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"
20 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(surf_maxmin, surf, "Logging specific to SURF (maxmin)");
22 double sg_maxmin_precision = 0.00001; /* Change this with --cfg=maxmin/precision:VALUE */
23 double sg_surf_precision = 0.00001; /* Change this with --cfg=surf/precision:VALUE */
24 int sg_concurrency_limit = -1; /* Change this with --cfg=maxmin/concurrency-limit:VALUE */
30 typedef std::vector<int> dyn_light_t;
32 int s_lmm_variable_t::Global_debug_id = 1;
33 int s_lmm_constraint_t::Global_debug_id = 1;
35 int s_lmm_element_t::get_concurrency() const
37 // Ignore element with weight less than one (e.g. cross-traffic)
38 return (consumption_weight >= 1) ? 1 : 0;
39 // There are other alternatives, but they will change the behaviour of the model..
40 // So do not use it unless you want to make a new model.
41 // If you do, remember to change the variables concurrency share to reflect it.
42 // Potential examples are:
43 // return (elem->weight>0)?1:0;//Include element as soon as weight is non-zero
44 // return (int)ceil(elem->weight);//Include element as the rounded-up integer value of the element weight
47 void s_lmm_element_t::decrease_concurrency()
49 xbt_assert(constraint->concurrency_current >= get_concurrency());
50 constraint->concurrency_current -= get_concurrency();
53 void s_lmm_element_t::increase_concurrency()
55 constraint->concurrency_current += get_concurrency();
57 if (constraint->concurrency_current > constraint->concurrency_maximum)
58 constraint->concurrency_maximum = constraint->concurrency_current;
60 xbt_assert(constraint->get_concurrency_limit() < 0 ||
61 constraint->concurrency_current <= constraint->get_concurrency_limit(),
62 "Concurrency limit overflow!");
65 void s_lmm_system_t::check_concurrency()
67 // These checks are very expensive, so do them only if we want to debug SURF LMM
68 if (not XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug))
72 xbt_swag_foreach(cnstIt, &constraint_set)
74 lmm_constraint_t cnst = (lmm_constraint_t)cnstIt;
77 xbt_swag_foreach(elemIt, &(cnst->enabled_element_set))
79 lmm_element_t elem = (lmm_element_t)elemIt;
80 xbt_assert(elem->variable->sharing_weight > 0);
81 concurrency += elem->get_concurrency();
84 xbt_swag_foreach(elemIt, &(cnst->disabled_element_set))
86 lmm_element_t elem = (lmm_element_t)elemIt;
87 // We should have staged variables only if concurrency is reached in some constraint
88 xbt_assert(cnst->get_concurrency_limit() < 0 || elem->variable->staged_weight == 0 ||
89 elem->variable->get_min_concurrency_slack() < elem->variable->concurrency_share,
90 "should not have staged variable!");
93 xbt_assert(cnst->get_concurrency_limit() < 0 || cnst->get_concurrency_limit() >= concurrency,
94 "concurrency check failed!");
95 xbt_assert(cnst->concurrency_current == concurrency, "concurrency_current is out-of-date!");
98 // Check that for each variable, all corresponding elements are in the same state (i.e. same element sets)
100 xbt_swag_foreach(varIt, &variable_set)
102 lmm_variable_t var = (lmm_variable_t)varIt;
104 if (var->cnsts.empty())
107 lmm_element_t elem = &var->cnsts[0];
108 int belong_to_enabled = xbt_swag_belongs(elem, &(elem->constraint->enabled_element_set));
109 int belong_to_disabled = xbt_swag_belongs(elem, &(elem->constraint->disabled_element_set));
110 int belong_to_active = xbt_swag_belongs(elem, &(elem->constraint->active_element_set));
112 for (s_lmm_element_t const& elem : var->cnsts) {
113 xbt_assert(belong_to_enabled == xbt_swag_belongs(&elem, &(elem.constraint->enabled_element_set)),
114 "Variable inconsistency (1): enabled_element_set");
115 xbt_assert(belong_to_disabled == xbt_swag_belongs(&elem, &(elem.constraint->disabled_element_set)),
116 "Variable inconsistency (2): disabled_element_set");
117 xbt_assert(belong_to_active == xbt_swag_belongs(&elem, &(elem.constraint->active_element_set)),
118 "Variable inconsistency (3): active_element_set");
123 void s_lmm_system_t::var_free(lmm_variable_t var)
125 XBT_IN("(sys=%p, var=%p)", this, var);
128 // TODOLATER Can do better than that by leaving only the variable in only one enabled_element_set, call
129 // update_modified_set, and then remove it..
