src/instr/instr_platform.cpp

   1 /* Copyright (c) 2010-2018. The 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 "src/instr/instr_private.hpp"
   7
   8 #include "simgrid/kernel/routing/NetPoint.hpp"
   9 #include "simgrid/kernel/routing/NetZoneImpl.hpp"
  10 #include "simgrid/s4u/Actor.hpp"
  11 #include "simgrid/s4u/Engine.hpp"
  12 #include "simgrid/s4u/Host.hpp"
  13 #include "simgrid/s4u/VirtualMachine.hpp"
  14 #include "src/surf/cpu_interface.hpp"
  15 #include "src/surf/network_interface.hpp"
  16 #include "src/surf/surf_interface.hpp"
  17 #include "src/surf/xml/platf_private.hpp"
  18 #include "surf/surf.hpp"
  19 #include "xbt/graph.h"
  20
  21 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(instr_routing, instr, "Tracing platform hierarchy");
  22
  23 static std::vector<simgrid::instr::NetZoneContainer*> currentContainer; /* push and pop, used only in creation */
  24
  25 static const char* instr_node_name(xbt_node_t node)
  26 {
  27   return static_cast<char*>(xbt_graph_node_get_data(node));
  28 }
  29
  30 static container_t lowestCommonAncestor(container_t a1, container_t a2)
  31 {
  32   // this is only an optimization (since most of a1 and a2 share the same parent)
  33   if (a1->father_ == a2->father_)
  34     return a1->father_;
  35
  36   // create an array with all ancestors of a1
  37   std::vector<container_t> ancestors_a1;
  38   container_t p = a1->father_;
  39   while (p) {
  40     ancestors_a1.push_back(p);
  41     p = p->father_;
  42   }
  43
  44   // create an array with all ancestors of a2
  45   std::vector<container_t> ancestors_a2;
  46   p = a2->father_;
  47   while (p) {
  48     ancestors_a2.push_back(p);
  49     p = p->father_;
  50   }
  51
  52   // find the lowest ancestor
  53   p     = nullptr;
  54   int i = ancestors_a1.size() - 1;
  55   int j = ancestors_a2.size() - 1;
  56   while (i >= 0 && j >= 0) {
  57     container_t a1p = ancestors_a1.at(i);
  58     container_t a2p = ancestors_a2.at(j);
  59     if (a1p == a2p) {
  60       p = a1p;
  61     } else {
  62       break;
  63     }
  64     i--;
  65     j--;
  66   }
  67   return p;
  68 }
  69
  70 static void linkContainers(container_t src, container_t dst, std::set<std::string>* filter)
  71 {
  72   // ignore loopback
  73   if (src->get_name() == "__loopback__" || dst->get_name() == "__loopback__") {
  74     XBT_DEBUG("  linkContainers: ignoring loopback link");
  75     return;
  76   }
  77
  78   // find common father
  79   container_t father = lowestCommonAncestor(src, dst);
  80   if (not father) {
  81     xbt_die("common father unknown, this is a tracing problem");
  82   }
  83
  84   // check if we already register this pair (we only need one direction)
  85   std::string aux1 = src->get_name() + dst->get_name();
  86   std::string aux2 = dst->get_name() + src->get_name();
  87   if (filter->find(aux1) != filter->end()) {
  88     XBT_DEBUG("  linkContainers: already registered %s <-> %s (1)", src->get_cname(), dst->get_cname());
  89     return;
  90   }
  91   if (filter->find(aux2) != filter->end()) {
  92     XBT_DEBUG("  linkContainers: already registered %s <-> %s (2)", dst->get_cname(), src->get_cname());
  93     return;
  94   }
  95
  96   // ok, not found, register it
  97   filter->insert(aux1);
  98   filter->insert(aux2);
  99
 100   // declare type
 101   std::string link_typename = father->type_->get_name() + "-" + src->type_->get_name() +
 102                               std::to_string(src->type_->get_id()) + "-" + dst->type_->get_name() +
