, usage);
409 saturated_constraints.assign(1, cnst_light_num);
410 } else if (*min_usage == usage) {
411 saturated_constraints.emplace_back(cnst_light_num);
415 static inline void saturated_variable_set_update(ConstraintLight* cnst_light_tab,
416 const dyn_light_t& saturated_constraints, System* sys)
418 /* Add active variables (i.e. variables that need to be set) from the set of constraints to saturate
420 for (int const& saturated_cnst : saturated_constraints) {
421 ConstraintLight& cnst = cnst_light_tab[saturated_cnst];
422 for (Element const& elem : cnst.cnst->active_element_set) {
423 // Visiting active_element_set, so, by construction, should never get a zero weight, correct?
424 xbt_assert(elem.variable->sharing_weight > 0);
425 if (elem.consumption_weight > 0 && not elem.variable->saturated_variable_set_hook.is_linked())
426 sys->saturated_variable_set.push_back(*elem.variable);
431 template <class ElemList>
432 static void format_element_list(const ElemList& elem_list, int sharing_policy, double& sum, std::string& buf)
434 for (Element const& elem : elem_list) {
435 buf += std::to_string(elem.consumption_weight) + ".'" + std::to_string(elem.variable->id_int) + "'(" +
436 std::to_string(elem.variable->value) + ")" + (sharing_policy ? " + " : " , ");
438 sum += elem.consumption_weight * elem.variable->value;
440 sum = std::max(sum, elem.consumption_weight * elem.variable->value);
444 void System::print() const
446 std::string buf = std::string("MAX-MIN ( ");
448 /* Printing Objective */
449 for (Variable const& var : variable_set)
450 buf += "'" + std::to_string(var.id_int) + "'(" + std::to_string(var.sharing_weight) + ") ";
452 XBT_DEBUG("%20s", buf.c_str());
455 XBT_DEBUG("Constraints");
456 /* Printing Constraints */
457 for (Constraint const& cnst : active_constraint_set) {
459 // Show the enabled variables
461 buf += cnst.sharing_policy ? "(" : "max(";
462 format_element_list(cnst.enabled_element_set, cnst.sharing_policy, sum, buf);
463 // TODO: Adding disabled elements only for test compatibility, but do we really want them to be printed?
464 format_element_list(cnst.disabled_element_set, cnst.sharing_policy, sum, buf);
466 buf += "0) <= " + std::to_string(cnst.bound) + " ('" + std::to_string(cnst.id_int) + "')";
468 if (not cnst.sharing_policy) {
469 buf += " [MAX-Constraint]";
471 XBT_DEBUG("%s", buf.c_str());
473 xbt_assert(not double_positive(sum - cnst.bound, cnst.bound * sg_maxmin_precision),
474 "Incorrect value (%f is not smaller than %f): %g", sum, cnst.bound, sum - cnst.bound);
477 XBT_DEBUG("Variables");
478 /* Printing Result */
479 for (Variable const& var : variable_set) {
481 XBT_DEBUG("'%d'(%f) : %f (<=%f)", var.id_int, var.sharing_weight, var.value, var.bound);
482 xbt_assert(not double_positive(var.value - var.bound, var.bound * sg_maxmin_precision),
483 "Incorrect value (%f is not smaller than %f", var.value, var.bound);
485 XBT_DEBUG("'%d'(%f) : %f", var.id_int, var.sharing_weight, var.value);
490 void System::lmm_solve()
493 XBT_IN("(sys=%p)", this);
494 /* Compute Usage and store the variables that reach the maximum. If selective_update_active is true, only
495 * constraints that changed are considered. Otherwise all constraints with active actions are considered.
