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() const
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))
71 for (s_lmm_constraint_t const& cnst : constraint_set) {
74 xbt_swag_foreach(elemIt, &cnst.enabled_element_set)
76 lmm_element_t elem = (lmm_element_t)elemIt;
77 xbt_assert(elem->variable->sharing_weight > 0);
78 concurrency += elem->get_concurrency();
81 xbt_swag_foreach(elemIt, &cnst.disabled_element_set)
83 lmm_element_t elem = (lmm_element_t)elemIt;
84 // We should have staged variables only if concurrency is reached in some constraint
85 xbt_assert(cnst.get_concurrency_limit() < 0 || elem->variable->staged_weight == 0 ||
86 elem->variable->get_min_concurrency_slack() < elem->variable->concurrency_share,
87 "should not have staged variable!");
90 xbt_assert(cnst.get_concurrency_limit() < 0 || cnst.get_concurrency_limit() >= concurrency,
91 "concurrency check failed!");
92 xbt_assert(cnst.concurrency_current == concurrency, "concurrency_current is out-of-date!");
95 // Check that for each variable, all corresponding elements are in the same state (i.e. same element sets)
97 xbt_swag_foreach(varIt, &variable_set)
99 lmm_variable_t var = (lmm_variable_t)varIt;
101 if (var->cnsts.empty())
104 lmm_element_t elem = &var->cnsts[0];
105 int belong_to_enabled = xbt_swag_belongs(elem, &(elem->constraint->enabled_element_set));
106 int belong_to_disabled = xbt_swag_belongs(elem, &(elem->constraint->disabled_element_set));
107 int belong_to_active = xbt_swag_belongs(elem, &(elem->constraint->active_element_set));
109 for (s_lmm_element_t const& elem : var->cnsts) {
110 xbt_assert(belong_to_enabled == xbt_swag_belongs(&elem, &(elem.constraint->enabled_element_set)),
111 "Variable inconsistency (1): enabled_element_set");
112 xbt_assert(belong_to_disabled == xbt_swag_belongs(&elem, &(elem.constraint->disabled_element_set)),
113 "Variable inconsistency (2): disabled_element_set");
114 xbt_assert(belong_to_active == xbt_swag_belongs(&elem, &(elem.constraint->active_element_set)),
115 "Variable inconsistency (3): active_element_set");
120 void s_lmm_system_t::var_free(lmm_variable_t var)
122 XBT_IN("(sys=%p, var=%p)", this, var);
125 // TODOLATER Can do better than that by leaving only the variable in only one enabled_element_set, call
126 // update_modified_set, and then remove it..
127 if (not var->cnsts.empty())
128 update_modified_set(var->cnsts[0].constraint);
130 for (s_lmm_element_t& elem : var->cnsts) {
131 if (var->sharing_weight > 0)
132 elem.decrease_concurrency();
133 xbt_swag_remove(&elem, &(elem.constraint->enabled_element_set));
134 xbt_swag_remove(&elem, &(elem.constraint->disabled_element_set));
135 xbt_swag_remove(&elem, &(elem.constraint->active_element_set));
136 int nelements = xbt_swag_size(&(elem.constraint->enabled_element_set)) +
137 xbt_swag_size(&(elem.constraint->disabled_element_set));
139 make_constraint_inactive(elem.constraint);
141 on_disabled_var(elem.constraint);
148 xbt_mallocator_release(variable_mallocator, var);
152 s_lmm_system_t::s_lmm_system_t(bool selective_update) : selective_update_active(selective_update)
154 s_lmm_variable_t var;
155 s_lmm_constraint_t cnst;
160 XBT_DEBUG("Setting selective_update_active flag to %d", selective_update_active);
162 xbt_swag_init(&variable_set, xbt_swag_offset(var, variable_set_hookup));
163 xbt_swag_init(&saturated_variable_set, xbt_swag_offset(var, saturated_variable_set_hookup));
165 keep_track = nullptr;
166 variable_mallocator = xbt_mallocator_new(65536, s_lmm_system_t::variable_mallocator_new_f,
167 s_lmm_system_t::variable_mallocator_free_f, nullptr);
168 solve_fun = &lmm_solve;
171 s_lmm_system_t::~s_lmm_system_t()
174 lmm_constraint_t cnst;
176 while ((var = extract_variable())) {
177 auto demangled = simgrid::xbt::demangle(typeid(*var->id).name());
