src/mc/mc_visited.cpp

   1 /* Copyright (c) 2011-2015. The SimGrid Team.
   2  * All rights reserved.                                                     */
   3
   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. */
   6
   7 #include <unistd.h>
   8 #include <sys/wait.h>
   9
  10 #include <memory>
  11 #include <algorithm>
  12
  13 #include <xbt/automaton.h>
  14 #include <xbt/log.h>
  15 #include <xbt/sysdep.h>
  16 #include <xbt/dynar.h>
  17 #include <xbt/dynar.hpp>
  18 #include <xbt/fifo.h>
  19
  20 #include "src/mc/mc_comm_pattern.h"
  21 #include "src/mc/mc_safety.h"
  22 #include "src/mc/LivenessChecker.hpp"
  23 #include "src/mc/mc_private.h"
  24 #include "src/mc/Process.hpp"
  25 #include "src/mc/mc_smx.h"
  26
  27 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_visited, mc,
  28                                 "Logging specific to state equaity detection mechanisms");
  29
  30 namespace simgrid {
  31 namespace mc {
  32
  33 std::vector<std::unique_ptr<simgrid::mc::VisitedState>> visited_states;
  34
  35 static int is_exploration_stack_state(simgrid::mc::VisitedState* state){
  36   xbt_fifo_item_t item = xbt_fifo_get_first_item(mc_stack);
  37   while (item) {
  38     if (((simgrid::mc::State*)xbt_fifo_get_item_content(item))->num == state->num){
  39       ((simgrid::mc::State*)xbt_fifo_get_item_content(item))->in_visited_states = 0;
  40       return 1;
  41     }
  42     item = xbt_fifo_get_next_item(item);
  43   }
  44   return 0;
  45 }
  46
  47 /**
  48  * \brief Save the current state
  49  * \return Snapshot of the current state.
  50  */
  51 VisitedState::VisitedState()
  52 {
  53   simgrid::mc::Process* process = &(mc_model_checker->process());
  54   this->heap_bytes_used = mmalloc_get_bytes_used_remote(
  55     process->get_heap()->heaplimit,
  56     process->get_malloc_info());
  57
  58   this->nb_processes =
  59     mc_model_checker->process().simix_processes().size();
  60
  61   this->system_state = simgrid::mc::take_snapshot(mc_stats->expanded_states);
  62   this->num = mc_stats->expanded_states;
  63   this->other_num = -1;
  64 }
  65
  66 VisitedState::~VisitedState()
  67 {
  68   if(!is_exploration_stack_state(this))
  69     delete this->system_state;
  70 }
  71
  72 static void prune_visited_states()
  73 {
  74   while (visited_states.size() > (std::size_t) _sg_mc_visited) {
  75     XBT_DEBUG("Try to remove visited state (maximum number of stored states reached)");
  76     auto min_element = std::min_element(visited_states.begin(), visited_states.end(),
  77       [](std::unique_ptr<simgrid::mc::VisitedState>& a, std::unique_ptr<simgrid::mc::VisitedState>& b) {
  78         return a->num < b->num;
  79       });
  80     xbt_assert(min_element != visited_states.end());
  81     // and drop it:
  82     visited_states.erase(min_element);
  83     XBT_DEBUG("Remove visited state (maximum number of stored states reached)");
  84   }
  85 }
  86
  87 static int snapshot_compare(simgrid::mc::VisitedState* state1, simgrid::mc::VisitedState* state2)
  88 {
  89   simgrid::mc::Snapshot* s1 = state1->system_state;
  90   simgrid::mc::Snapshot* s2 = state2->system_state;
  91   int num1 = state1->num;
  92   int num2 = state2->num;
  93   return snapshot_compare(num1, s1, num2, s2);
  94 }
  95
  96 /**
  97  * \brief Checks whether a given state has already been visited by the algorithm.
  98  */
  99 std::unique_ptr<simgrid::mc::VisitedState> is_visited_state(simgrid::mc::State* graph_state, bool compare_snpashots)
 100 {
 101
 102
 103   std::unique_ptr<simgrid::mc::VisitedState> new_state =
 104     std::unique_ptr<simgrid::mc::VisitedState>(new VisitedState());
 105   graph_state->system_state = new_state->system_state;
 106   graph_state->in_visited_states = 1;
 107   XBT_DEBUG("Snapshot %p of visited state %d (exploration stack state %d)", new_state->system_state, new_state->num, graph_state->num);
 108
 109   auto range = std::equal_range(visited_states.begin(), visited_states.end(),
 110     new_state.get(), simgrid::mc::DerefAndCompareByNbProcessesAndUsedHeap());
 111
 112       if (compare_snpashots) {
 113
 114         for (auto i = range.first; i != range.second; ++i) {
 115           auto& visited_state = *i;
 116           if (snapshot_compare(visited_state.get(), new_state.get()) == 0) {
 117             // The state has been visited:
 118
 119             std::unique_ptr<simgrid::mc::VisitedState> old_state =
 120               std::move(visited_state);
 121
 122             if (old_state->other_num == -1)
 123               new_state->other_num = old_state->num;
 124             else
 125               new_state->other_num = old_state->other_num;
 126
 127             if (dot_output == nullptr)
 128               XBT_DEBUG("State %d already visited ! (equal to state %d)",
 129                 new_state->num, old_state->num);
 130             else
 131               XBT_DEBUG(
 132                 "State %d already visited ! (equal to state %d (state %d in dot_output))",
 133                 new_state->num, old_state->num, new_state->other_num);
 134
 135             /* Replace the old state with the new one (with a bigger num)
 136                (when the max number of visited states is reached,  the oldest
 137                one is removed according to its number (= with the min number) */
 138             XBT_DEBUG("Replace visited state %d with the new visited state %d",
 139               old_state->num, new_state->num);
 140
 141             visited_state = std::move(new_state);
 142             return std::move(old_state);
 143           }
 144         }
 145       }
 146
 147   XBT_DEBUG("Insert new visited state %d (total : %lu)", new_state->num, (unsigned long) visited_states.size());
 148   visited_states.insert(range.first, std::move(new_state));
 149   prune_visited_states();
 150   return nullptr;
 151 }
 152
 153 }
 154 }