497 if (selective_update_active)
498 lmm_solve(modified_constraint_set);
500 lmm_solve(active_constraint_set);
505 template <class CnstList> void System::lmm_solve(CnstList& cnst_list)
507 double min_usage = -1;
508 double min_bound = -1;
510 XBT_DEBUG("Active constraints : %zu", cnst_list.size());
511 /* Init: Only modified code portions: reset the value of active variables */
512 for (Constraint const& cnst : cnst_list) {
513 for (Element const& elem : cnst.enabled_element_set) {
514 xbt_assert(elem.variable->sharing_weight > 0.0);
515 elem.variable->value = 0.0;
519 ConstraintLight* cnst_light_tab = new ConstraintLight[cnst_list.size()]();
520 int cnst_light_num = 0;
521 dyn_light_t saturated_constraints;
523 for (Constraint& cnst : cnst_list) {
524 /* INIT: Collect constraints that actually need to be saturated (i.e remaining and usage are strictly positive)
525 * into cnst_light_tab. */
526 cnst.remaining = cnst.bound;
527 if (not double_positive(cnst.remaining, cnst.bound * sg_maxmin_precision))
530 for (Element& elem : cnst.enabled_element_set) {
531 xbt_assert(elem.variable->sharing_weight > 0);
532 if (elem.consumption_weight > 0) {
533 if (cnst.sharing_policy)
534 cnst.usage += elem.consumption_weight / elem.variable->sharing_weight;
535 else if (cnst.usage < elem.consumption_weight / elem.variable->sharing_weight)
536 cnst.usage = elem.consumption_weight / elem.variable->sharing_weight;
539 simgrid::kernel::resource::Action* action = static_cast<simgrid::kernel::resource::Action*>(elem.variable->id);
540 if (modified_set_ && not action->is_within_modified_set())
541 modified_set_->push_back(*action);
544 XBT_DEBUG("Constraint '%d' usage: %f remaining: %f concurrency: %i<=%i<=%i", cnst.id_int, cnst.usage,
545 cnst.remaining, cnst.concurrency_current, cnst.concurrency_maximum, cnst.get_concurrency_limit());
546 /* Saturated constraints update */
548 if (cnst.usage > 0) {
549 cnst_light_tab[cnst_light_num].cnst = &cnst;
550 cnst.cnst_light = &cnst_light_tab[cnst_light_num];
551 cnst_light_tab[cnst_light_num].remaining_over_usage = cnst.remaining / cnst.usage;
552 saturated_constraints_update(cnst_light_tab[cnst_light_num].remaining_over_usage, cnst_light_num,
553 saturated_constraints, &min_usage);
554 xbt_assert(not cnst.active_element_set.empty(),
555 "There is no sense adding a constraint that has no active element!");
560 saturated_variable_set_update(cnst_light_tab, saturated_constraints, this);
562 /* Saturated variables update */
564 /* Fix the variables that have to be */
565 auto& var_list = saturated_variable_set;
566 for (Variable const& var : var_list) {
567 if (var.sharing_weight <= 0.0)
569 /* First check if some of these variables could reach their upper bound and update min_bound accordingly. */
570 XBT_DEBUG("var=%d, var.bound=%f, var.weight=%f, min_usage=%f, var.bound*var.weight=%f", var.id_int, var.bound,
571 var.sharing_weight, min_usage, var.bound * var.sharing_weight);
572 if ((var.bound > 0) && (var.bound * var.sharing_weight < min_usage)) {
574 min_bound = var.bound * var.sharing_weight;
576 min_bound = std::min(min_bound, (var.bound * var.sharing_weight));
577 XBT_DEBUG("Updated min_bound=%f", min_bound);
581 while (not var_list.empty()) {
582 Variable& var = var_list.front();
584 // If no variable could reach its bound, deal iteratively the constraints usage ( at worst one constraint is
585 // saturated at each cycle)
586 var.value = min_usage / var.sharing_weight;
587 XBT_DEBUG("Setting var (%d) value to %f\n", var.id_int, var.value);
589 // If there exist a variable that can reach its bound, only update it (and other with the same bound) for now.
590 if (double_equals(min_bound, var.bound * var.sharing_weight, sg_maxmin_precision)) {
591 var.value = var.bound;
592 XBT_DEBUG("Setting %p (%d) value to %f\n", &var, var.id_int, var.value);
594 // Variables which bound is different are not considered for this cycle, but they will be afterwards.