130 if (not var->cnsts.empty())
131 update_modified_set(var->cnsts[0].constraint);
133 for (s_lmm_element_t& elem : var->cnsts) {
134 if (var->sharing_weight > 0)
135 elem.decrease_concurrency();
136 xbt_swag_remove(&elem, &(elem.constraint->enabled_element_set));
137 xbt_swag_remove(&elem, &(elem.constraint->disabled_element_set));
138 xbt_swag_remove(&elem, &(elem.constraint->active_element_set));
139 int nelements = xbt_swag_size(&(elem.constraint->enabled_element_set)) +
140 xbt_swag_size(&(elem.constraint->disabled_element_set));
142 make_constraint_inactive(elem.constraint);
144 on_disabled_var(elem.constraint);
151 xbt_mallocator_release(variable_mallocator, var);
155 s_lmm_system_t::s_lmm_system_t(bool selective_update) : selective_update_active(selective_update)
157 s_lmm_variable_t var;
158 s_lmm_constraint_t cnst;
163 XBT_DEBUG("Setting selective_update_active flag to %d", selective_update_active);
165 xbt_swag_init(&variable_set, xbt_swag_offset(var, variable_set_hookup));
166 xbt_swag_init(&constraint_set, xbt_swag_offset(cnst, constraint_set_hookup));
168 xbt_swag_init(&active_constraint_set, xbt_swag_offset(cnst, active_constraint_set_hookup));
170 xbt_swag_init(&modified_constraint_set, xbt_swag_offset(cnst, modified_constraint_set_hookup));
171 xbt_swag_init(&saturated_variable_set, xbt_swag_offset(var, saturated_variable_set_hookup));
172 xbt_swag_init(&saturated_constraint_set, xbt_swag_offset(cnst, saturated_constraint_set_hookup));
174 keep_track = nullptr;
175 variable_mallocator = xbt_mallocator_new(65536, s_lmm_system_t::variable_mallocator_new_f,
176 s_lmm_system_t::variable_mallocator_free_f, nullptr);
177 solve_fun = &lmm_solve;
180 s_lmm_system_t::~s_lmm_system_t()
183 lmm_constraint_t cnst;
185 while ((var = extract_variable())) {
186 auto demangled = simgrid::xbt::demangle(typeid(*var->id).name());
187 XBT_WARN("Probable bug: a %s variable (#%d) not removed before the LMM system destruction.", demangled.get(),
191 while ((cnst = extract_constraint()))
194 xbt_mallocator_free(variable_mallocator);
197 void s_lmm_system_t::cnst_free(lmm_constraint_t cnst)
199 make_constraint_inactive(cnst);
203 s_lmm_constraint_t::s_lmm_constraint_t(void* id_value, double bound_value) : bound(bound_value), id(id_value)
205 s_lmm_element_t elem;
207 id_int = Global_debug_id++;
208 xbt_swag_init(&enabled_element_set, xbt_swag_offset(elem, enabled_element_set_hookup));
209 xbt_swag_init(&disabled_element_set, xbt_swag_offset(elem, disabled_element_set_hookup));
210 xbt_swag_init(&active_element_set, xbt_swag_offset(elem, active_element_set_hookup));
214 concurrency_limit = sg_concurrency_limit;
215 concurrency_current = 0;
216 concurrency_maximum = 0;
217 sharing_policy = 1; /* FIXME: don't hardcode the value */
221 cnst_light = nullptr;
224 lmm_constraint_t s_lmm_system_t::constraint_new(void* id, double bound_value)
226 lmm_constraint_t cnst = new s_lmm_constraint_t(id, bound_value);
227 insert_constraint(cnst);
231 void* s_lmm_system_t::variable_mallocator_new_f()
233 return new s_lmm_variable_t;
236 void s_lmm_system_t::variable_mallocator_free_f(void* var)
238 delete static_cast<lmm_variable_t>(var);
241 lmm_variable_t s_lmm_system_t::variable_new(simgrid::surf::Action* id, double sharing_weight, double bound,
242 int number_of_constraints)
244 XBT_IN("(sys=%p, id=%p, weight=%f, bound=%f, num_cons =%d)", this, id, sharing_weight, bound, number_of_constraints);
246 lmm_variable_t var = static_cast<lmm_variable_t>(xbt_mallocator_get(variable_mallocator));
247 var->initialize(id, sharing_weight, bound, number_of_constraints, visited_counter - 1);
249 xbt_swag_insert_at_head(var, &variable_set);
251 xbt_swag_insert_at_tail(var, &variable_set);
253 XBT_OUT(" returns %p", var);
257 void s_lmm_system_t::variable_free(lmm_variable_t var)
259 remove_variable(var);
263 void s_lmm_system_t::expand(lmm_constraint_t cnst, lmm_variable_t var, double consumption_weight)
267 // Check if this variable already has an active element in this constraint
268 // If it does, substract it from the required slack
269 int current_share = 0;
270 if (var->concurrency_share > 1) {
271 for (s_lmm_element_t& elem : var->cnsts) {
272 if (elem.constraint == cnst && xbt_swag_belongs(&elem, &(elem.constraint->enabled_element_set)))
273 current_share += elem.get_concurrency();
277 // Check if we need to disable the variable
278 if (var->sharing_weight > 0 && var->concurrency_share - current_share > cnst->get_concurrency_slack()) {
279 double weight = var->sharing_weight;
281 for (s_lmm_element_t const& elem : var->cnsts)
282 on_disabled_var(elem.constraint);
283 consumption_weight = 0;
284 var->staged_weight = weight;
285 xbt_assert(not var->sharing_weight);
288 xbt_assert(var->cnsts.size() < var->cnsts.capacity(), "Too much constraints");
290 var->cnsts.resize(var->cnsts.size() + 1);
291 s_lmm_element_t& elem = var->cnsts.back();
293 elem.consumption_weight = consumption_weight;
294 elem.constraint = cnst;
297 if (var->sharing_weight) {
298 xbt_swag_insert_at_head(&elem, &(elem.constraint->enabled_element_set));
299 elem.increase_concurrency();
301 xbt_swag_insert_at_tail(&elem, &(elem.constraint->disabled_element_set));
303 if (not selective_update_active) {
304 make_constraint_active(cnst);
305 } else if (elem.consumption_weight > 0 || var->sharing_weight > 0) {
306 make_constraint_active(cnst);
307 update_modified_set(cnst);
308 // TODOLATER: Why do we need this second call?
