src/mc/mc_dpor.c

   1 /* Copyright (c) 2008-2013. 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_visited_state_t state);
  15 static void visited_state_free_voidp(void *s);
  16
  17 static void visited_state_free(mc_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_visited_state_t) * (void **) s);
  26 }
  27
  28 static int is_visited_state(){
  29
  30   if(_sg_mc_visited == 0)
  31     return -1;
  32
  33   int raw_mem_set = (mmalloc_get_current_heap() == raw_heap);
  34
  35   MC_SET_RAW_MEM;
  36
  37   mc_visited_state_t new_state = NULL;
  38   new_state = xbt_new0(s_mc_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_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_visited_state_t)xbt_dynar_get_as(visited_states, cursor, mc_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_visited_state_t)xbt_dynar_get_as(visited_states, previous_cursor, mc_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_visited_state_t)xbt_dynar_get_as(visited_states, next_cursor, mc_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_visited_state_t)xbt_dynar_get_as(visited_states, cursor, mc_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_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       req_str = MC_request_get_dot_output(req, value);
 254
 255       MC_state_set_executed_request(state, req, value);
 256       mc_stats->executed_transitions++;
 257
 258       if(MC_state_interleave_size(state)){
 259         MC_SET_RAW_MEM;
 260         req2 = MC_state_get_internal_request(state);
 261         req3 = *req2;
 262         for(i=0; i<simix_process_maxpid; i++)
 263           interleave_proc[i] = 0;
 264         i=0;
 265         interleave_size = MC_state_interleave_size(state);
 266         while(i < interleave_size){
 267           i++;
 268           prev_req = MC_state_get_request(state, &value2);
 269           if(prev_req != NULL){
 270             MC_state_set_executed_request(state, prev_req, value2);
 271             prev_req = MC_state_get_internal_request(state);
 272             if(MC_request_depend(&req3, prev_req)){
 273               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);
 274               interleave_proc[prev_req->issuer->pid] = 1;
 275             }else{
 276               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);
 277               MC_state_remove_interleave_process(state, prev_req->issuer);
 278             }
 279           }
 280         }
 281         xbt_swag_foreach(process, simix_global->process_list){
 282           if(interleave_proc[process->pid] == 1)
 283             MC_state_interleave_process(state, process);
 284         }
 285         MC_UNSET_RAW_MEM;
 286       }
 287
 288       MC_state_set_executed_request(state, req, value);
 289
 290       /* Answer the request */
 291       SIMIX_simcall_pre(req, value); /* After this call req is no longer usefull */
 292
 293       /* Wait for requests (schedules processes) */
 294       MC_wait_for_requests();
 295
 296       /* Create the new expanded state */
 297       MC_SET_RAW_MEM;
 298
 299       next_state = MC_state_new();
 300
 301       if((visited_state = is_visited_state()) == -1){
 302
 303         /* Get an enabled process and insert it in the interleave set of the next state */
 304         xbt_swag_foreach(process, simix_global->process_list){
 305           if(MC_process_is_enabled(process)){
 306             MC_state_interleave_process(next_state, process);
 307             XBT_DEBUG("Process %lu enabled with simcall %d", process->pid, process->simcall.call);
 308           }
 309         }
 310
 311         if(_sg_mc_checkpoint && ((xbt_fifo_size(mc_stack_safety) + 1) % _sg_mc_checkpoint == 0)){
 312           next_state->system_state = MC_take_snapshot();
 313         }
 314
 315         if(dot_output != NULL)
 316           fprintf(dot_output, "\"%d\" -> \"%d\" [%s];\n", state->num, next_state->num, req_str);
 317
 318       }else{
 319
 320         if(dot_output != NULL)
 321           fprintf(dot_output, "\"%d\" -> \"%d\" [%s];\n", state->num, visited_state, req_str);
 322
 323       }
 324
 325       xbt_fifo_unshift(mc_stack_safety, next_state);
 326       MC_UNSET_RAW_MEM;
 327
 328       xbt_free(req_str);
 329
 330       /* Let's loop again */
 331
 332       /* The interleave set is empty or the maximum depth is reached, let's back-track */
 333     } else {
 334
 335       if(xbt_fifo_size(mc_stack_safety) == _sg_mc_max_depth)
 336         XBT_WARN("/!\\ Max depth reached ! /!\\ ");
 337       else
 338         XBT_DEBUG("There are no more processes to interleave.");
 339
 340       /* Trash the current state, no longer needed */
 341       MC_SET_RAW_MEM;
 342       xbt_fifo_shift(mc_stack_safety);
 343       MC_state_delete(state);
 344       MC_UNSET_RAW_MEM;
 345
 346       /* Check for deadlocks */
 347       if(MC_deadlock_check()){
 348         MC_show_deadlock(NULL);
 349         return;
 350       }
 351
 352       MC_SET_RAW_MEM;
 353       /* Traverse the stack backwards until a state with a non empty interleave
 354          set is found, deleting all the states that have it empty in the way.