595 XBT_DEBUG("Do not consider %p (%d) \n", &var, var.id_int);
596 var_list.pop_front();
600 XBT_DEBUG("Min usage: %f, Var(%d).weight: %f, Var(%d).value: %f ", min_usage, var.id_int, var.sharing_weight,
601 var.id_int, var.value);
603 /* Update the usage of contraints where this variable is involved */
604 for (Element& elem : var.cnsts) {
605 Constraint* cnst = elem.constraint;
606 if (cnst->sharing_policy) {
607 // Remember: shared constraints require that sum(elem.value * var.value) < cnst->bound
608 double_update(&(cnst->remaining), elem.consumption_weight * var.value, cnst->bound * sg_maxmin_precision);
609 double_update(&(cnst->usage), elem.consumption_weight / var.sharing_weight, sg_maxmin_precision);
610 // If the constraint is saturated, remove it from the set of active constraints (light_tab)
611 if (not double_positive(cnst->usage, sg_maxmin_precision) ||
612 not double_positive(cnst->remaining, cnst->bound * sg_maxmin_precision)) {
613 if (cnst->cnst_light) {
614 int index = (cnst->cnst_light - cnst_light_tab);
615 XBT_DEBUG("index: %d \t cnst_light_num: %d \t || usage: %f remaining: %f bound: %f ", index,
616 cnst_light_num, cnst->usage, cnst->remaining, cnst->bound);
617 cnst_light_tab[index] = cnst_light_tab[cnst_light_num - 1];
618 cnst_light_tab[index].cnst->cnst_light = &cnst_light_tab[index];
620 cnst->cnst_light = nullptr;
623 cnst->cnst_light->remaining_over_usage = cnst->remaining / cnst->usage;
625 elem.make_inactive();
627 // Remember: non-shared constraints only require that max(elem.value * var.value) < cnst->bound
629 elem.make_inactive();
630 for (Element& elem2 : cnst->enabled_element_set) {
631 xbt_assert(elem2.variable->sharing_weight > 0);
632 if (elem2.variable->value > 0)
634 if (elem2.consumption_weight > 0)
635 cnst->usage = std::max(cnst->usage, elem2.consumption_weight / elem2.variable->sharing_weight);
637 // If the constraint is saturated, remove it from the set of active constraints (light_tab)
638 if (not double_positive(cnst->usage, sg_maxmin_precision) ||
639 not double_positive(cnst->remaining, cnst->bound * sg_maxmin_precision)) {
640 if (cnst->cnst_light) {
641 int index = (cnst->cnst_light - cnst_light_tab);
642 XBT_DEBUG("index: %d \t cnst_light_num: %d \t || \t cnst: %p \t cnst->cnst_light: %p "
643 "\t cnst_light_tab: %p usage: %f remaining: %f bound: %f ",
644 index, cnst_light_num, cnst, cnst->cnst_light, cnst_light_tab, cnst->usage, cnst->remaining,
646 cnst_light_tab[index] = cnst_light_tab[cnst_light_num - 1];
647 cnst_light_tab[index].cnst->cnst_light = &cnst_light_tab[index];
649 cnst->cnst_light = nullptr;
652 cnst->cnst_light->remaining_over_usage = cnst->remaining / cnst->usage;
653 xbt_assert(not cnst->active_element_set.empty(),
654 "Should not keep a maximum constraint that has no active"
655 " element! You want to check the maxmin precision and possible rounding effects.");
659 var_list.pop_front();
662 /* Find out which variables reach the maximum */
665 saturated_constraints.clear();
667 for (pos = 0; pos < cnst_light_num; pos++) {
668 xbt_assert(not cnst_light_tab[pos].cnst->active_element_set.empty(),
669 "Cannot saturate more a constraint that has"
670 " no active element! You may want to change the maxmin precision (--cfg=maxmin/precision:<new_value>)"
671 " because of possible rounding effects.\n\tFor the record, the usage of this constraint is %g while "
672 "the maxmin precision to which it is compared is %g.\n\tThe usage of the previous constraint is %g.",
673 cnst_light_tab[pos].cnst->usage, sg_maxmin_precision, cnst_light_tab[pos - 1].cnst->usage);
674 saturated_constraints_update(cnst_light_tab[pos].remaining_over_usage, pos, saturated_constraints, &min_usage);
677 saturated_variable_set_update(cnst_light_tab, saturated_constraints, this);
679 } while (cnst_light_num > 0);
682 if (selective_update_active)
683 remove_all_modified_set();
685 if (XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug)) {
691 delete[] cnst_light_tab;
694 /** \brief Attribute the value bound to var->bound.
696 * \param var the Variable*
697 * \param bound the new bound to associate with var
699 * Makes var->bound equal to bound. Whenever this function is called a change is signed in the system. To
700 * avoid false system changing detection it is a good idea to test (bound != 0) before calling it.