178 XBT_WARN("Probable bug: a %s variable (#%d) not removed before the LMM system destruction.", demangled.get(),
182 while ((cnst = extract_constraint()))
185 xbt_mallocator_free(variable_mallocator);
188 void s_lmm_system_t::cnst_free(lmm_constraint_t cnst)
190 make_constraint_inactive(cnst);
194 s_lmm_constraint_t::s_lmm_constraint_t(void* id_value, double bound_value) : bound(bound_value), id(id_value)
196 s_lmm_element_t elem;
198 id_int = Global_debug_id++;
199 xbt_swag_init(&enabled_element_set, xbt_swag_offset(elem, enabled_element_set_hookup));
200 xbt_swag_init(&disabled_element_set, xbt_swag_offset(elem, disabled_element_set_hookup));
201 xbt_swag_init(&active_element_set, xbt_swag_offset(elem, active_element_set_hookup));
205 concurrency_limit = sg_concurrency_limit;
206 concurrency_current = 0;
207 concurrency_maximum = 0;
208 sharing_policy = 1; /* FIXME: don't hardcode the value */
212 cnst_light = nullptr;
215 lmm_constraint_t s_lmm_system_t::constraint_new(void* id, double bound_value)
217 lmm_constraint_t cnst = new s_lmm_constraint_t(id, bound_value);
218 insert_constraint(cnst);
222 void* s_lmm_system_t::variable_mallocator_new_f()
224 return new s_lmm_variable_t;
227 void s_lmm_system_t::variable_mallocator_free_f(void* var)
229 delete static_cast<lmm_variable_t>(var);
232 lmm_variable_t s_lmm_system_t::variable_new(simgrid::surf::Action* id, double sharing_weight, double bound,
233 int number_of_constraints)
235 XBT_IN("(sys=%p, id=%p, weight=%f, bound=%f, num_cons =%d)", this, id, sharing_weight, bound, number_of_constraints);
237 lmm_variable_t var = static_cast<lmm_variable_t>(xbt_mallocator_get(variable_mallocator));
238 var->initialize(id, sharing_weight, bound, number_of_constraints, visited_counter - 1);
240 xbt_swag_insert_at_head(var, &variable_set);
242 xbt_swag_insert_at_tail(var, &variable_set);
244 XBT_OUT(" returns %p", var);
248 void s_lmm_system_t::variable_free(lmm_variable_t var)
250 remove_variable(var);
254 void s_lmm_system_t::expand(lmm_constraint_t cnst, lmm_variable_t var, double consumption_weight)
258 // Check if this variable already has an active element in this constraint
259 // If it does, substract it from the required slack
260 int current_share = 0;
261 if (var->concurrency_share > 1) {
262 for (s_lmm_element_t& elem : var->cnsts) {
263 if (elem.constraint == cnst && xbt_swag_belongs(&elem, &(elem.constraint->enabled_element_set)))
264 current_share += elem.get_concurrency();
268 // Check if we need to disable the variable
269 if (var->sharing_weight > 0 && var->concurrency_share - current_share > cnst->get_concurrency_slack()) {
270 double weight = var->sharing_weight;
272 for (s_lmm_element_t const& elem : var->cnsts)
273 on_disabled_var(elem.constraint);
274 consumption_weight = 0;
275 var->staged_weight = weight;
276 xbt_assert(not var->sharing_weight);
279 xbt_assert(var->cnsts.size() < var->cnsts.capacity(), "Too much constraints");
281 var->cnsts.resize(var->cnsts.size() + 1);
282 s_lmm_element_t& elem = var->cnsts.back();
284 elem.consumption_weight = consumption_weight;
285 elem.constraint = cnst;
288 if (var->sharing_weight) {
289 xbt_swag_insert_at_head(&elem, &(elem.constraint->enabled_element_set));
290 elem.increase_concurrency();
292 xbt_swag_insert_at_tail(&elem, &(elem.constraint->disabled_element_set));
294 if (not selective_update_active) {
295 make_constraint_active(cnst);
296 } else if (elem.consumption_weight > 0 || var->sharing_weight > 0) {
297 make_constraint_active(cnst);
298 update_modified_set(cnst);
299 // TODOLATER: Why do we need this second call?
300 if (var->cnsts.size() > 1)
301 update_modified_set(var->cnsts[0].constraint);
307 void s_lmm_system_t::expand_add(lmm_constraint_t cnst, lmm_variable_t var, double value)
313 // BEWARE: In case you have multiple elements in one constraint, this will always add value to the first element.