309 if (var->cnsts.size() > 1)
310 update_modified_set(var->cnsts[0].constraint);
316 void s_lmm_system_t::expand_add(lmm_constraint_t cnst, lmm_variable_t var, double value)
322 // BEWARE: In case you have multiple elements in one constraint, this will always add value to the first element.
323 auto elem_it = std::find_if(begin(var->cnsts), end(var->cnsts),
324 [&cnst](s_lmm_element_t const& x) { return x.constraint == cnst; });
325 if (elem_it != end(var->cnsts)) {
326 s_lmm_element_t& elem = *elem_it;
327 if (var->sharing_weight)
328 elem.decrease_concurrency();
330 if (cnst->sharing_policy)
331 elem.consumption_weight += value;
333 elem.consumption_weight = std::max(elem.consumption_weight, value);
335 // We need to check that increasing value of the element does not cross the concurrency limit
336 if (var->sharing_weight) {
337 if (cnst->get_concurrency_slack() < elem.get_concurrency()) {
338 double weight = var->sharing_weight;
340 for (s_lmm_element_t const& elem2 : var->cnsts)
341 on_disabled_var(elem2.constraint);
342 var->staged_weight = weight;
343 xbt_assert(not var->sharing_weight);
345 elem.increase_concurrency();
347 update_modified_set(cnst);
349 expand(cnst, var, value);
354 lmm_variable_t s_lmm_constraint_t::get_variable(lmm_element_t* elem) const
356 if (*elem == nullptr) {
357 // That is the first call, pick the first element among enabled_element_set (or disabled_element_set if
358 // enabled_element_set is empty)
359 *elem = (lmm_element_t)xbt_swag_getFirst(&enabled_element_set);
360 if (*elem == nullptr)
361 *elem = (lmm_element_t)xbt_swag_getFirst(&disabled_element_set);
363 // elem is not null, so we carry on
364 if (xbt_swag_belongs(*elem, &enabled_element_set)) {
365 // Look at enabled_element_set, and jump to disabled_element_set when finished
366 *elem = (lmm_element_t)xbt_swag_getNext(*elem, enabled_element_set.offset);
367 if (*elem == nullptr)
368 *elem = (lmm_element_t)xbt_swag_getFirst(&disabled_element_set);
370 *elem = (lmm_element_t)xbt_swag_getNext(*elem, disabled_element_set.offset);
374 return (*elem)->variable;
379 // if we modify the swag between calls, normal version may loop forever
380 // this safe version ensures that we browse the swag elements only once
381 lmm_variable_t s_lmm_constraint_t::get_variable_safe(lmm_element_t* elem, lmm_element_t* nextelem, int* numelem) const
383 if (*elem == nullptr) {
384 *elem = (lmm_element_t)xbt_swag_getFirst(&enabled_element_set);
385 *numelem = xbt_swag_size(&enabled_element_set) + xbt_swag_size(&disabled_element_set) - 1;
386 if (*elem == nullptr)
387 *elem = (lmm_element_t)xbt_swag_getFirst(&disabled_element_set);
396 // elem is not null, so we carry on
397 if (xbt_swag_belongs(*elem, &enabled_element_set)) {
398 // Look at enabled_element_set, and jump to disabled_element_set when finished
399 *nextelem = (lmm_element_t)xbt_swag_getNext(*elem, enabled_element_set.offset);
400 if (*nextelem == nullptr)
401 *nextelem = (lmm_element_t)xbt_swag_getFirst(&disabled_element_set);
403 *nextelem = (lmm_element_t)xbt_swag_getNext(*elem, disabled_element_set.offset);
405 return (*elem)->variable;
410 static inline void saturated_constraints_update(double usage, int cnst_light_num, dyn_light_t& saturated_constraints,
413 xbt_assert(usage > 0, "Impossible");
415 if (*min_usage < 0 || *min_usage > usage) {
417 XBT_HERE(" min_usage=%f (cnst->remaining / cnst->usage =%f)", *min_usage, usage);
418 saturated_constraints.assign(1, cnst_light_num);
419 } else if (*min_usage == usage) {
420 saturated_constraints.emplace_back(cnst_light_num);
424 static inline void saturated_variable_set_update(s_lmm_constraint_light_t* cnst_light_tab,
425 const dyn_light_t& saturated_constraints, lmm_system_t sys)
427 /* Add active variables (i.e. variables that need to be set) from the set of constraints to saturate
429 for (int const& saturated_cnst : saturated_constraints) {
430 lmm_constraint_light_t cnst = &cnst_light_tab[saturated_cnst];
432 xbt_swag_t elem_list = &(cnst->cnst->active_element_set);
433 xbt_swag_foreach(_elem, elem_list)
435 lmm_element_t elem = (lmm_element_t)_elem;
436 // Visiting active_element_set, so, by construction, should never get a zero weight, correct?