 103                               std::to_string(dst->type_->get_id());
 104   simgrid::instr::LinkType* link = father->type_->by_name_or_create(link_typename, src->type_, dst->type_);
 105   link->set_calling_container(father);
 106
 107   // register EDGE types for triva configuration
 108   trivaEdgeTypes.insert(link->get_name());
 109
 110   // create the link
 111   static long long counter = 0;
 112
 113   std::string key = std::to_string(counter);
 114   counter++;
 115
 116   link->start_event(src, "topology", key);
 117   link->end_event(dst, "topology", key);
 118
 119   XBT_DEBUG("  linkContainers %s <-> %s", src->get_cname(), dst->get_cname());
 120 }
 121
 122 static void recursiveGraphExtraction(simgrid::s4u::NetZone* netzone, container_t container,
 123                                      std::set<std::string>* filter)
 124 {
 125   if (not TRACE_platform_topology()) {
 126     XBT_DEBUG("Graph extraction disabled by user.");
 127     return;
 128   }
 129   XBT_DEBUG("Graph extraction for NetZone = %s", netzone->get_cname());
 130   if (not netzone->get_children()->empty()) {
 131     // bottom-up recursion
 132     for (auto const& nz_son : *netzone->get_children()) {
 133       container_t child_container = container->children_.at(nz_son->get_cname());
 134       recursiveGraphExtraction(nz_son, child_container, filter);
 135     }
 136   }
 137
 138   xbt_graph_t graph                        = xbt_graph_new_graph(0, nullptr);
 139   std::map<std::string, xbt_node_t>* nodes = new std::map<std::string, xbt_node_t>;
 140   std::map<std::string, xbt_edge_t>* edges = new std::map<std::string, xbt_edge_t>;
 141
 142   static_cast<simgrid::kernel::routing::NetZoneImpl*>(netzone)->get_graph(graph, nodes, edges);
 143   for (auto elm : *edges) {
 144     xbt_edge_t edge = elm.second;
 145     linkContainers(simgrid::instr::Container::by_name(static_cast<const char*>(edge->src->data)),
 146                    simgrid::instr::Container::by_name(static_cast<const char*>(edge->dst->data)), filter);
 147   }
 148   delete nodes;
 149   delete edges;
 150   xbt_graph_free_graph(graph, xbt_free_f, xbt_free_f, nullptr);
 151 }
 152
 153 /*
 154  * Callbacks
 155  */
 156 static void instr_netzone_on_creation(simgrid::s4u::NetZone& netzone)
 157 {
 158   std::string id = netzone.get_name();
 159   if (simgrid::instr::Container::get_root() == nullptr) {
 160     simgrid::instr::NetZoneContainer* root = new simgrid::instr::NetZoneContainer(id, 0, nullptr);
 161
 162     if (TRACE_smpi_is_enabled()) {
 163       simgrid::instr::ContainerType* mpi = root->type_->by_name_or_create<simgrid::instr::ContainerType>("MPI");
 164       if (not TRACE_smpi_is_grouped())
 165         mpi->by_name_or_create<simgrid::instr::StateType>("MPI_STATE");
 166       root->type_->by_name_or_create("MPI_LINK", mpi, mpi);
 167       // TODO See if we can move this to the LoadBalancer plugin
 168       root->type_->by_name_or_create("MIGRATE_LINK", mpi, mpi);
 169       mpi->by_name_or_create<simgrid::instr::StateType>("MIGRATE_STATE");
 170     }
 171
 172     if (TRACE_needs_platform()) {
 173       currentContainer.push_back(root);
 174     }
 175     return;
 176   }
 177
 178   if (TRACE_needs_platform()) {
 179     simgrid::instr::NetZoneContainer* container =
 180         new simgrid::instr::NetZoneContainer(id, currentContainer.size(), currentContainer.back());
 181     currentContainer.push_back(container);
 182   }
 183 }
 184
 185 static void instr_link_on_creation(simgrid::s4u::Link& link)
 186 {
 187   if (currentContainer.empty()) // No ongoing parsing. Are you creating the loopback?
