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