314 auto elem_it = std::find_if(begin(var->cnsts), end(var->cnsts),
315 [&cnst](s_lmm_element_t const& x) { return x.constraint == cnst; });
316 if (elem_it != end(var->cnsts)) {
317 s_lmm_element_t& elem = *elem_it;
318 if (var->sharing_weight)
319 elem.decrease_concurrency();
321 if (cnst->sharing_policy)
322 elem.consumption_weight += value;
324 elem.consumption_weight = std::max(elem.consumption_weight, value);
326 // We need to check that increasing value of the element does not cross the concurrency limit
327 if (var->sharing_weight) {
328 if (cnst->get_concurrency_slack() < elem.get_concurrency()) {
329 double weight = var->sharing_weight;
331 for (s_lmm_element_t const& elem2 : var->cnsts)
332 on_disabled_var(elem2.constraint);
333 var->staged_weight = weight;
334 xbt_assert(not var->sharing_weight);
336 elem.increase_concurrency();
338 update_modified_set(cnst);
340 expand(cnst, var, value);
345 lmm_variable_t s_lmm_constraint_t::get_variable(const_lmm_element_t* elem) const
347 if (*elem == nullptr) {
348 // That is the first call, pick the first element among enabled_element_set (or disabled_element_set if
349 // enabled_element_set is empty)
350 *elem = (lmm_element_t)xbt_swag_getFirst(&enabled_element_set);
351 if (*elem == nullptr)
352 *elem = (lmm_element_t)xbt_swag_getFirst(&disabled_element_set);
354 // elem is not null, so we carry on
355 if (xbt_swag_belongs(*elem, &enabled_element_set)) {
356 // Look at enabled_element_set, and jump to disabled_element_set when finished
357 *elem = (lmm_element_t)xbt_swag_getNext(*elem, enabled_element_set.offset);
358 if (*elem == nullptr)
359 *elem = (lmm_element_t)xbt_swag_getFirst(&disabled_element_set);
361 *elem = (lmm_element_t)xbt_swag_getNext(*elem, disabled_element_set.offset);
365 return (*elem)->variable;
370 // if we modify the swag between calls, normal version may loop forever
371 // this safe version ensures that we browse the swag elements only once
372 lmm_variable_t s_lmm_constraint_t::get_variable_safe(const_lmm_element_t* elem, const_lmm_element_t* nextelem,
375 if (*elem == nullptr) {
376 *elem = (lmm_element_t)xbt_swag_getFirst(&enabled_element_set);
377 *numelem = xbt_swag_size(&enabled_element_set) + xbt_swag_size(&disabled_element_set) - 1;
378 if (*elem == nullptr)
379 *elem = (lmm_element_t)xbt_swag_getFirst(&disabled_element_set);
388 // elem is not null, so we carry on
389 if (xbt_swag_belongs(*elem, &enabled_element_set)) {
390 // Look at enabled_element_set, and jump to disabled_element_set when finished
391 *nextelem = (lmm_element_t)xbt_swag_getNext(*elem, enabled_element_set.offset);
392 if (*nextelem == nullptr)
393 *nextelem = (lmm_element_t)xbt_swag_getFirst(&disabled_element_set);
395 *nextelem = (lmm_element_t)xbt_swag_getNext(*elem, disabled_element_set.offset);
397 return (*elem)->variable;
402 static inline void saturated_constraints_update(double usage, int cnst_light_num, dyn_light_t& saturated_constraints,
405 xbt_assert(usage > 0, "Impossible");
407 if (*min_usage < 0 || *min_usage > usage) {
409 XBT_HERE(" min_usage=%f (cnst->remaining / cnst->usage =%f)", *min_usage, usage);
410 saturated_constraints.assign(1, cnst_light_num);
411 } else if (*min_usage == usage) {
412 saturated_constraints.emplace_back(cnst_light_num);
416 static inline void saturated_variable_set_update(s_lmm_constraint_light_t* cnst_light_tab,
417 const dyn_light_t& saturated_constraints, lmm_system_t sys)
419 /* Add active variables (i.e. variables that need to be set) from the set of constraints to saturate
421 for (int const& saturated_cnst : saturated_constraints) {
422 lmm_constraint_light_t cnst = &cnst_light_tab[saturated_cnst];
424 xbt_swag_t elem_list = &(cnst->cnst->active_element_set);
425 xbt_swag_foreach(_elem, elem_list)
427 lmm_element_t elem = (lmm_element_t)_elem;
428 // Visiting active_element_set, so, by construction, should never get a zero weight, correct?
