1 /* Copyright (c) 2008 Martin Quinson, Cristian Rosa.
2 All rights reserved. */
4 /* This program is free software; you can redistribute it and/or modify it
5 * under the terms of the license (GNU LGPL) which comes with this package. */
9 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_dpor, mc,
10 "Logging specific to MC DPOR exploration");
13 * \brief Initialize the DPOR exploration algorithm
17 mc_state_t initial_state = NULL;
18 mc_transition_t trans = NULL;
20 /* Create the initial state and push it into the exploration stack */
22 initial_state = MC_state_new();
23 xbt_fifo_unshift(mc_stack, initial_state);
26 /* Schedule all the processes to detect the transitions of the initial state */
27 DEBUG0("**************************************************");
28 DEBUG0("Initial state");
29 MC_schedule_enabled_processes();
32 MC_trans_compute_enabled(initial_state->enabled_transitions,
33 initial_state->transitions);
35 /* Fill the interleave set of the initial state with an enabled process */
36 trans = xbt_setset_set_choose(initial_state->enabled_transitions);
38 xbt_setset_set_insert(initial_state->interleave, trans);
41 /* Update Statistics */
42 mc_stats->state_size += xbt_setset_set_size(initial_state->enabled_transitions);
47 * \brief Perform the model-checking operation using a depth-first search exploration
48 * with Dynamic Partial Order Reductions
52 mc_transition_t trans = NULL;
53 mc_state_t next_state = NULL;
54 xbt_setset_cursor_t cursor = NULL;
56 while(xbt_fifo_size(mc_stack) > 0){
58 DEBUG0("**************************************************");
60 /* FIXME: Think about what happen if there are no transitions but there are
61 some actions on the models. (ex. all the processes do a sleep(0) in a round). */
63 /* Get current state */
64 mc_current_state = (mc_state_t) xbt_fifo_get_item_content(xbt_fifo_get_first_item(mc_stack));
66 /* If there are transitions to execute and the maximun depth has not been reached
67 then perform one step of the exploration algorithm */
68 if(xbt_setset_set_size(mc_current_state->interleave) > 0 && xbt_fifo_size(mc_stack) < MAX_DEPTH){
70 DEBUG4("Exploration detph=%d (state=%p)(%d interleave) (%d enabled)", xbt_fifo_size(mc_stack),
71 mc_current_state, xbt_setset_set_size(mc_current_state->interleave),
72 xbt_setset_set_size(mc_current_state->enabled_transitions));
74 xbt_setset_foreach(mc_current_state->enabled_transitions, cursor, trans){
75 DEBUG1("\t %s", trans->name);
78 /* Update statistics */
79 mc_stats->visited_states++;
80 mc_stats->executed_transitions++;
82 /* Choose a transition to execute from the interleave set of the current
83 state, and create the data structures for the new expanded state in the
86 trans = xbt_setset_set_choose(mc_current_state->interleave);
87 if(!trans->type == mc_random){
88 xbt_setset_set_remove(mc_current_state->interleave, trans);
89 /* Add the transition in the done set of the current state */
90 xbt_setset_set_insert(mc_current_state->done, trans);
93 next_state = MC_state_new();
94 xbt_fifo_unshift(mc_stack, next_state);
96 /* Set it as the executed transition of the current state */
97 mc_current_state->executed_transition = trans;
100 /* Execute the selected transition by scheduling it's associated process.
101 Then schedule every process that got ready to run due to the execution
103 DEBUG1("Executing transition %s", trans->name);
104 SIMIX_process_schedule(trans->process);
105 MC_execute_surf_actions(); /* Do surf's related black magic */
106 MC_schedule_enabled_processes();
108 if(trans->type == mc_random && trans->random.current_value < trans->random.max){
109 trans->random.current_value++;
111 trans->random.current_value = trans->random.min;
112 xbt_setset_set_remove(mc_current_state->interleave, trans);
113 xbt_setset_set_insert(mc_current_state->done, trans);
116 /* Calculate the enabled transitions set of the next state */
118 xbt_setset_add(next_state->transitions, mc_current_state->transitions);
119 xbt_setset_set_remove(next_state->transitions, trans);
120 MC_trans_compute_enabled(next_state->enabled_transitions, next_state->transitions);
122 /* Choose one transition to interleave from the enabled transition set */
123 trans = xbt_setset_set_choose(next_state->enabled_transitions);
125 xbt_setset_set_insert(next_state->interleave, trans);
128 /* Update Statistics */
129 mc_stats->state_size += xbt_setset_set_size(next_state->enabled_transitions);
131 /* Let's loop again */
133 /* The interleave set is empty or the maximum depth is reached, let's back-track */
135 DEBUG0("There are no more transitions to interleave.");
138 /* Check for deadlocks */
139 xbt_setset_substract(mc_current_state->transitions, mc_current_state->done);
140 if(xbt_setset_set_size(mc_current_state->transitions) > 0){
141 INFO0("**************************");
142 INFO0("*** DEAD-LOCK DETECTED ***");
143 INFO0("**************************");
144 INFO0("Counter-example execution trace:");
145 MC_dump_stack(mc_stack);
146 MC_print_statistics(mc_stats);
150 mc_transition_t q = NULL;
151 xbt_fifo_item_t item = NULL;
152 mc_state_t state = NULL;
154 //MC_show_stack(mc_stack);
156 /* Trash the current state, no longer needed */
158 xbt_fifo_shift(mc_stack);
159 MC_state_delete(mc_current_state);
161 /* Traverse the stack backwards until a state with a non empty interleave
162 set is found, deleting all the states that have it empty in the way.
163 For each deleted state, check if the transition that has generated it
164 (from it's predecesor state), depends on any other previous transition
165 executed before it. If it does then add it to the interleave set of the
166 state that executed that previous transition. */
167 while((mc_current_state = xbt_fifo_shift(mc_stack)) != NULL){
168 q = mc_current_state->executed_transition;
169 xbt_fifo_foreach(mc_stack, item, state, mc_state_t){
170 if(MC_transition_depend(q, state->executed_transition)){
171 DEBUG3("Dependence found at state %p (%p,%p)", state, state->executed_transition, q);
172 xbt_setset_foreach(state->enabled_transitions, cursor, trans){
173 if((trans->process == q->process) && !xbt_setset_set_belongs(state->done, trans)){
174 DEBUG2("Unexplored interleaving found at state %p (%p)", state, trans);
175 xbt_setset_set_insert(state->interleave, trans);
183 if(xbt_setset_set_size(mc_current_state->interleave) > 0){
184 /* We found a back-tracking point, let's loop */
185 xbt_fifo_unshift(mc_stack, mc_current_state);
186 DEBUG1("Back-tracking to depth %d", xbt_fifo_size(mc_stack));
191 MC_state_delete(mc_current_state);
196 DEBUG0("We are done");
197 /* We are done, show the statistics and return */
198 MC_print_statistics(mc_stats);