437 xbt_assert(elem->variable->sharing_weight > 0);
438 if (elem->consumption_weight > 0)
439 xbt_swag_insert(elem->variable, &(sys->saturated_variable_set));
444 static void format_lmm_element_swag(xbt_swag_t elem_list, int sharing_policy, double& sum, std::string& buf)
447 xbt_swag_foreach(_elem, elem_list)
449 lmm_element_t elem = (lmm_element_t)_elem;
450 buf += std::to_string(elem->consumption_weight) + ".'" + std::to_string(elem->variable->id_int) + "'(" +
451 std::to_string(elem->variable->value) + ")" + (sharing_policy ? " + " : " , ");
453 sum += elem->consumption_weight * elem->variable->value;
455 sum = std::max(sum, elem->consumption_weight * elem->variable->value);
459 void s_lmm_system_t::print()
461 std::string buf = std::string("MAX-MIN ( ");
464 /* Printing Objective */
465 xbt_swag_t var_list = &variable_set;
466 xbt_swag_foreach(_var, var_list)
468 lmm_variable_t var = (lmm_variable_t)_var;
469 buf = buf + "'" + std::to_string(var->id_int) + "'(" + std::to_string(var->sharing_weight) + ") ";
472 XBT_DEBUG("%20s", buf.c_str());
475 XBT_DEBUG("Constraints");
476 /* Printing Constraints */
478 xbt_swag_t cnst_list = &active_constraint_set;
479 xbt_swag_foreach(_cnst, cnst_list)
481 lmm_constraint_t cnst = (lmm_constraint_t)_cnst;
483 // Show the enabled variables
485 buf += ((cnst->sharing_policy) ? "(" : "max(");
486 format_lmm_element_swag(&cnst->enabled_element_set, cnst->sharing_policy, sum, buf);
487 // TODO: Adding disabled elements only for test compatibility, but do we really want them to be printed?
488 format_lmm_element_swag(&cnst->disabled_element_set, cnst->sharing_policy, sum, buf);
490 buf = buf + "0) <= " + std::to_string(cnst->bound) + " ('" + std::to_string(cnst->id_int) + "')";
492 if (not cnst->sharing_policy) {
493 buf += " [MAX-Constraint]";
495 XBT_DEBUG("%s", buf.c_str());
497 xbt_assert(not double_positive(sum - cnst->bound, cnst->bound * sg_maxmin_precision),
498 "Incorrect value (%f is not smaller than %f): %g", sum, cnst->bound, sum - cnst->bound);
501 XBT_DEBUG("Variables");
502 /* Printing Result */
503 xbt_swag_foreach(_var, var_list)
505 lmm_variable_t var = (lmm_variable_t)_var;
506 if (var->bound > 0) {
507 XBT_DEBUG("'%d'(%f) : %f (<=%f)", var->id_int, var->sharing_weight, var->value, var->bound);
508 xbt_assert(not double_positive(var->value - var->bound, var->bound * sg_maxmin_precision),
509 "Incorrect value (%f is not smaller than %f", var->value, var->bound);
511 XBT_DEBUG("'%d'(%f) : %f", var->id_int, var->sharing_weight, var->value);
516 void s_lmm_system_t::solve()
521 double min_usage = -1;
522 double min_bound = -1;
527 XBT_IN("(sys=%p)", this);
529 /* Compute Usage and store the variables that reach the maximum. If selective_update_active is true, only constraints
530 * that changed are considered. Otherwise all constraints with active actions are considered.