429 xbt_assert(elem->variable->sharing_weight > 0);
430 if (elem->consumption_weight > 0)
431 xbt_swag_insert(elem->variable, &(sys->saturated_variable_set));
436 static void format_lmm_element_swag(const_xbt_swag_t elem_list, int sharing_policy, double& sum, std::string& buf)
439 xbt_swag_foreach(_elem, elem_list)
441 lmm_element_t elem = (lmm_element_t)_elem;
442 buf += std::to_string(elem->consumption_weight) + ".'" + std::to_string(elem->variable->id_int) + "'(" +
443 std::to_string(elem->variable->value) + ")" + (sharing_policy ? " + " : " , ");
445 sum += elem->consumption_weight * elem->variable->value;
447 sum = std::max(sum, elem->consumption_weight * elem->variable->value);
451 void s_lmm_system_t::print() const
453 std::string buf = std::string("MAX-MIN ( ");
456 /* Printing Objective */
457 const_xbt_swag_t var_list = &variable_set;
458 xbt_swag_foreach(_var, var_list)
460 lmm_variable_t var = (lmm_variable_t)_var;
461 buf = buf + "'" + std::to_string(var->id_int) + "'(" + std::to_string(var->sharing_weight) + ") ";
464 XBT_DEBUG("%20s", buf.c_str());
467 XBT_DEBUG("Constraints");
468 /* Printing Constraints */
469 for (s_lmm_constraint_t const& cnst : active_constraint_set) {
471 // Show the enabled variables
473 buf += cnst.sharing_policy ? "(" : "max(";
474 format_lmm_element_swag(&cnst.enabled_element_set, cnst.sharing_policy, sum, buf);
475 // TODO: Adding disabled elements only for test compatibility, but do we really want them to be printed?
476 format_lmm_element_swag(&cnst.disabled_element_set, cnst.sharing_policy, sum, buf);
478 buf += "0) <= " + std::to_string(cnst.bound) + " ('" + std::to_string(cnst.id_int) + "')";
480 if (not cnst.sharing_policy) {
481 buf += " [MAX-Constraint]";
483 XBT_DEBUG("%s", buf.c_str());
485 xbt_assert(not double_positive(sum - cnst.bound, cnst.bound * sg_maxmin_precision),
486 "Incorrect value (%f is not smaller than %f): %g", sum, cnst.bound, sum - cnst.bound);
489 XBT_DEBUG("Variables");
490 /* Printing Result */
491 xbt_swag_foreach(_var, var_list)
493 lmm_variable_t var = (lmm_variable_t)_var;
494 if (var->bound > 0) {
495 XBT_DEBUG("'%d'(%f) : %f (<=%f)", var->id_int, var->sharing_weight, var->value, var->bound);
496 xbt_assert(not double_positive(var->value - var->bound, var->bound * sg_maxmin_precision),
497 "Incorrect value (%f is not smaller than %f", var->value, var->bound);
499 XBT_DEBUG("'%d'(%f) : %f", var->id_int, var->sharing_weight, var->value);
504 void s_lmm_system_t::solve()
507 XBT_IN("(sys=%p)", this);
508 /* Compute Usage and store the variables that reach the maximum. If selective_update_active is true, only
509 * constraints that changed are considered. Otherwise all constraints with active actions are considered.
511 if (selective_update_active)
512 solve(modified_constraint_set);
514 solve(active_constraint_set);
519 template <class CnstList> void s_lmm_system_t::solve(CnstList& cnst_list)
522 double min_usage = -1;
523 double min_bound = -1;
525 XBT_DEBUG("Active constraints : %zu", cnst_list.size());
526 /* Init: Only modified code portions: reset the value of active variables */
527 for (s_lmm_constraint_t const& cnst : cnst_list) {
528 const_xbt_swag_t elem_list = &cnst.enabled_element_set;
529 xbt_swag_foreach(_elem, elem_list)
531 lmm_variable_t var = ((lmm_element_t)_elem)->variable;
532 xbt_assert(var->sharing_weight > 0.0);
537 s_lmm_constraint_light_t* cnst_light_tab = new s_lmm_constraint_light_t[cnst_list.size()]();