 188     return;
 189
 190   container_t container = new simgrid::instr::Container(link.get_name(), "LINK", currentContainer.back());
 191
 192   if ((TRACE_categorized() || TRACE_uncategorized() || TRACE_platform()) && (not TRACE_disable_link())) {
 193     simgrid::instr::VariableType* bandwidth = container->type_->by_name_or_create("bandwidth", "");
 194     bandwidth->set_calling_container(container);
 195     bandwidth->set_event(0, link.get_bandwidth());
 196     simgrid::instr::VariableType* latency = container->type_->by_name_or_create("latency", "");
 197     latency->set_calling_container(container);
 198     latency->set_event(0, link.get_latency());
 199   }
 200   if (TRACE_uncategorized()) {
 201     container->type_->by_name_or_create("bandwidth_used", "0.5 0.5 0.5");
 202   }
 203 }
 204
 205 static void instr_host_on_creation(simgrid::s4u::Host& host)
 206 {
 207   container_t container = new simgrid::instr::HostContainer(host, currentContainer.back());
 208   container_t root      = simgrid::instr::Container::get_root();
 209
 210   if ((TRACE_categorized() || TRACE_uncategorized() || TRACE_platform()) && (not TRACE_disable_speed())) {
 211     simgrid::instr::VariableType* power = container->type_->by_name_or_create("power", "");
 212     power->set_calling_container(container);
 213     power->set_event(0, host.getSpeed());
 214   }
 215
 216   if (TRACE_uncategorized())
 217     container->type_->by_name_or_create("power_used", "0.5 0.5 0.5");
 218
 219   if (TRACE_smpi_is_enabled() && TRACE_smpi_is_grouped()) {
 220     simgrid::instr::ContainerType* mpi = container->type_->by_name_or_create<simgrid::instr::ContainerType>("MPI");
 221     mpi->by_name_or_create<simgrid::instr::StateType>("MPI_STATE");
 222     // TODO See if we can move this to the LoadBalancer plugin
 223     root->type_->by_name_or_create("MIGRATE_LINK", mpi, mpi);
 224     mpi->by_name_or_create<simgrid::instr::StateType>("MIGRATE_STATE");
 225   }
 226 }
 227
 228 static void instr_host_on_speed_change(simgrid::s4u::Host& host)
 229 {
 230   simgrid::instr::Container::by_name(host.get_cname())
 231       ->get_variable("power")
 232       ->set_event(surf_get_clock(), host.get_core_count() * host.get_available_speed());
 233 }
 234
 235 static void instr_cpu_action_on_state_change(simgrid::surf::CpuAction* action)
 236 {
 237   simgrid::surf::Cpu* cpu = static_cast<simgrid::surf::Cpu*>(action->get_variable()->get_constraint(0)->get_id());
 238   TRACE_surf_resource_set_utilization("HOST", "power_used", cpu->get_cname(), action->get_category(),
 239                                       action->get_variable()->get_value(), action->get_last_update(),
 240                                       SIMIX_get_clock() - action->get_last_update());
 241 }
 242
 243 static void instr_link_on_communication_state_change(simgrid::kernel::resource::NetworkAction* action)
 244 {
 245   int n = action->get_variable()->get_number_of_constraint();
 246
 247   for (int i = 0; i < n; i++) {
 248     simgrid::kernel::lmm::Constraint* constraint = action->get_variable()->get_constraint(i);
 249     simgrid::kernel::resource::LinkImpl* link = static_cast<simgrid::kernel::resource::LinkImpl*>(constraint->get_id());
 250     double value = action->get_variable()->get_value() * action->get_variable()->get_constraint_weight(i);
 251     TRACE_surf_resource_set_utilization("LINK", "bandwidth_used", link->get_cname(), action->get_category(), value,
 252                                         action->get_last_update(), SIMIX_get_clock() - action->get_last_update());
 253   }
 254 }
 255 static void instr_link_on_bandwidth_change(simgrid::s4u::Link& link)
 256 {
 257   simgrid::instr::Container::by_name(link.get_cname())
 258       ->get_variable("bandwidth")
 259       ->set_event(surf_get_clock(), sg_bandwidth_factor * link.get_bandwidth());
 260 }
 261
 262 static void instr_netpoint_on_creation(simgrid::kernel::routing::NetPoint* netpoint)
 263 {
 264   if (netpoint->is_router())
 265     new simgrid::instr::RouterContainer(netpoint->get_cname(), currentContainer.back());
 266 }
 267