 355          For each deleted state, check if the request that has generated it
 356          (from it's predecesor state), depends on any other previous request
 357          executed before it. If it does then add it to the interleave set of the
 358          state that executed that previous request. */
 359
 360       while ((state = xbt_fifo_shift(mc_stack_safety)) != NULL) {
 361         req = MC_state_get_internal_request(state);
 362         xbt_fifo_foreach(mc_stack_safety, item, prev_state, mc_state_t) {
 363           if(MC_request_depend(req, MC_state_get_internal_request(prev_state))){
 364             if(XBT_LOG_ISENABLED(mc_dpor, xbt_log_priority_debug)){
 365               XBT_DEBUG("Dependent Transitions:");
 366               prev_req = MC_state_get_executed_request(prev_state, &value);
 367               req_str = MC_request_to_string(prev_req, value);
 368               XBT_DEBUG("%s (state=%p)", req_str, prev_state);
 369               xbt_free(req_str);
 370               prev_req = MC_state_get_executed_request(state, &value);
 371               req_str = MC_request_to_string(prev_req, value);
 372               XBT_DEBUG("%s (state=%p)", req_str, state);
 373               xbt_free(req_str);
 374             }
 375
 376             break;
 377
 378           }else if(req->issuer == MC_state_get_internal_request(prev_state)->issuer){
 379
 380             XBT_DEBUG("Simcall %d and %d with same issuer", req->call, MC_state_get_internal_request(prev_state)->call);
 381             break;
 382
 383           }else{
 384
 385             MC_state_remove_interleave_process(prev_state, req->issuer);
 386             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);
 387
 388           }
 389         }
 390
 391         if (MC_state_interleave_size(state)) {
 392           /* We found a back-tracking point, let's loop */
 393           if(_sg_mc_checkpoint){
 394             if(state->system_state != NULL){
 395               MC_restore_snapshot(state->system_state);
 396               xbt_fifo_unshift(mc_stack_safety, state);
 397               MC_UNSET_RAW_MEM;
 398             }else{
 399               pos = xbt_fifo_size(mc_stack_safety);
 400               item = xbt_fifo_get_first_item(mc_stack_safety);
 401               while(pos>0){
 402                 restore_state = (mc_state_t) xbt_fifo_get_item_content(item);
 403                 if(restore_state->system_state != NULL){
 404                   break;
 405                 }else{
 406                   item = xbt_fifo_get_next_item(item);
 407                   pos--;
 408                 }
 409               }
 410               MC_restore_snapshot(restore_state->system_state);
 411               xbt_fifo_unshift(mc_stack_safety, state);
 412               MC_UNSET_RAW_MEM;
 413               MC_replay(mc_stack_safety, pos);
 414             }
 415           }else{
 416             xbt_fifo_unshift(mc_stack_safety, state);
 417             MC_UNSET_RAW_MEM;
 418             MC_replay(mc_stack_safety, -1);
 419           }
 420           XBT_DEBUG("Back-tracking to depth %d", xbt_fifo_size(mc_stack_safety));
 421           break;
 422         } else {
 423           MC_state_delete(state);
 424         }
 425       }
 426       MC_UNSET_RAW_MEM;
 427     }
 428   }
 429   MC_print_statistics(mc_stats);
 430   MC_UNSET_RAW_MEM;
 431
 432   return;
 433 }
 434
 435
 436
 437