538 int cnst_light_num = 0;
539 dyn_light_t saturated_constraints;
541 for (s_lmm_constraint_t& cnst : cnst_list) {
542 /* INIT: Collect constraints that actually need to be saturated (i.e remaining and usage are strictly positive)
543 * into cnst_light_tab. */
544 cnst.remaining = cnst.bound;
545 if (not double_positive(cnst.remaining, cnst.bound * sg_maxmin_precision))
548 xbt_swag_t elem_list = &cnst.enabled_element_set;
549 xbt_swag_foreach(_elem, elem_list)
551 lmm_element_t elem = (lmm_element_t)_elem;
552 xbt_assert(elem->variable->sharing_weight > 0);
553 if (elem->consumption_weight > 0) {
554 if (cnst.sharing_policy)
555 cnst.usage += elem->consumption_weight / elem->variable->sharing_weight;
556 else if (cnst.usage < elem->consumption_weight / elem->variable->sharing_weight)
557 cnst.usage = elem->consumption_weight / elem->variable->sharing_weight;
560 simgrid::surf::Action* action = static_cast<simgrid::surf::Action*>(elem->variable->id);
561 if (keep_track && not action->is_linked())
562 keep_track->push_back(*action);
565 XBT_DEBUG("Constraint '%d' usage: %f remaining: %f concurrency: %i<=%i<=%i", cnst.id_int, cnst.usage,
566 cnst.remaining, cnst.concurrency_current, cnst.concurrency_maximum, cnst.get_concurrency_limit());
567 /* Saturated constraints update */
569 if (cnst.usage > 0) {
570 cnst_light_tab[cnst_light_num].cnst = &cnst;
571 cnst.cnst_light = &cnst_light_tab[cnst_light_num];
572 cnst_light_tab[cnst_light_num].remaining_over_usage = cnst.remaining / cnst.usage;
573 saturated_constraints_update(cnst_light_tab[cnst_light_num].remaining_over_usage, cnst_light_num,
574 saturated_constraints, &min_usage);
575 xbt_assert(cnst.active_element_set.count > 0,
576 "There is no sense adding a constraint that has no active element!");
581 saturated_variable_set_update(cnst_light_tab, saturated_constraints, this);
583 /* Saturated variables update */
585 /* Fix the variables that have to be */
586 xbt_swag_t var_list = &saturated_variable_set;
588 lmm_variable_t var = nullptr;
589 xbt_swag_foreach(_var, var_list)
591 var = (lmm_variable_t)_var;
592 if (var->sharing_weight <= 0.0)
594 /* First check if some of these variables could reach their upper bound and update min_bound accordingly. */
595 XBT_DEBUG("var=%d, var->bound=%f, var->weight=%f, min_usage=%f, var->bound*var->weight=%f", var->id_int,
596 var->bound, var->sharing_weight, min_usage, var->bound * var->sharing_weight);
597 if ((var->bound > 0) && (var->bound * var->sharing_weight < min_usage)) {
599 min_bound = var->bound * var->sharing_weight;
601 min_bound = std::min(min_bound, (var->bound * var->sharing_weight));
602 XBT_DEBUG("Updated min_bound=%f", min_bound);
606 while ((var = (lmm_variable_t)xbt_swag_getFirst(var_list))) {
608 // If no variable could reach its bound, deal iteratively the constraints usage ( at worst one constraint is
609 // saturated at each cycle)
610 var->value = min_usage / var->sharing_weight;
611 XBT_DEBUG("Setting var (%d) value to %f\n", var->id_int, var->value);
613 // If there exist a variable that can reach its bound, only update it (and other with the same bound) for now.
614 if (double_equals(min_bound, var->bound * var->sharing_weight, sg_maxmin_precision)) {
615 var->value = var->bound;
616 XBT_DEBUG("Setting %p (%d) value to %f\n", var, var->id_int, var->value);
618 // Variables which bound is different are not considered for this cycle, but they will be afterwards.