 268 static void instr_on_platform_created()
 269 {
 270   currentContainer.clear();
 271   std::set<std::string>* filter = new std::set<std::string>;
 272   XBT_DEBUG("Starting graph extraction.");
 273   recursiveGraphExtraction(simgrid::s4u::Engine::get_instance()->get_netzone_root(),
 274                            simgrid::instr::Container::get_root(), filter);
 275   XBT_DEBUG("Graph extraction finished.");
 276   delete filter;
 277   TRACE_paje_dump_buffer(true);
 278 }
 279
 280 static void instr_actor_on_creation(simgrid::s4u::ActorPtr actor)
 281 {
 282   container_t root      = simgrid::instr::Container::get_root();
 283   container_t container = simgrid::instr::Container::by_name(actor->get_host()->get_name());
 284
 285   container->create_child(instr_pid(actor.get()), "ACTOR");
 286   simgrid::instr::ContainerType* actor_type =
 287       container->type_->by_name_or_create<simgrid::instr::ContainerType>("ACTOR");
 288   simgrid::instr::StateType* state = actor_type->by_name_or_create<simgrid::instr::StateType>("ACTOR_STATE");
 289   state->add_entity_value("suspend", "1 0 1");
 290   state->add_entity_value("sleep", "1 1 0");
 291   state->add_entity_value("receive", "1 0 0");
 292   state->add_entity_value("send", "0 0 1");
 293   state->add_entity_value("task_execute", "0 1 1");
 294   root->type_->by_name_or_create("ACTOR_LINK", actor_type, actor_type);
 295   root->type_->by_name_or_create("ACTOR_TASK_LINK", actor_type, actor_type);
 296
 297   actor->on_exit(
 298       [](int status, void* actor) {
 299         if (status == SMX_EXIT_FAILURE)
 300           // kill means that this actor no longer exists, let's destroy it
 301           simgrid::instr::Container::by_name(instr_pid(static_cast<simgrid::s4u::Actor*>(actor)))->remove_from_parent();
 302       },
 303       actor->get_impl());
 304 }
 305
 306 static long long int counter = 0;
 307
 308 static void instr_actor_on_migration_start(simgrid::s4u::ActorPtr actor)
 309 {
 310   // start link
 311   container_t container = simgrid::instr::Container::by_name(instr_pid(actor.get()));
 312   simgrid::instr::Container::get_root()->get_link("ACTOR_LINK")->start_event(container, "M", std::to_string(counter));
 313
 314   // destroy existing container of this process
 315   container->remove_from_parent();
 316 }
 317
 318 static void instr_actor_on_migration_end(simgrid::s4u::ActorPtr actor)
 319 {
 320   // create new container on the new_host location
 321   simgrid::instr::Container::by_name(actor->get_host()->get_name())->create_child(instr_pid(actor.get()), "ACTOR");
 322   // end link
 323   simgrid::instr::Container::get_root()
 324       ->get_link("ACTOR_LINK")
 325       ->end_event(simgrid::instr::Container::by_name(instr_pid(actor.get())), "M", std::to_string(counter));
 326   counter++;
 327 }
 328
 329 static void instr_vm_on_creation(simgrid::s4u::Host& host)
 330 {
 331   container_t container             = new simgrid::instr::HostContainer(host, currentContainer.back());
 332   container_t root                  = simgrid::instr::Container::get_root();
 333   simgrid::instr::ContainerType* vm = container->type_->by_name_or_create<simgrid::instr::ContainerType>("VM");
 334   simgrid::instr::StateType* state  = vm->by_name_or_create<simgrid::instr::StateType>("VM_STATE");
 335   state->add_entity_value("suspend", "1 0 1");
 336   state->add_entity_value("sleep", "1 1 0");
 337   state->add_entity_value("receive", "1 0 0");
 338   state->add_entity_value("send", "0 0 1");
 339   state->add_entity_value("task_execute", "0 1 1");
 340   root->type_->by_name_or_create("VM_LINK", vm, vm);
 341   root->type_->by_name_or_create("VM_ACTOR_LINK", vm, vm);
 342 }
 343
 344 void instr_define_callbacks()
 345 {
 346   // always need the callbacks to zones (we need only the root zone), to create the rootContainer and the rootType
 347   // properly
 348   if (TRACE_needs_platform()) {
 349     simgrid::s4u::on_platform_created.connect(instr_on_platform_created);
 350     simgrid::s4u::Host::on_creation.connect(instr_host_on_creation);
 351     simgrid::s4u::Host::on_speed_change.connect(instr_host_on_speed_change);