532 xbt_swag_t cnst_list = selective_update_active ? &modified_constraint_set : &active_constraint_set;
534 XBT_DEBUG("Active constraints : %d", xbt_swag_size(cnst_list));
535 /* Init: Only modified code portions: reset the value of active variables */
536 xbt_swag_foreach(_cnst, cnst_list)
538 lmm_constraint_t cnst = (lmm_constraint_t)_cnst;
539 xbt_swag_t elem_list = &(cnst->enabled_element_set);
540 xbt_swag_foreach(_elem, elem_list)
542 lmm_variable_t var = ((lmm_element_t)_elem)->variable;
543 xbt_assert(var->sharing_weight > 0.0);
548 s_lmm_constraint_light_t* cnst_light_tab = new s_lmm_constraint_light_t[xbt_swag_size(cnst_list)]();
549 int cnst_light_num = 0;
550 dyn_light_t saturated_constraints;
552 xbt_swag_foreach_safe(_cnst, _cnst_next, cnst_list)
554 lmm_constraint_t cnst = (lmm_constraint_t)_cnst;
555 /* INIT: Collect constraints that actually need to be saturated (i.e remaining and usage are strictly positive)
556 * into cnst_light_tab. */
557 cnst->remaining = cnst->bound;
558 if (not double_positive(cnst->remaining, cnst->bound * sg_maxmin_precision))
561 xbt_swag_t elem_list = &(cnst->enabled_element_set);
562 xbt_swag_foreach(_elem, elem_list)
564 lmm_element_t elem = (lmm_element_t)_elem;
565 xbt_assert(elem->variable->sharing_weight > 0);
566 if (elem->consumption_weight > 0) {
567 if (cnst->sharing_policy)
568 cnst->usage += elem->consumption_weight / elem->variable->sharing_weight;
569 else if (cnst->usage < elem->consumption_weight / elem->variable->sharing_weight)
570 cnst->usage = elem->consumption_weight / elem->variable->sharing_weight;
573 simgrid::surf::Action* action = static_cast<simgrid::surf::Action*>(elem->variable->id);
574 if (keep_track && not action->is_linked())
575 keep_track->push_back(*action);
578 XBT_DEBUG("Constraint '%d' usage: %f remaining: %f concurrency: %i<=%i<=%i", cnst->id_int, cnst->usage,
579 cnst->remaining, cnst->concurrency_current, cnst->concurrency_maximum, cnst->get_concurrency_limit());
580 /* Saturated constraints update */
582 if (cnst->usage > 0) {
583 cnst_light_tab[cnst_light_num].cnst = cnst;
584 cnst->cnst_light = &(cnst_light_tab[cnst_light_num]);
585 cnst_light_tab[cnst_light_num].remaining_over_usage = cnst->remaining / cnst->usage;
586 saturated_constraints_update(cnst_light_tab[cnst_light_num].remaining_over_usage, cnst_light_num,
587 saturated_constraints, &min_usage);
588 xbt_assert(cnst->active_element_set.count > 0,
589 "There is no sense adding a constraint that has no active element!");
594 saturated_variable_set_update(cnst_light_tab, saturated_constraints, this);
596 /* Saturated variables update */
598 /* Fix the variables that have to be */
599 xbt_swag_t var_list = &saturated_variable_set;
601 lmm_variable_t var = nullptr;
602 xbt_swag_foreach(_var, var_list)
604 var = (lmm_variable_t)_var;
605 if (var->sharing_weight <= 0.0)
607 /* First check if some of these variables could reach their upper bound and update min_bound accordingly. */
608 XBT_DEBUG("var=%d, var->bound=%f, var->weight=%f, min_usage=%f, var->bound*var->weight=%f", var->id_int,
609 var->bound, var->sharing_weight, min_usage, var->bound * var->sharing_weight);
610 if ((var->bound > 0) && (var->bound * var->sharing_weight < min_usage)) {
612 min_bound = var->bound * var->sharing_weight;
614 min_bound = std::min(min_bound, (var->bound * var->sharing_weight));
615 XBT_DEBUG("Updated min_bound=%f", min_bound);
619 while ((var = (lmm_variable_t)xbt_swag_getFirst(var_list))) {
621 // If no variable could reach its bound, deal iteratively the constraints usage ( at worst one constraint is
622 // saturated at each cycle)
623 var->value = min_usage / var->sharing_weight;
624 XBT_DEBUG("Setting var (%d) value to %f\n", var->id_int, var->value);
626 // If there exist a variable that can reach its bound, only update it (and other with the same bound) for now.
627 if (double_equals(min_bound, var->bound * var->sharing_weight, sg_maxmin_precision)) {
628 var->value = var->bound;
629 XBT_DEBUG("Setting %p (%d) value to %f\n", var, var->id_int, var->value);
631 // Variables which bound is different are not considered for this cycle, but they will be afterwards.