619 XBT_DEBUG("Do not consider %p (%d) \n", var, var->id_int);
620 xbt_swag_remove(var, var_list);
624 XBT_DEBUG("Min usage: %f, Var(%d)->weight: %f, Var(%d)->value: %f ", min_usage, var->id_int, var->sharing_weight,
625 var->id_int, var->value);
627 /* Update the usage of contraints where this variable is involved */
628 for (s_lmm_element_t& elem : var->cnsts) {
629 lmm_constraint_t cnst = elem.constraint;
630 if (cnst->sharing_policy) {
631 // Remember: shared constraints require that sum(elem.value * var->value) < cnst->bound
632 double_update(&(cnst->remaining), elem.consumption_weight * var->value, cnst->bound * sg_maxmin_precision);
633 double_update(&(cnst->usage), elem.consumption_weight / var->sharing_weight, sg_maxmin_precision);
634 // If the constraint is saturated, remove it from the set of active constraints (light_tab)
635 if (not double_positive(cnst->usage, sg_maxmin_precision) ||
636 not double_positive(cnst->remaining, cnst->bound * sg_maxmin_precision)) {
637 if (cnst->cnst_light) {
638 int index = (cnst->cnst_light - cnst_light_tab);
639 XBT_DEBUG("index: %d \t cnst_light_num: %d \t || usage: %f remaining: %f bound: %f ", index,
640 cnst_light_num, cnst->usage, cnst->remaining, cnst->bound);
641 cnst_light_tab[index] = cnst_light_tab[cnst_light_num - 1];
642 cnst_light_tab[index].cnst->cnst_light = &cnst_light_tab[index];
644 cnst->cnst_light = nullptr;
647 cnst->cnst_light->remaining_over_usage = cnst->remaining / cnst->usage;
649 elem.make_inactive();
651 // Remember: non-shared constraints only require that max(elem.value * var->value) < cnst->bound
653 elem.make_inactive();
654 xbt_swag_t elem_list = &(cnst->enabled_element_set);
655 xbt_swag_foreach(_elem, elem_list)
657 lmm_element_t elem2 = static_cast<lmm_element_t>(_elem);
658 xbt_assert(elem2->variable->sharing_weight > 0);
659 if (elem2->variable->value > 0)
661 if (elem2->consumption_weight > 0)
662 cnst->usage = std::max(cnst->usage, elem2->consumption_weight / elem2->variable->sharing_weight);
664 // If the constraint is saturated, remove it from the set of active constraints (light_tab)
665 if (not double_positive(cnst->usage, sg_maxmin_precision) ||
666 not double_positive(cnst->remaining, cnst->bound * sg_maxmin_precision)) {
667 if (cnst->cnst_light) {
668 int index = (cnst->cnst_light - cnst_light_tab);
669 XBT_DEBUG("index: %d \t cnst_light_num: %d \t || \t cnst: %p \t cnst->cnst_light: %p "
670 "\t cnst_light_tab: %p usage: %f remaining: %f bound: %f ",
671 index, cnst_light_num, cnst, cnst->cnst_light, cnst_light_tab, cnst->usage, cnst->remaining,
673 cnst_light_tab[index] = cnst_light_tab[cnst_light_num - 1];
674 cnst_light_tab[index].cnst->cnst_light = &cnst_light_tab[index];
676 cnst->cnst_light = nullptr;
679 cnst->cnst_light->remaining_over_usage = cnst->remaining / cnst->usage;
680 xbt_assert(cnst->active_element_set.count > 0,
681 "Should not keep a maximum constraint that has no active"
682 " element! You want to check the maxmin precision and possible rounding effects.");
686 xbt_swag_remove(var, var_list);
689 /* Find out which variables reach the maximum */
692 saturated_constraints.clear();
694 for (pos = 0; pos < cnst_light_num; pos++) {
695 xbt_assert(cnst_light_tab[pos].cnst->active_element_set.count > 0,
696 "Cannot saturate more a constraint that has"
697 " no active element! You may want to change the maxmin precision (--cfg=maxmin/precision:<new_value>)"
698 " because of possible rounding effects.\n\tFor the record, the usage of this constraint is %g while "
699 "the maxmin precision to which it is compared is %g.\n\tThe usage of the previous constraint is %g.",
700 cnst_light_tab[pos].cnst->usage, sg_maxmin_precision, cnst_light_tab[pos - 1].cnst->usage);
701 saturated_constraints_update(cnst_light_tab[pos].remaining_over_usage, pos, saturated_constraints, &min_usage);
704 saturated_variable_set_update(cnst_light_tab, saturated_constraints, this);
706 } while (cnst_light_num > 0);
709 if (selective_update_active)
710 remove_all_modified_set();
712 if (XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug)) {
718 delete[] cnst_light_tab;
721 void lmm_solve(lmm_system_t sys)
726 /** \brief Attribute the value bound to var->bound.
728 * \param sys the lmm_system_t
729 * \param var the lmm_variable_t
730 * \param bound the new bound to associate with var
732 * Makes var->bound equal to bound. Whenever this function is called a change is signed in the system. To
733 * avoid false system changing detection it is a good idea to test (bound != 0) before calling it.
