src/instr/instr_platform.cpp

   1 /* Copyright (c) 2010-2020. 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/Comm.hpp"
  12 #include "simgrid/s4u/Engine.hpp"
  13 #include "simgrid/s4u/Exec.hpp"
  14 #include "simgrid/s4u/Host.hpp"
  15 #include "simgrid/s4u/VirtualMachine.hpp"
  16 #include "src/surf/cpu_interface.hpp"
  17 #include "src/surf/network_interface.hpp"
  18 #include "src/surf/surf_interface.hpp"
  19 #include "src/surf/xml/platf_private.hpp"
  20 #include "surf/surf.hpp"
  21 #include "xbt/graph.h"
  22
  23 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(instr_routing, instr, "Tracing platform hierarchy");
  24
  25 std::string instr_pid(simgrid::s4u::Actor const& proc)
  26 {
  27   return std::string(proc.get_name()) + "-" + std::to_string(proc.get_pid());
  28 }
  29
  30 static const char* instr_node_name(const s_xbt_node_t* node)
  31 {
  32   return static_cast<char*>(xbt_graph_node_get_data(node));
  33 }
  34
  35 static container_t lowestCommonAncestor(const simgrid::instr::Container* a1, const simgrid::instr::Container* a2)
  36 {
  37   // this is only an optimization (since most of a1 and a2 share the same parent)
  38   if (a1->father_ == a2->father_)
  39     return a1->father_;
  40
  41   // create an array with all ancestors of a1
  42   std::vector<container_t> ancestors_a1;
  43   container_t p = a1->father_;
  44   while (p) {
  45     ancestors_a1.push_back(p);
  46     p = p->father_;
  47   }
  48
  49   // create an array with all ancestors of a2
  50   std::vector<container_t> ancestors_a2;
  51   p = a2->father_;
  52   while (p) {
  53     ancestors_a2.push_back(p);
  54     p = p->father_;
  55   }
  56
  57   // find the lowest ancestor
  58   p     = nullptr;
  59   int i = ancestors_a1.size() - 1;
  60   int j = ancestors_a2.size() - 1;
  61   while (i >= 0 && j >= 0) {
  62     container_t a1p = ancestors_a1.at(i);
  63     const simgrid::instr::Container* a2p = ancestors_a2.at(j);
  64     if (a1p == a2p) {
  65       p = a1p;
  66     } else {
  67       break;
  68     }
  69     i--;
  70     j--;
  71   }
  72   return p;
  73 }
  74
  75 static void linkContainers(container_t src, container_t dst, std::set<std::string>* filter)
  76 {
  77   // ignore loopback
  78   if (src->get_name() == "__loopback__" || dst->get_name() == "__loopback__") {
  79     XBT_DEBUG("  linkContainers: ignoring loopback link");
  80     return;
  81   }
  82
  83   // find common father
  84   container_t father = lowestCommonAncestor(src, dst);
  85   if (not father) {
  86     xbt_die("common father unknown, this is a tracing problem");
  87   }
  88
  89   // check if we already register this pair (we only need one direction)
  90   std::string aux1 = src->get_name() + dst->get_name();
  91   std::string aux2 = dst->get_name() + src->get_name();
  92   if (filter->find(aux1) != filter->end()) {
  93     XBT_DEBUG("  linkContainers: already registered %s <-> %s (1)", src->get_cname(), dst->get_cname());
  94     return;
  95   }
  96   if (filter->find(aux2) != filter->end()) {
  97     XBT_DEBUG("  linkContainers: already registered %s <-> %s (2)", dst->get_cname(), src->get_cname());
  98     return;
  99   }
 100
 101   // ok, not found, register it
 102   filter->insert(aux1);
 103   filter->insert(aux2);
 104
 105   // declare type
 106   std::string link_typename = father->type_->get_name() + "-" + src->type_->get_name() +
 107                               std::to_string(src->type_->get_id()) + "-" + dst->type_->get_name() +