 352     simgrid::s4u::Link::on_creation.connect(instr_link_on_creation);
 353     simgrid::s4u::Link::on_bandwidth_change.connect(instr_link_on_bandwidth_change);
 354     simgrid::s4u::NetZone::on_seal.connect([](simgrid::s4u::NetZone& /*netzone*/) { currentContainer.pop_back(); });
 355     simgrid::kernel::routing::NetPoint::onCreation.connect(instr_netpoint_on_creation);
 356   }
 357   simgrid::s4u::NetZone::on_creation.connect(instr_netzone_on_creation);
 358
 359   simgrid::surf::CpuAction::on_state_change.connect(instr_cpu_action_on_state_change);
 360   simgrid::s4u::Link::on_communication_state_change.connect(instr_link_on_communication_state_change);
 361
 362   if (TRACE_actor_is_enabled()) {
 363     simgrid::s4u::Actor::on_creation.connect(instr_actor_on_creation);
 364     simgrid::s4u::Actor::on_suspend.connect([](simgrid::s4u::ActorPtr actor) {
 365       simgrid::instr::Container::by_name(instr_pid(actor.get()))->get_state("ACTOR_STATE")->push_event("suspend");
 366     });
 367     simgrid::s4u::Actor::on_resume.connect([](simgrid::s4u::ActorPtr actor) {
 368       simgrid::instr::Container::by_name(instr_pid(actor.get()))->get_state("ACTOR_STATE")->pop_event();
 369     });
 370     simgrid::s4u::Actor::on_sleep.connect([](simgrid::s4u::ActorPtr actor) {
 371       simgrid::instr::Container::by_name(instr_pid(actor.get()))->get_state("ACTOR_STATE")->push_event("sleep");
 372     });
 373     simgrid::s4u::Actor::on_wake_up.connect([](simgrid::s4u::ActorPtr actor) {
 374       simgrid::instr::Container::by_name(instr_pid(actor.get()))->get_state("ACTOR_STATE")->pop_event();
 375     });
 376     simgrid::s4u::Actor::on_migration_start.connect(instr_actor_on_migration_start);
 377     simgrid::s4u::Actor::on_migration_end.connect(instr_actor_on_migration_end);
 378   }
 379
 380   if (TRACE_vm_is_enabled()) {
 381     simgrid::s4u::Host::on_creation.connect(instr_vm_on_creation);
 382     simgrid::s4u::VirtualMachine::on_start.connect([](simgrid::s4u::VirtualMachine& vm) {
 383       simgrid::instr::Container::by_name(vm.get_name())->get_state("VM_STATE")->push_event("start");
 384     });
 385     simgrid::s4u::VirtualMachine::on_started.connect([](simgrid::s4u::VirtualMachine& vm) {
 386       simgrid::instr::Container::by_name(vm.get_name())->get_state("VM_STATE")->pop_event();
 387     });
 388     simgrid::s4u::VirtualMachine::on_suspend.connect([](simgrid::s4u::VirtualMachine& vm) {
 389       simgrid::instr::Container::by_name(vm.get_name())->get_state("VM_STATE")->push_event("suspend");
 390     });
 391     simgrid::s4u::VirtualMachine::on_resume.connect([](simgrid::s4u::VirtualMachine& vm) {
 392       simgrid::instr::Container::by_name(vm.get_name())->get_state("VM_STATE")->pop_event();
 393     });
 394     simgrid::s4u::Host::on_destruction.connect(
 395         [](simgrid::s4u::Host& host) { simgrid::instr::Container::by_name(host.get_name())->remove_from_parent(); });
 396   }
 397 }
 398 /*
 399  * user categories support
 400  */
 401 static void recursiveNewVariableType(std::string new_typename, std::string color, simgrid::instr::Type* root)
 402 {
 403   if (root->get_name() == "HOST" || root->get_name() == "VM")
 404     root->by_name_or_create(std::string("p") + new_typename, color);
 405
 406   if (root->get_name() == "LINK")
 407     root->by_name_or_create(std::string("b") + new_typename, color);
 408
 409   for (auto elm : root->children_) {
 410     recursiveNewVariableType(new_typename, color, elm.second);
 411   }
 412 }
 413
 414 void instr_new_variable_type(std::string new_typename, std::string color)
 415 {
 416   recursiveNewVariableType(new_typename, color, simgrid::instr::Container::get_root()->type_);
 417 }
 418
 419 static void recursiveNewUserVariableType(std::string father_type, std::string new_typename, std::string color,
 420                                          simgrid::instr::Type* root)
 421 {
 422   if (root->get_name() == father_type) {
 423     root->by_name_or_create(new_typename, color);
 424   }
 425   for (auto elm : root->children_)
 426     recursiveNewUserVariableType(father_type, new_typename, color, elm.second);