735 void s_lmm_system_t::update_variable_bound(lmm_variable_t var, double bound)
740 if (not var->cnsts.empty())
741 update_modified_set(var->cnsts[0].constraint);
744 void s_lmm_variable_t::initialize(simgrid::surf::Action* id_value, double sharing_weight_value, double bound_value,
745 int number_of_constraints, unsigned visited_value)
748 id_int = Global_debug_id++;
749 cnsts.reserve(number_of_constraints);
750 sharing_weight = sharing_weight_value;
753 concurrency_share = 1;
755 visited = visited_value;
759 func_fp = func_fp_def;
760 func_fpi = func_fpi_def;
762 variable_set_hookup.next = nullptr;
763 variable_set_hookup.prev = nullptr;
764 saturated_variable_set_hookup.next = nullptr;
765 saturated_variable_set_hookup.prev = nullptr;
768 int s_lmm_variable_t::get_min_concurrency_slack() const
770 int minslack = std::numeric_limits<int>::max();
771 for (s_lmm_element_t const& elem : cnsts) {
772 int slack = elem.constraint->get_concurrency_slack();
773 if (slack < minslack) {
774 // This is only an optimization, to avoid looking at more constraints when slack is already zero
783 // Small remark: In this implementation of lmm_enable_var and lmm_disable_var, we will meet multiple times with var when
784 // running sys->update_modified_set.
785 // A priori not a big performance issue, but we might do better by calling sys->update_modified_set within the for loops
786 // (after doing the first for enabling==1, and before doing the last for disabling==1)
787 void s_lmm_system_t::enable_var(lmm_variable_t var)
789 xbt_assert(not XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug) || var->can_enable());
791 var->sharing_weight = var->staged_weight;
792 var->staged_weight = 0;
794 // Enabling the variable, move to var to list head. Subtlety is: here, we need to call update_modified_set AFTER
795 // moving at least one element of var.
797 xbt_swag_remove(var, &variable_set);
798 xbt_swag_insert_at_head(var, &variable_set);
799 for (s_lmm_element_t& elem : var->cnsts) {
800 xbt_swag_remove(&elem, &(elem.constraint->disabled_element_set));
801 xbt_swag_insert_at_head(&elem, &(elem.constraint->enabled_element_set));
802 elem.increase_concurrency();
804 if (not var->cnsts.empty())
805 update_modified_set(var->cnsts[0].constraint);
807 // When used within on_disabled_var, we would get an assertion fail, because transiently there can be variables
808 // that are staged and could be activated.
809 // Anyway, caller functions all call check_concurrency() in the end.
812 void s_lmm_system_t::disable_var(lmm_variable_t var)
814 xbt_assert(not var->staged_weight, "Staged weight should have been cleared");
815 // Disabling the variable, move to var to list tail. Subtlety is: here, we need to call update_modified_set
816 // BEFORE moving the last element of var.
817 xbt_swag_remove(var, &variable_set);
818 xbt_swag_insert_at_tail(var, &variable_set);
819 if (not var->cnsts.empty())
820 update_modified_set(var->cnsts[0].constraint);
821 for (s_lmm_element_t& elem : var->cnsts) {
822 xbt_swag_remove(&elem, &(elem.constraint->enabled_element_set));
823 xbt_swag_insert_at_tail(&elem, &(elem.constraint->disabled_element_set));
825 xbt_swag_remove(&elem, &(elem.constraint->active_element_set));
827 elem.decrease_concurrency();
830 var->sharing_weight = 0.0;
831 var->staged_weight = 0.0;
836 /* /brief Find variables that can be enabled and enable them.
838 * Assuming that the variable has already been removed from non-zero weights
839 * Can we find a staged variable to add?
840 * If yes, check that none of the constraints that this variable is involved in is at the limit of its concurrency
841 * And then add it to enabled variables
843 void s_lmm_system_t::on_disabled_var(lmm_constraint_t cnstr)
845 if (cnstr->get_concurrency_limit() < 0)
848 int numelem = xbt_swag_size(&(cnstr->disabled_element_set));
852 lmm_element_t elem = (lmm_element_t)xbt_swag_getFirst(&(cnstr->disabled_element_set));
854 // Cannot use xbt_swag_foreach, because lmm_enable_var will modify disabled_element_set.. within the loop
855 while (numelem-- && elem) {
857 lmm_element_t nextelem = (lmm_element_t)xbt_swag_getNext(elem, cnstr->disabled_element_set.offset);
859 if (elem->variable->staged_weight > 0 && elem->variable->can_enable()) {
860 // Found a staged variable
861 // TODOLATER: Add random timing function to model reservation protocol fuzziness? Then how to make sure that
862 // staged variables will eventually be called?
863 enable_var(elem->variable);
866 xbt_assert(cnstr->concurrency_current <= cnstr->get_concurrency_limit(), "Concurrency overflow!");
867 if (cnstr->concurrency_current == cnstr->get_concurrency_limit())
873 // We could get an assertion fail, because transiently there can be variables that are staged and could be activated.
