src/mc/mc_dpor.c

   1 /* Copyright (c) 2008-2012. Da SimGrid Team. All rights reserved.           */
   2
   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. */
   5
   6 #include "mc_private.h"
   7
   8 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_dpor, mc,
   9                                 "Logging specific to MC DPOR exploration");
  10
  11 xbt_dynar_t visited_states;
  12
  13 static int is_visited_state(void);
  14 static void visited_state_free(mc_safety_visited_state_t state);
  15 static void visited_state_free_voidp(void *s);
  16
  17 static void visited_state_free(mc_safety_visited_state_t state){
  18   if(state){
  19     MC_free_snapshot(state->system_state);
  20     xbt_free(state);
  21   }
  22 }
  23
  24 static void visited_state_free_voidp(void *s){
  25   visited_state_free((mc_safety_visited_state_t) * (void **) s);
  26 }
  27
  28 static int is_visited_state(){
  29
  30   if(_sg_mc_visited == 0)
  31     return 0;
  32
  33   int raw_mem_set = (mmalloc_get_current_heap() == raw_heap);
  34
  35   MC_SET_RAW_MEM;
  36
  37   mc_safety_visited_state_t new_state = NULL;
  38   new_state = xbt_new0(s_mc_safety_visited_state_t, 1);
  39   new_state->system_state = MC_take_snapshot();
  40   new_state->num = mc_stats->expanded_states;
  41
  42   MC_UNSET_RAW_MEM;
  43
  44   if(xbt_dynar_is_empty(visited_states)){
  45
  46     MC_SET_RAW_MEM;
  47     xbt_dynar_push(visited_states, &new_state);
  48     MC_UNSET_RAW_MEM;
  49
  50     if(raw_mem_set)
  51       MC_SET_RAW_MEM;
  52
  53     return -1;
  54
  55   }else{
  56
  57     MC_SET_RAW_MEM;
  58
  59     size_t current_bytes_used = new_state->system_state->heap_bytes_used;
  60
  61     unsigned int cursor = 0;
  62     int previous_cursor = 0, next_cursor = 0;
  63     int start = 0;
  64     int end = xbt_dynar_length(visited_states) - 1;
  65
  66     mc_safety_visited_state_t state_test = NULL;
  67     size_t bytes_used_test;
  68     int same_bytes_not_found = 1;
  69
  70     while(start <= end && same_bytes_not_found){
  71       cursor = (start + end) / 2;
  72       state_test = (mc_safety_visited_state_t)xbt_dynar_get_as(visited_states, cursor, mc_safety_visited_state_t);
  73       bytes_used_test = state_test->system_state->heap_bytes_used;
  74       if(bytes_used_test < current_bytes_used)
  75         start = cursor + 1;
  76       if(bytes_used_test > current_bytes_used)
  77         end = cursor - 1;
  78       if(bytes_used_test == current_bytes_used){
  79         same_bytes_not_found = 0;
  80         if(snapshot_compare(new_state->system_state, state_test->system_state) == 0){
  81           xbt_dynar_remove_at(visited_states, cursor, NULL);
  82           xbt_dynar_insert_at(visited_states, cursor, &new_state);
  83           XBT_DEBUG("State %d already visited ! (equal to state %d)", new_state->num, state_test->num);
  84           if(raw_mem_set)
  85             MC_SET_RAW_MEM;
  86           else
  87             MC_UNSET_RAW_MEM;
  88           return state_test->num;
  89         }else{
  90           /* Search another state with same number of bytes used */
  91           previous_cursor = cursor - 1;
  92           while(previous_cursor >= 0){
  93             state_test = (mc_safety_visited_state_t)xbt_dynar_get_as(visited_states, previous_cursor, mc_safety_visited_state_t);
  94             bytes_used_test = state_test->system_state->heap_bytes_used;
  95             if(bytes_used_test != current_bytes_used)
  96               break;
  97             if(snapshot_compare(new_state->system_state, state_test->system_state) == 0){
  98               xbt_dynar_remove_at(visited_states, previous_cursor, NULL);
  99               xbt_dynar_insert_at(visited_states, previous_cursor, &new_state);
 100               XBT_DEBUG("State %d already visited ! (equal to state %d)", new_state->num, state_test->num);
 101               if(raw_mem_set)
 102                 MC_SET_RAW_MEM;
 103               else
 104                 MC_UNSET_RAW_MEM;
 105               return state_test->num;
 106             }
 107             previous_cursor--;
 108           }
 109           next_cursor = cursor + 1;
 110           while(next_cursor < xbt_dynar_length(visited_states)){
 111             state_test = (mc_safety_visited_state_t)xbt_dynar_get_as(visited_states, next_cursor, mc_safety_visited_state_t);
