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