874 // And we need to go through all constraints of the disabled var before getting back a coherent state.
875 // Anyway, caller functions all call check_concurrency() in the end.
878 /* \brief update the weight of a variable, and enable/disable it.
879 * @return Returns whether a change was made
881 void s_lmm_system_t::update_variable_weight(lmm_variable_t var, double weight)
883 xbt_assert(weight >= 0, "Variable weight should not be negative!");
885 if (weight == var->sharing_weight)
888 int enabling_var = (weight > 0 && var->sharing_weight <= 0);
889 int disabling_var = (weight <= 0 && var->sharing_weight > 0);
891 XBT_IN("(sys=%p, var=%p, weight=%f)", this, var, weight);
895 // Are we enabling this variable?
897 var->staged_weight = weight;
898 int minslack = var->get_min_concurrency_slack();
899 if (minslack < var->concurrency_share) {
900 XBT_DEBUG("Staging var (instead of enabling) because min concurrency slack %i, with weight %f and concurrency"
902 minslack, weight, var->concurrency_share);
905 XBT_DEBUG("Enabling var with min concurrency slack %i", minslack);
907 } else if (disabling_var) {
908 // Are we disabling this variable?
911 var->sharing_weight = weight;
919 void s_lmm_system_t::update_constraint_bound(lmm_constraint_t cnst, double bound)
922 update_modified_set(cnst);
926 /** \brief Update the constraint set propagating recursively to other constraints so the system should not be entirely
929 * \param sys the lmm_system_t
930 * \param cnst the lmm_constraint_t affected by the change
932 * A recursive algorithm to optimize the system recalculation selecting only constraints that have changed. Each
933 * constraint change is propagated to the list of constraints for each variable.
935 void s_lmm_system_t::update_modified_set_rec(lmm_constraint_t cnst)
939 xbt_swag_foreach(_elem, &cnst->enabled_element_set)
941 lmm_variable_t var = ((lmm_element_t)_elem)->variable;
942 for (s_lmm_element_t const& elem : var->cnsts) {
943 if (var->visited == visited_counter)
945 if (elem.constraint != cnst && not elem.constraint->modified_constraint_set_hook.is_linked()) {
946 modified_constraint_set.push_back(*elem.constraint);
947 update_modified_set_rec(elem.constraint);
950 // var will be ignored in later visits as long as sys->visited_counter does not move
951 var->visited = visited_counter;
955 void s_lmm_system_t::update_modified_set(lmm_constraint_t cnst)
957 /* nothing to do if selective update isn't active */
958 if (selective_update_active && not cnst->modified_constraint_set_hook.is_linked()) {
959 modified_constraint_set.push_back(*cnst);
960 update_modified_set_rec(cnst);
964 void s_lmm_system_t::remove_all_modified_set()
966 // We cleverly un-flag all variables just by incrementing visited_counter
967 // In effect, the var->visited value will no more be equal to visited counter
968 // To be clean, when visited counter has wrapped around, we force these var->visited values so that variables that
969 // were in the modified a long long time ago are not wrongly skipped here, which would lead to very nasty bugs
970 // (i.e. not readibily reproducible, and requiring a lot of run time before happening).
971 if (++visited_counter == 1) {
972 /* the counter wrapped around, reset each variable->visited */
974 xbt_swag_foreach(_var, &variable_set)((lmm_variable_t)_var)->visited = 0;
976 modified_constraint_set.clear();
980 * Returns resource load (in flop per second, or byte per second, or similar)
982 * If the resource is shared (the default case), the load is sum of resource usage made by every variables located on
985 * If the resource is not shared (ie in FATPIPE mode), then the load is the max (not the sum) of all resource usages
986 * located on this resource.
988 * \param cnst the lmm_constraint_t associated to the resource
990 double s_lmm_constraint_t::get_usage() const
993 const_xbt_swag_t elem_list = &enabled_element_set;
996 xbt_swag_foreach(_elem, elem_list)
998 lmm_element_t elem = (lmm_element_t)_elem;
999 if (elem->consumption_weight > 0) {
1001 result += elem->consumption_weight * elem->variable->value;
1002 else if (result < elem->consumption_weight * elem->variable->value)
1003 result = std::max(result, elem->consumption_weight * elem->variable->value);
1009 int s_lmm_constraint_t::get_variable_amount() const
1012 const_xbt_swag_t elem_list = &enabled_element_set;
1015 xbt_swag_foreach(_elem, elem_list)
1017 lmm_element_t elem = (lmm_element_t)_elem;
1018 if (elem->consumption_weight > 0)