 112             bytes_used_test = state_test->system_state->heap_bytes_used;
 113             if(bytes_used_test != current_bytes_used)
 114               break;
 115             if(snapshot_compare(new_state->system_state, state_test->system_state) == 0){
 116               xbt_dynar_remove_at(visited_states, next_cursor, NULL);
 117               xbt_dynar_insert_at(visited_states, next_cursor, &new_state);
 118               XBT_DEBUG("State %d already visited ! (equal to state %d)", new_state->num, state_test->num);
 119               if(raw_mem_set)
 120                 MC_SET_RAW_MEM;
 121               else
 122                 MC_UNSET_RAW_MEM;
 123               return state_test->num;
 124             }
 125             next_cursor++;
 126           }
 127         }
 128       }
 129     }
 130
 131     state_test = (mc_safety_visited_state_t)xbt_dynar_get_as(visited_states, cursor, mc_safety_visited_state_t);
 132     bytes_used_test = state_test->system_state->heap_bytes_used;
 133
 134     if(bytes_used_test < current_bytes_used)
 135       xbt_dynar_insert_at(visited_states, cursor + 1, &new_state);
 136     else
 137       xbt_dynar_insert_at(visited_states, cursor, &new_state);
 138
 139     if(xbt_dynar_length(visited_states) > _sg_mc_visited){
 140       int min = mc_stats->expanded_states;
 141       unsigned int cursor2 = 0;
 142       unsigned int index = 0;
 143       xbt_dynar_foreach(visited_states, cursor2, state_test){
 144         if(state_test->num < min){
 145           index = cursor2;
 146           min = state_test->num;
 147         }
 148       }
 149       xbt_dynar_remove_at(visited_states, index, NULL);
 150     }
 151
 152     MC_UNSET_RAW_MEM;
 153
 154     if(raw_mem_set)
 155       MC_SET_RAW_MEM;
 156
 157     return -1;
 158
 159   }
 160 }
 161
 162 /**
 163  *  \brief Initialize the DPOR exploration algorithm
 164  */
 165 void MC_dpor_init()
 166 {
 167
 168   int raw_mem_set = (mmalloc_get_current_heap() == raw_heap);
 169
 170   mc_state_t initial_state = NULL;
 171   smx_process_t process;
 172
 173   /* Create the initial state and push it into the exploration stack */
 174   MC_SET_RAW_MEM;
 175
 176   initial_state = MC_state_new();
 177   visited_states = xbt_dynar_new(sizeof(mc_safety_visited_state_t), visited_state_free_voidp);
 178
 179   MC_UNSET_RAW_MEM;
 180
 181   XBT_DEBUG("**************************************************");
 182   XBT_DEBUG("Initial state");
 183
 184   /* Wait for requests (schedules processes) */
 185   MC_wait_for_requests();
 186
 187   MC_SET_RAW_MEM;
 188
 189   /* Get an enabled process and insert it in the interleave set of the initial state */
 190   xbt_swag_foreach(process, simix_global->process_list){
 191     if(MC_process_is_enabled(process)){
 192       MC_state_interleave_process(initial_state, process);
 193       XBT_DEBUG("Process %lu enabled with simcall %d", process->pid, process->simcall.call);
 194     }
 195   }
 196
 197   xbt_fifo_unshift(mc_stack_safety, initial_state);
 198
 199   MC_UNSET_RAW_MEM;
 200
 201   if(raw_mem_set)
 202     MC_SET_RAW_MEM;
 203   else
 204     MC_UNSET_RAW_MEM;
 205
 206 }
 207
 208
 209 /**
 210  *   \brief Perform the model-checking operation using a depth-first search exploration
 211  *         with Dynamic Partial Order Reductions
 212  */
 213 void MC_dpor(void)
 214 {
 215
 216   char *req_str;
 217   int value, value2;
 218   smx_simcall_t req = NULL, prev_req = NULL, req2 = NULL;
 219   s_smx_simcall_t req3;
 220   mc_state_t state = NULL, prev_state = NULL, next_state = NULL, restore_state=NULL;
 221   smx_process_t process = NULL;
 222   xbt_fifo_item_t item = NULL;
 223   int pos, i, interleave_size;
 224   int interleave_proc[simix_process_maxpid];
 225   int visited_state;
 226
 227   while (xbt_fifo_size(mc_stack_safety) > 0) {
 228
 229     /* Get current state */
 230     state = (mc_state_t)
 231       xbt_fifo_get_item_content(xbt_fifo_get_first_item(mc_stack_safety));
 232
 233     XBT_DEBUG("**************************************************");
 234     XBT_DEBUG("Exploration depth=%d (state=%p)(%u interleave)",
 235               xbt_fifo_size(mc_stack_safety), state,
 236               MC_state_interleave_size(state));
 237