 108                               std::to_string(dst->type_->get_id());
 109   simgrid::instr::LinkType* link = father->type_->by_name_or_create(link_typename, src->type_, dst->type_);
 110   link->set_calling_container(father);
 111
 112   // create the link
 113   static long long counter = 0;
 114
 115   std::string key = std::to_string(counter);
 116   counter++;
 117
 118   link->start_event(src, "topology", key);
 119   link->end_event(dst, "topology", key);
 120
 121   XBT_DEBUG("  linkContainers %s <-> %s", src->get_cname(), dst->get_cname());
 122 }
 123
 124 static void recursiveGraphExtraction(const simgrid::s4u::NetZone* netzone, container_t container,
 125                                      std::set<std::string>* filter)
 126 {
 127   if (not TRACE_platform_topology()) {
 128     XBT_DEBUG("Graph extraction disabled by user.");
 129     return;
 130   }
 131   XBT_DEBUG("Graph extraction for NetZone = %s", netzone->get_cname());
 132   if (not netzone->get_children().empty()) {
 133     // bottom-up recursion
 134     for (auto const& nz_son : netzone->get_children()) {
 135       container_t child_container = container->children_.at(nz_son->get_name());
 136       recursiveGraphExtraction(nz_son, child_container, filter);
 137     }
 138   }
 139
 140   xbt_graph_t graph                        = xbt_graph_new_graph(0, nullptr);
 141   std::map<std::string, xbt_node_t>* nodes = new std::map<std::string, xbt_node_t>();
 142   std::map<std::string, xbt_edge_t>* edges = new std::map<std::string, xbt_edge_t>();
 143
 144   netzone->get_impl()->get_graph(graph, nodes, edges);
 145   for (auto elm : *edges) {
 146     const xbt_edge* edge = elm.second;
 147     linkContainers(simgrid::instr::Container::by_name(static_cast<const char*>(edge->src->data)),
 148                    simgrid::instr::Container::by_name(static_cast<const char*>(edge->dst->data)), filter);
 149   }
 150   delete nodes;
 151   delete edges;
 152   xbt_graph_free_graph(graph, xbt_free_f, xbt_free_f, nullptr);
 153 }
 154
 155 /*
 156  * Callbacks
 157  */
 158
 159 namespace simgrid {
 160 namespace instr {
 161
 162 static std::vector<NetZoneContainer*> currentContainer; /* push and pop, used only in creation */
 163 static void on_netzone_creation(s4u::NetZone const& netzone)
 164 {
 165   std::string id = netzone.get_name();
 166   if (Container::get_root() == nullptr) {
 167     NetZoneContainer* root = new NetZoneContainer(id, 0, nullptr);
 168     xbt_assert(Container::get_root() == root);
 169
 170     if (TRACE_smpi_is_enabled()) {
 171       ContainerType* mpi = root->type_->by_name_or_create<ContainerType>("MPI");
 172       if (not TRACE_smpi_is_grouped())
 173         mpi->by_name_or_create<StateType>("MPI_STATE");
 174       root->type_->by_name_or_create("MPI_LINK", mpi, mpi);
 175       // TODO See if we can move this to the LoadBalancer plugin
 176       root->type_->by_name_or_create("MIGRATE_LINK", mpi, mpi);
 177       mpi->by_name_or_create<StateType>("MIGRATE_STATE");
 178     }
 179
 180     if (TRACE_needs_platform()) {
 181       currentContainer.push_back(root);
 182     }
 183     return;
 184   }
 185
 186   if (TRACE_needs_platform()) {
 187     NetZoneContainer* container = new NetZoneContainer(id, currentContainer.size(), currentContainer.back());
 188     currentContainer.push_back(container);
 189   }
 190 }
 191
 192 static void on_link_creation(s4u::Link const& link)
 193 {
 194   if (currentContainer.empty()) // No ongoing parsing. Are you creating the loopback?