632 XBT_DEBUG("Do not consider %p (%d) \n", var, var->id_int);
633 xbt_swag_remove(var, var_list);
637 XBT_DEBUG("Min usage: %f, Var(%d)->weight: %f, Var(%d)->value: %f ", min_usage, var->id_int, var->sharing_weight,
638 var->id_int, var->value);
640 /* Update the usage of contraints where this variable is involved */
641 for (s_lmm_element_t& elem : var->cnsts) {
642 lmm_constraint_t cnst = elem.constraint;
643 if (cnst->sharing_policy) {
644 // Remember: shared constraints require that sum(elem.value * var->value) < cnst->bound
645 double_update(&(cnst->remaining), elem.consumption_weight * var->value, cnst->bound * sg_maxmin_precision);
646 double_update(&(cnst->usage), elem.consumption_weight / var->sharing_weight, sg_maxmin_precision);
647 // If the constraint is saturated, remove it from the set of active constraints (light_tab)
648 if (not double_positive(cnst->usage, sg_maxmin_precision) ||
649 not double_positive(cnst->remaining, cnst->bound * sg_maxmin_precision)) {
650 if (cnst->cnst_light) {
651 int index = (cnst->cnst_light - cnst_light_tab);
652 XBT_DEBUG("index: %d \t cnst_light_num: %d \t || usage: %f remaining: %f bound: %f ", index,
653 cnst_light_num, cnst->usage, cnst->remaining, cnst->bound);
654 cnst_light_tab[index] = cnst_light_tab[cnst_light_num - 1];
655 cnst_light_tab[index].cnst->cnst_light = &cnst_light_tab[index];
657 cnst->cnst_light = nullptr;
660 cnst->cnst_light->remaining_over_usage = cnst->remaining / cnst->usage;
662 elem.make_inactive();
664 // Remember: non-shared constraints only require that max(elem.value * var->value) < cnst->bound
666 elem.make_inactive();
667 xbt_swag_t elem_list = &(cnst->enabled_element_set);
668 xbt_swag_foreach(_elem, elem_list)
670 lmm_element_t elem2 = static_cast<lmm_element_t>(_elem);
671 xbt_assert(elem2->variable->sharing_weight > 0);
672 if (elem2->variable->value > 0)
674 if (elem2->consumption_weight > 0)
675 cnst->usage = std::max(cnst->usage, elem2->consumption_weight / elem2->variable->sharing_weight);
677 // If the constraint is saturated, remove it from the set of active constraints (light_tab)
678 if (not double_positive(cnst->usage, sg_maxmin_precision) ||
679 not double_positive(cnst->remaining, cnst->bound * sg_maxmin_precision)) {
680 if (cnst->cnst_light) {
681 int index = (cnst->cnst_light - cnst_light_tab);
682 XBT_DEBUG("index: %d \t cnst_light_num: %d \t || \t cnst: %p \t cnst->cnst_light: %p "
683 "\t cnst_light_tab: %p usage: %f remaining: %f bound: %f ",
684 index, cnst_light_num, cnst, cnst->cnst_light, cnst_light_tab, cnst->usage, cnst->remaining,
686 cnst_light_tab[index] = cnst_light_tab[cnst_light_num - 1];
687 cnst_light_tab[index].cnst->cnst_light = &cnst_light_tab[index];
689 cnst->cnst_light = nullptr;
692 cnst->cnst_light->remaining_over_usage = cnst->remaining / cnst->usage;
693 xbt_assert(cnst->active_element_set.count > 0,
694 "Should not keep a maximum constraint that has no active"
695 " element! You want to check the maxmin precision and possible rounding effects.");
699 xbt_swag_remove(var, var_list);
702 /* Find out which variables reach the maximum */
705 saturated_constraints.clear();
707 for (pos = 0; pos < cnst_light_num; pos++) {
708 xbt_assert(cnst_light_tab[pos].cnst->active_element_set.count > 0,
709 "Cannot saturate more a constraint that has"
710 " no active element! You may want to change the maxmin precision (--cfg=maxmin/precision:<new_value>)"
711 " because of possible rounding effects.\n\tFor the record, the usage of this constraint is %g while "
712 "the maxmin precision to which it is compared is %g.\n\tThe usage of the previous constraint is %g.",
713 cnst_light_tab[pos].cnst->usage, sg_maxmin_precision, cnst_light_tab[pos - 1].cnst->usage);
714 saturated_constraints_update(cnst_light_tab[pos].remaining_over_usage, pos, saturated_constraints, &min_usage);
717 saturated_variable_set_update(cnst_light_tab, saturated_constraints, this);
719 } while (cnst_light_num > 0);
722 if (selective_update_active)
723 remove_all_modified_set();
725 if (XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug)) {
731 delete[] cnst_light_tab;
735 void lmm_solve(lmm_system_t sys)
740 /** \brief Attribute the value bound to var->bound.
742 * \param sys the lmm_system_t
743 * \param var the lmm_variable_t
744 * \param bound the new bound to associate with var
746 * Makes var->bound equal to bound. Whenever this function is called a change is signed in the system. To
747 * avoid false system changing detection it is a good idea to test (bound != 0) before calling it.