 238     /* Update statistics */
 239     mc_stats->visited_states++;
 240
 241     /* If there are processes to interleave and the maximum depth has not been reached
 242        then perform one step of the exploration algorithm */
 243     if (xbt_fifo_size(mc_stack_safety) < _sg_mc_max_depth &&
 244         (req = MC_state_get_request(state, &value))) {
 245
 246       /* Debug information */
 247       if(XBT_LOG_ISENABLED(mc_dpor, xbt_log_priority_debug)){
 248         req_str = MC_request_to_string(req, value);
 249         XBT_DEBUG("Execute: %s", req_str);
 250         xbt_free(req_str);
 251       }
 252
 253       MC_state_set_executed_request(state, req, value);
 254       mc_stats->executed_transitions++;
 255
 256       if(MC_state_interleave_size(state)){
 257         MC_SET_RAW_MEM;
 258         req2 = MC_state_get_internal_request(state);
 259         req3 = *req2;
 260         for(i=0; i<simix_process_maxpid; i++)
 261           interleave_proc[i] = 0;
 262         i=0;
 263         interleave_size = MC_state_interleave_size(state);
 264         while(i < interleave_size){
 265           i++;
 266           prev_req = MC_state_get_request(state, &value2);
 267           if(prev_req != NULL){
 268             MC_state_set_executed_request(state, prev_req, value2);
 269             prev_req = MC_state_get_internal_request(state);
 270             if(MC_request_depend(&req3, prev_req)){
 271               XBT_DEBUG("Simcall %d in process %lu dependant with simcall %d in process %lu", req3.call, req3.issuer->pid, prev_req->call, prev_req->issuer->pid);
 272               interleave_proc[prev_req->issuer->pid] = 1;
 273             }else{
 274               XBT_DEBUG("Simcall %d in process %lu independant with simcall %d in process %lu", req3.call, req3.issuer->pid, prev_req->call, prev_req->issuer->pid);
 275               MC_state_remove_interleave_process(state, prev_req->issuer);
 276             }
 277           }
 278         }
 279         xbt_swag_foreach(process, simix_global->process_list){
 280           if(interleave_proc[process->pid] == 1)
 281             MC_state_interleave_process(state, process);
 282         }
 283         MC_UNSET_RAW_MEM;
 284       }
 285
 286       MC_state_set_executed_request(state, req, value);
 287
 288       /* Answer the request */
 289       SIMIX_simcall_pre(req, value); /* After this call req is no longer usefull */
 290
 291       /* Wait for requests (schedules processes) */
 292       MC_wait_for_requests();
 293
 294       /* Create the new expanded state */
 295       MC_SET_RAW_MEM;
 296
 297       next_state = MC_state_new();
 298
 299       if((visited_state = is_visited_state()) == -1){
 300
 301         /* Get an enabled process and insert it in the interleave set of the next state */
 302         xbt_swag_foreach(process, simix_global->process_list){
 303           if(MC_process_is_enabled(process)){
 304             MC_state_interleave_process(next_state, process);
 305             XBT_DEBUG("Process %lu enabled with simcall %d", process->pid, process->simcall.call);
 306           }
 307         }
 308
 309         if(_sg_mc_checkpoint && ((xbt_fifo_size(mc_stack_safety) + 1) % _sg_mc_checkpoint == 0)){
 310           next_state->system_state = MC_take_snapshot();
 311         }
 312
 313       }
 314
 315       xbt_fifo_unshift(mc_stack_safety, next_state);
 316       MC_UNSET_RAW_MEM;
 317
 318       /* Let's loop again */
 319
 320       /* The interleave set is empty or the maximum depth is reached, let's back-track */
 321     } else {
 322
 323       if(xbt_fifo_size(mc_stack_safety) == _sg_mc_max_depth)
 324         XBT_WARN("/!\\ Max depth reached ! /!\\ ");
 325       else
 326         XBT_DEBUG("There are no more processes to interleave.");
 327
 328       /* Trash the current state, no longer needed */
 329       MC_SET_RAW_MEM;
 330       xbt_fifo_shift(mc_stack_safety);
 331       MC_state_delete(state);
 332       MC_UNSET_RAW_MEM;
 333
 334       /* Check for deadlocks */
 335       if(MC_deadlock_check()){
 336         MC_show_deadlock(NULL);
 337         return;
 338       }
 339
 340       MC_SET_RAW_MEM;
 341       /* Traverse the stack backwards until a state with a non empty interleave
 342          set is found, deleting all the states that have it empty in the way.