702 void System::update_variable_bound(Variable* var, double bound)
707 if (not var->cnsts.empty())
708 update_modified_set(var->cnsts[0].constraint);
711 void Variable::initialize(simgrid::kernel::resource::Action* id_value, double sharing_weight_value, double bound_value,
712 int number_of_constraints, unsigned visited_value)
715 id_int = Global_debug_id++;
716 cnsts.reserve(number_of_constraints);
717 sharing_weight = sharing_weight_value;
720 concurrency_share = 1;
722 visited = visited_value;
726 xbt_assert(not variable_set_hook.is_linked());
727 xbt_assert(not saturated_variable_set_hook.is_linked());
730 int Variable::get_min_concurrency_slack() const
732 int minslack = std::numeric_limits<int>::max();
733 for (Element const& elem : cnsts) {
734 int slack = elem.constraint->get_concurrency_slack();
735 if (slack < minslack) {
736 // This is only an optimization, to avoid looking at more constraints when slack is already zero
745 // Small remark: In this implementation of System::enable_var() and System::disable_var(), we will meet multiple times
746 // with var when running System::update_modified_set().
747 // A priori not a big performance issue, but we might do better by calling System::update_modified_set() within the for
748 // loops (after doing the first for enabling==1, and before doing the last for disabling==1)
749 void System::enable_var(Variable* var)
751 xbt_assert(not XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug) || var->can_enable());
753 var->sharing_weight = var->staged_weight;
754 var->staged_weight = 0;
756 // Enabling the variable, move var to list head. Subtlety is: here, we need to call update_modified_set AFTER
757 // moving at least one element of var.
759 simgrid::xbt::intrusive_erase(variable_set, *var);
760 variable_set.push_front(*var);
761 for (Element& elem : var->cnsts) {
762 simgrid::xbt::intrusive_erase(elem.constraint->disabled_element_set, elem);
763 elem.constraint->enabled_element_set.push_front(elem);
764 elem.increase_concurrency();
766 if (not var->cnsts.empty())
767 update_modified_set(var->cnsts[0].constraint);
769 // When used within on_disabled_var, we would get an assertion fail, because transiently there can be variables
770 // that are staged and could be activated.
771 // Anyway, caller functions all call check_concurrency() in the end.
774 void System::disable_var(Variable* var)
776 xbt_assert(not var->staged_weight, "Staged weight should have been cleared");
777 // Disabling the variable, move to var to list tail. Subtlety is: here, we need to call update_modified_set
778 // BEFORE moving the last element of var.
779 simgrid::xbt::intrusive_erase(variable_set, *var);
780 variable_set.push_back(*var);
781 if (not var->cnsts.empty())
782 update_modified_set(var->cnsts[0].constraint);
783 for (Element& elem : var->cnsts) {
784 simgrid::xbt::intrusive_erase(elem.constraint->enabled_element_set, elem);
785 elem.constraint->disabled_element_set.push_back(elem);
786 if (elem.active_element_set_hook.is_linked())
787 simgrid::xbt::intrusive_erase(elem.constraint->active_element_set, elem);
788 elem.decrease_concurrency();
791 var->sharing_weight = 0.0;
792 var->staged_weight = 0.0;
797 /* /brief Find variables that can be enabled and enable them.
799 * Assuming that the variable has already been removed from non-zero weights
800 * Can we find a staged variable to add?
801 * If yes, check that none of the constraints that this variable is involved in is at the limit of its concurrency
802 * And then add it to enabled variables
804 void System::on_disabled_var(Constraint* cnstr)
806 if (cnstr->get_concurrency_limit() < 0)
809 int numelem = cnstr->disabled_element_set.size();
813 Element* elem = &cnstr->disabled_element_set.front();
815 // Cannot use foreach loop, because System::enable_var() will modify disabled_element_set.. within the loop
816 while (numelem-- && elem) {
819 if (elem->disabled_element_set_hook.is_linked()) {
820 auto iter = std::next(cnstr->disabled_element_set.iterator_to(*elem));
821 nextelem = iter != std::end(cnstr->disabled_element_set) ? &*iter : nullptr;
826 if (elem->variable->staged_weight > 0 && elem->variable->can_enable()) {
827 // Found a staged variable
828 // TODOLATER: Add random timing function to model reservation protocol fuzziness? Then how to make sure that
829 // staged variables will eventually be called?