749 void s_lmm_system_t::update_variable_bound(lmm_variable_t var, double bound)
754 if (not var->cnsts.empty())
755 update_modified_set(var->cnsts[0].constraint);
758 void s_lmm_variable_t::initialize(simgrid::surf::Action* id_value, double sharing_weight_value, double bound_value,
759 int number_of_constraints, unsigned visited_value)
762 id_int = Global_debug_id++;
763 cnsts.reserve(number_of_constraints);
764 sharing_weight = sharing_weight_value;
767 concurrency_share = 1;
769 visited = visited_value;
773 func_fp = func_fp_def;
774 func_fpi = func_fpi_def;
776 variable_set_hookup.next = nullptr;
777 variable_set_hookup.prev = nullptr;
778 saturated_variable_set_hookup.next = nullptr;
779 saturated_variable_set_hookup.prev = nullptr;
782 int s_lmm_variable_t::get_min_concurrency_slack() const
784 int minslack = std::numeric_limits<int>::max();
785 for (s_lmm_element_t const& elem : cnsts) {
786 int slack = elem.constraint->get_concurrency_slack();
787 if (slack < minslack) {
788 // This is only an optimization, to avoid looking at more constraints when slack is already zero
797 // Small remark: In this implementation of lmm_enable_var and lmm_disable_var, we will meet multiple times with var when
798 // running sys->update_modified_set.
799 // A priori not a big performance issue, but we might do better by calling sys->update_modified_set within the for loops
800 // (after doing the first for enabling==1, and before doing the last for disabling==1)
801 void s_lmm_system_t::enable_var(lmm_variable_t var)
803 xbt_assert(not XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug) || var->can_enable());
805 var->sharing_weight = var->staged_weight;
806 var->staged_weight = 0;
808 // Enabling the variable, move to var to list head. Subtlety is: here, we need to call update_modified_set AFTER
809 // moving at least one element of var.
811 xbt_swag_remove(var, &variable_set);
812 xbt_swag_insert_at_head(var, &variable_set);
813 for (s_lmm_element_t& elem : var->cnsts) {
814 xbt_swag_remove(&elem, &(elem.constraint->disabled_element_set));
815 xbt_swag_insert_at_head(&elem, &(elem.constraint->enabled_element_set));
816 elem.increase_concurrency();
818 if (not var->cnsts.empty())
819 update_modified_set(var->cnsts[0].constraint);
821 // When used within on_disabled_var, we would get an assertion fail, because transiently there can be variables
822 // that are staged and could be activated.
823 // Anyway, caller functions all call check_concurrency() in the end.
826 void s_lmm_system_t::disable_var(lmm_variable_t var)
828 xbt_assert(not var->staged_weight, "Staged weight should have been cleared");
829 // Disabling the variable, move to var to list tail. Subtlety is: here, we need to call update_modified_set
830 // BEFORE moving the last element of var.
831 xbt_swag_remove(var, &variable_set);
832 xbt_swag_insert_at_tail(var, &variable_set);
833 if (not var->cnsts.empty())
834 update_modified_set(var->cnsts[0].constraint);
835 for (s_lmm_element_t& elem : var->cnsts) {
836 xbt_swag_remove(&elem, &(elem.constraint->enabled_element_set));
837 xbt_swag_insert_at_tail(&elem, &(elem.constraint->disabled_element_set));
839 xbt_swag_remove(&elem, &(elem.constraint->active_element_set));
841 elem.decrease_concurrency();
844 var->sharing_weight = 0.0;
845 var->staged_weight = 0.0;
850 /* /brief Find variables that can be enabled and enable them.
852 * Assuming that the variable has already been removed from non-zero weights
853 * Can we find a staged variable to add?
854 * If yes, check that none of the constraints that this variable is involved in is at the limit of its concurrency
855 * And then add it to enabled variables
857 void s_lmm_system_t::on_disabled_var(lmm_constraint_t cnstr)
859 if (cnstr->get_concurrency_limit() < 0)
862 int numelem = xbt_swag_size(&(cnstr->disabled_element_set));
866 lmm_element_t elem = (lmm_element_t)xbt_swag_getFirst(&(cnstr->disabled_element_set));
868 // Cannot use xbt_swag_foreach, because lmm_enable_var will modify disabled_element_set.. within the loop
869 while (numelem-- && elem) {
871 lmm_element_t nextelem = (lmm_element_t)xbt_swag_getNext(elem, cnstr->disabled_element_set.offset);
873 if (elem->variable->staged_weight > 0 && elem->variable->can_enable()) {
874 // Found a staged variable
875 // TODOLATER: Add random timing function to model reservation protocol fuzziness? Then how to make sure that
876 // staged variables will eventually be called?