 343          For each deleted state, check if the request that has generated it
 344          (from it's predecesor state), depends on any other previous request
 345          executed before it. If it does then add it to the interleave set of the
 346          state that executed that previous request. */
 347
 348       while ((state = xbt_fifo_shift(mc_stack_safety)) != NULL) {
 349         req = MC_state_get_internal_request(state);
 350         xbt_fifo_foreach(mc_stack_safety, item, prev_state, mc_state_t) {
 351           if(MC_request_depend(req, MC_state_get_internal_request(prev_state))){
 352             if(XBT_LOG_ISENABLED(mc_dpor, xbt_log_priority_debug)){
 353               XBT_DEBUG("Dependent Transitions:");
 354               prev_req = MC_state_get_executed_request(prev_state, &value);
 355               req_str = MC_request_to_string(prev_req, value);
 356               XBT_DEBUG("%s (state=%p)", req_str, prev_state);
 357               xbt_free(req_str);
 358               prev_req = MC_state_get_executed_request(state, &value);
 359               req_str = MC_request_to_string(prev_req, value);
 360               XBT_DEBUG("%s (state=%p)", req_str, state);
 361               xbt_free(req_str);
 362             }
 363
 364             break;
 365
 366           }else if(req->issuer == MC_state_get_internal_request(prev_state)->issuer){
 367
 368             XBT_DEBUG("Simcall %d and %d with same issuer", req->call, MC_state_get_internal_request(prev_state)->call);
 369             break;
 370
 371           }else{
 372
 373             MC_state_remove_interleave_process(prev_state, req->issuer);
 374             XBT_DEBUG("Simcall %d in process %lu independant with simcall %d process %lu", req->call, req->issuer->pid, MC_state_get_internal_request(prev_state)->call, MC_state_get_internal_request(prev_state)->issuer->pid);
 375
 376           }
 377         }
 378
 379         if (MC_state_interleave_size(state)) {
 380           /* We found a back-tracking point, let's loop */
 381           if(_sg_mc_checkpoint){
 382             if(state->system_state != NULL){
 383               MC_restore_snapshot(state->system_state);
 384               xbt_fifo_unshift(mc_stack_safety, state);
 385               MC_UNSET_RAW_MEM;
 386             }else{
 387               pos = xbt_fifo_size(mc_stack_safety);
 388               item = xbt_fifo_get_first_item(mc_stack_safety);
 389               while(pos>0){
 390                 restore_state = (mc_state_t) xbt_fifo_get_item_content(item);
 391                 if(restore_state->system_state != NULL){
 392                   break;
 393                 }else{
 394                   item = xbt_fifo_get_next_item(item);
 395                   pos--;
 396                 }
 397               }
 398               MC_restore_snapshot(restore_state->system_state);
 399               xbt_fifo_unshift(mc_stack_safety, state);
 400               MC_UNSET_RAW_MEM;
 401               MC_replay(mc_stack_safety, pos);
 402             }
 403           }else{
 404             xbt_fifo_unshift(mc_stack_safety, state);
 405             MC_UNSET_RAW_MEM;
 406             MC_replay(mc_stack_safety, -1);
 407           }
 408           XBT_DEBUG("Back-tracking to depth %d", xbt_fifo_size(mc_stack_safety));
 409           break;
 410         } else {
 411           MC_state_delete(state);
 412         }
 413       }
 414       MC_UNSET_RAW_MEM;
 415     }
 416   }
 417   MC_print_statistics(mc_stats);
 418   MC_UNSET_RAW_MEM;
 419
 420   return;
 421 }
 422
 423
 424
 425