 427 }
 428
 429 void instr_new_user_variable_type(std::string father_type, std::string new_typename, std::string color)
 430 {
 431   recursiveNewUserVariableType(father_type, new_typename, color, simgrid::instr::Container::get_root()->type_);
 432 }
 433
 434 static void recursiveNewUserStateType(std::string father_type, std::string new_typename, simgrid::instr::Type* root)
 435 {
 436   if (root->get_name() == father_type)
 437     root->by_name_or_create<simgrid::instr::StateType>(new_typename);
 438
 439   for (auto elm : root->children_)
 440     recursiveNewUserStateType(father_type, new_typename, elm.second);
 441 }
 442
 443 void instr_new_user_state_type(std::string father_type, std::string new_typename)
 444 {
 445   recursiveNewUserStateType(father_type, new_typename, simgrid::instr::Container::get_root()->type_);
 446 }
 447
 448 static void recursiveNewValueForUserStateType(std::string type_name, const char* val, std::string color,
 449                                               simgrid::instr::Type* root)
 450 {
 451   if (root->get_name() == type_name)
 452     static_cast<simgrid::instr::StateType*>(root)->add_entity_value(val, color);
 453
 454   for (auto elm : root->children_)
 455     recursiveNewValueForUserStateType(type_name, val, color, elm.second);
 456 }
 457
 458 void instr_new_value_for_user_state_type(std::string type_name, const char* value, std::string color)
 459 {
 460   recursiveNewValueForUserStateType(type_name, value, color, simgrid::instr::Container::get_root()->type_);
 461 }
 462
 463 #define GRAPHICATOR_SUPPORT_FUNCTIONS
 464
 465 static void recursiveXBTGraphExtraction(xbt_graph_t graph, std::map<std::string, xbt_node_t>* nodes,
 466                                         std::map<std::string, xbt_edge_t>* edges, sg_netzone_t netzone,
 467                                         container_t container)
 468 {
 469   if (not netzone->get_children()->empty()) {
 470     // bottom-up recursion
 471     for (auto const& netzone_child : *netzone->get_children()) {
 472       container_t child_container = container->children_.at(netzone_child->get_cname());
 473       recursiveXBTGraphExtraction(graph, nodes, edges, netzone_child, child_container);
 474     }
 475   }
 476
 477   static_cast<simgrid::kernel::routing::NetZoneImpl*>(netzone)->get_graph(graph, nodes, edges);
 478 }
 479
 480 xbt_graph_t instr_routing_platform_graph()
 481 {
 482   xbt_graph_t ret                          = xbt_graph_new_graph(0, nullptr);
 483   std::map<std::string, xbt_node_t>* nodes = new std::map<std::string, xbt_node_t>;
 484   std::map<std::string, xbt_edge_t>* edges = new std::map<std::string, xbt_edge_t>;
 485   recursiveXBTGraphExtraction(ret, nodes, edges, simgrid::s4u::Engine::get_instance()->get_netzone_root(),
 486                               simgrid::instr::Container::get_root());
 487   delete nodes;
 488   delete edges;
 489   return ret;
 490 }
 491
 492 void instr_routing_platform_graph_export_graphviz(xbt_graph_t g, const char* filename)
 493 {
 494   unsigned int cursor = 0;
 495   xbt_node_t node     = nullptr;
 496   xbt_edge_t edge     = nullptr;
 497
 498   FILE* file = fopen(filename, "w");
 499   xbt_assert(file, "Failed to open %s \n", filename);
 500
 501   if (g->directed)
 502     fprintf(file, "digraph test {\n");
 503   else
 504     fprintf(file, "graph test {\n");
 505
 506   fprintf(file, "  graph [overlap=scale]\n");
 507
 508   fprintf(file, "  node [shape=box, style=filled]\n");
 509   fprintf(file, "  node [width=.3, height=.3, style=filled, color=skyblue]\n\n");
 510
 511   xbt_dynar_foreach (g->nodes, cursor, node) {
 512     fprintf(file, "  \"%s\";\n", instr_node_name(node));
 513   }
 514   xbt_dynar_foreach (g->edges, cursor, edge) {
 515     const char* src_s = instr_node_name(edge->src);
 516     const char* dst_s = instr_node_name(edge->dst);
 517     if (g->directed)
 518       fprintf(file, "  \"%s\" -> \"%s\";\n", src_s, dst_s);
 519     else
 520       fprintf(file, "  \"%s\" -- \"%s\";\n", src_s, dst_s);
 521   }
 522   fprintf(file, "}\n");
 523   fclose(file);
 524 }