877 enable_var(elem->variable);
880 xbt_assert(cnstr->concurrency_current <= cnstr->get_concurrency_limit(), "Concurrency overflow!");
881 if (cnstr->concurrency_current == cnstr->get_concurrency_limit())
887 // We could get an assertion fail, because transiently there can be variables that are staged and could be activated.
888 // And we need to go through all constraints of the disabled var before getting back a coherent state.
889 // Anyway, caller functions all call check_concurrency() in the end.
892 /* \brief update the weight of a variable, and enable/disable it.
893 * @return Returns whether a change was made
895 void s_lmm_system_t::update_variable_weight(lmm_variable_t var, double weight)
897 xbt_assert(weight >= 0, "Variable weight should not be negative!");
899 if (weight == var->sharing_weight)
902 int enabling_var = (weight > 0 && var->sharing_weight <= 0);
903 int disabling_var = (weight <= 0 && var->sharing_weight > 0);
905 XBT_IN("(sys=%p, var=%p, weight=%f)", this, var, weight);
909 // Are we enabling this variable?
911 var->staged_weight = weight;
912 int minslack = var->get_min_concurrency_slack();
913 if (minslack < var->concurrency_share) {
914 XBT_DEBUG("Staging var (instead of enabling) because min concurrency slack %i, with weight %f and concurrency"
916 minslack, weight, var->concurrency_share);
919 XBT_DEBUG("Enabling var with min concurrency slack %i", minslack);
921 } else if (disabling_var) {
922 // Are we disabling this variable?
925 var->sharing_weight = weight;
933 void s_lmm_system_t::update_constraint_bound(lmm_constraint_t cnst, double bound)
936 update_modified_set(cnst);
940 /** \brief Update the constraint set propagating recursively to other constraints so the system should not be entirely
943 * \param sys the lmm_system_t
944 * \param cnst the lmm_constraint_t affected by the change
946 * A recursive algorithm to optimize the system recalculation selecting only constraints that have changed. Each
947 * constraint change is propagated to the list of constraints for each variable.
949 void s_lmm_system_t::update_modified_set_rec(lmm_constraint_t cnst)
953 xbt_swag_foreach(_elem, &cnst->enabled_element_set)
955 lmm_variable_t var = ((lmm_element_t)_elem)->variable;
956 for (s_lmm_element_t const& elem : var->cnsts) {
957 if (var->visited == visited_counter)
959 if (elem.constraint != cnst && not xbt_swag_belongs(elem.constraint, &modified_constraint_set)) {
960 xbt_swag_insert(elem.constraint, &modified_constraint_set);
961 update_modified_set_rec(elem.constraint);
964 // var will be ignored in later visits as long as sys->visited_counter does not move
965 var->visited = visited_counter;
969 void s_lmm_system_t::update_modified_set(lmm_constraint_t cnst)
971 /* nothing to do if selective update isn't active */
972 if (selective_update_active && not xbt_swag_belongs(cnst, &modified_constraint_set)) {
973 xbt_swag_insert(cnst, &modified_constraint_set);
974 update_modified_set_rec(cnst);
978 void s_lmm_system_t::remove_all_modified_set()
980 // We cleverly un-flag all variables just by incrementing visited_counter
981 // In effect, the var->visited value will no more be equal to visited counter
982 // To be clean, when visited counter has wrapped around, we force these var->visited values so that variables that
983 // were in the modified a long long time ago are not wrongly skipped here, which would lead to very nasty bugs
984 // (i.e. not readibily reproducible, and requiring a lot of run time before happening).
985 if (++visited_counter == 1) {
986 /* the counter wrapped around, reset each variable->visited */
988 xbt_swag_foreach(_var, &variable_set)((lmm_variable_t)_var)->visited = 0;
990 xbt_swag_reset(&modified_constraint_set);
994 * Returns resource load (in flop per second, or byte per second, or similar)
996 * If the resource is shared (the default case), the load is sum of resource usage made by every variables located on
999 * If the resource is not shared (ie in FATPIPE mode), then the load is the max (not the sum) of all resource usages
1000 * located on this resource.
1002 * \param cnst the lmm_constraint_t associated to the resource
1004 double s_lmm_constraint_t::get_usage() const
1006 double result = 0.0;
1007 const_xbt_swag_t elem_list = &enabled_element_set;
1010 xbt_swag_foreach(_elem, elem_list)
1012 lmm_element_t elem = (lmm_element_t)_elem;
1013 if (elem->consumption_weight > 0) {
1015 result += elem->consumption_weight * elem->variable->value;
1016 else if (result < elem->consumption_weight * elem->variable->value)
1017 result = std::max(result, elem->consumption_weight * elem->variable->value);
1023 int s_lmm_constraint_t::get_variable_amount() const
1026 const_xbt_swag_t elem_list = &enabled_element_set;
1029 xbt_swag_foreach(_elem, elem_list)
1031 lmm_element_t elem = (lmm_element_t)_elem;
1032 if (elem->consumption_weight > 0)