830 enable_var(elem->variable);
833 xbt_assert(cnstr->concurrency_current <= cnstr->get_concurrency_limit(), "Concurrency overflow!");
834 if (cnstr->concurrency_current == cnstr->get_concurrency_limit())
840 // We could get an assertion fail, because transiently there can be variables that are staged and could be activated.
841 // And we need to go through all constraints of the disabled var before getting back a coherent state.
842 // Anyway, caller functions all call check_concurrency() in the end.
845 /* \brief update the weight of a variable, and enable/disable it.
846 * @return Returns whether a change was made
848 void System::update_variable_weight(Variable* var, double weight)
850 xbt_assert(weight >= 0, "Variable weight should not be negative!");
852 if (weight == var->sharing_weight)
855 int enabling_var = (weight > 0 && var->sharing_weight <= 0);
856 int disabling_var = (weight <= 0 && var->sharing_weight > 0);
858 XBT_IN("(sys=%p, var=%p, weight=%f)", this, var, weight);
862 // Are we enabling this variable?
864 var->staged_weight = weight;
865 int minslack = var->get_min_concurrency_slack();
866 if (minslack < var->concurrency_share) {
867 XBT_DEBUG("Staging var (instead of enabling) because min concurrency slack %i, with weight %f and concurrency"
869 minslack, weight, var->concurrency_share);
872 XBT_DEBUG("Enabling var with min concurrency slack %i", minslack);
874 } else if (disabling_var) {
875 // Are we disabling this variable?
878 var->sharing_weight = weight;
886 void System::update_constraint_bound(Constraint* cnst, double bound)
889 update_modified_set(cnst);
893 /** \brief Update the constraint set propagating recursively to other constraints so the system should not be entirely
896 * \param cnst the Constraint* affected by the change
898 * A recursive algorithm to optimize the system recalculation selecting only constraints that have changed. Each
899 * constraint change is propagated to the list of constraints for each variable.
901 void System::update_modified_set_rec(Constraint* cnst)
903 for (Element const& elem : cnst->enabled_element_set) {
904 Variable* var = elem.variable;
905 for (Element const& elem2 : var->cnsts) {
906 if (var->visited == visited_counter_)
908 if (elem2.constraint != cnst && not elem2.constraint->modified_constraint_set_hook.is_linked()) {
909 modified_constraint_set.push_back(*elem2.constraint);
910 update_modified_set_rec(elem2.constraint);
913 // var will be ignored in later visits as long as sys->visited_counter does not move
914 var->visited = visited_counter_;
918 void System::update_modified_set(Constraint* cnst)
920 /* nothing to do if selective update isn't active */
921 if (selective_update_active && not cnst->modified_constraint_set_hook.is_linked()) {
922 modified_constraint_set.push_back(*cnst);
923 update_modified_set_rec(cnst);
927 void System::remove_all_modified_set()
929 // We cleverly un-flag all variables just by incrementing visited_counter
930 // In effect, the var->visited value will no more be equal to visited counter
931 // To be clean, when visited counter has wrapped around, we force these var->visited values so that variables that
932 // were in the modified a long long time ago are not wrongly skipped here, which would lead to very nasty bugs
933 // (i.e. not readibily reproducible, and requiring a lot of run time before happening).
934 if (++visited_counter_ == 1) {
935 /* the counter wrapped around, reset each variable->visited */
936 for (Variable& var : variable_set)
939 modified_constraint_set.clear();
943 * Returns resource load (in flop per second, or byte per second, or similar)
945 * If the resource is shared (the default case), the load is sum of resource usage made by every variables located on
948 * If the resource is not shared (ie in FATPIPE mode), then the load is the max (not the sum) of all resource usages
949 * located on this resource.
951 double Constraint::get_usage() const
954 if (sharing_policy) {
955 for (Element const& elem : enabled_element_set)
956 if (elem.consumption_weight > 0)
957 result += elem.consumption_weight * elem.variable->value;
959 for (Element const& elem : enabled_element_set)
960 if (elem.consumption_weight > 0)
961 result = std::max(result, elem.consumption_weight * elem.variable->value);
966 int Constraint::get_variable_amount() const
968 return std::count_if(std::begin(enabled_element_set), std::end(enabled_element_set),
969 [](const Element& elem) { return elem.consumption_weight > 0; });