 195     return;
 196
 197   Container* container = new Container(link.get_name(), "LINK", currentContainer.back());
 198
 199   if ((TRACE_categorized() || TRACE_uncategorized() || TRACE_platform()) && (not TRACE_disable_link())) {
 200     VariableType* bandwidth = container->type_->by_name_or_create("bandwidth", "");
 201     bandwidth->set_calling_container(container);
 202     bandwidth->set_event(0, link.get_bandwidth());
 203     VariableType* latency = container->type_->by_name_or_create("latency", "");
 204     latency->set_calling_container(container);
 205     latency->set_event(0, link.get_latency());
 206   }
 207   if (TRACE_uncategorized()) {
 208     container->type_->by_name_or_create("bandwidth_used", "0.5 0.5 0.5");
 209   }
 210 }
 211
 212 static void on_host_creation(s4u::Host const& host)
 213 {
 214   Container* container  = new HostContainer(host, currentContainer.back());
 215   const Container* root = Container::get_root();
 216
 217   if ((TRACE_categorized() || TRACE_uncategorized() || TRACE_platform()) && (not TRACE_disable_speed())) {
 218     VariableType* speed = container->type_->by_name_or_create("speed", "");
 219     speed->set_calling_container(container);
 220     speed->set_event(0, host.get_speed());
 221
 222     VariableType* cores = container->type_->by_name_or_create("core_count", "");
 223     cores->set_calling_container(container);
 224     cores->set_event(0, host.get_core_count());
 225   }
 226
 227   if (TRACE_uncategorized())
 228     container->type_->by_name_or_create("speed_used", "0.5 0.5 0.5");
 229
 230   if (TRACE_smpi_is_enabled() && TRACE_smpi_is_grouped()) {
 231     ContainerType* mpi = container->type_->by_name_or_create<ContainerType>("MPI");
 232     mpi->by_name_or_create<StateType>("MPI_STATE");
 233     // TODO See if we can move this to the LoadBalancer plugin
 234     root->type_->by_name_or_create("MIGRATE_LINK", mpi, mpi);
 235     mpi->by_name_or_create<StateType>("MIGRATE_STATE");
 236   }
 237 }
 238
 239 static void on_host_speed_change(s4u::Host const& host)
 240 {
 241   Container::by_name(host.get_name())
 242       ->get_variable("speed")
 243       ->set_event(surf_get_clock(), host.get_core_count() * host.get_available_speed());
 244 }
 245
 246 static void on_action_state_change(kernel::resource::Action const& action,
 247                                    kernel::resource::Action::State /* previous */)
 248 {
 249   int n = action.get_variable()->get_number_of_constraint();
 250
 251   for (int i = 0; i < n; i++) {
 252     double value = action.get_variable()->get_value() * action.get_variable()->get_constraint_weight(i);
 253     /* Beware of composite actions: ptasks put links and cpus together. Extra pb: we cannot dynamic_cast from void* */
 254     kernel::resource::Resource* resource = action.get_variable()->get_constraint(i)->get_id();
 255     const kernel::resource::Cpu* cpu     = dynamic_cast<kernel::resource::Cpu*>(resource);
 256
 257     if (cpu != nullptr)
 258       resource_set_utilization("HOST", "speed_used", cpu->get_cname(), action.get_category(), value,
 259                                action.get_last_update(), SIMIX_get_clock() - action.get_last_update());
 260
 261     const kernel::resource::LinkImpl* link = dynamic_cast<kernel::resource::LinkImpl*>(resource);
 262
 263     if (link != nullptr)
 264       resource_set_utilization("LINK", "bandwidth_used", link->get_cname(), action.get_category(), value,
 265                                action.get_last_update(), SIMIX_get_clock() - action.get_last_update());
 266   }
 267 }
 268
 269 static void on_link_bandwidth_change(s4u::Link const& link)
 270 {
 271   Container::by_name(link.get_name())
 272       ->get_variable("bandwidth")
 273       ->set_event(surf_get_clock(), sg_bandwidth_factor * link.get_bandwidth());
 274 }
 275
 276 static void on_netpoint_creation(kernel::routing::NetPoint const& netpoint)
 277 {
 278   if (netpoint.is_router())
 279     new RouterContainer(netpoint.get_name(), currentContainer.back());
 280 }
 281
 282 static void on_platform_created()
 283 {
 284   currentContainer.clear();
 285   std::set<std::string>* filter = new std::set<std::string>();
 286   XBT_DEBUG("Starting graph extraction.");
 287   recursiveGraphExtraction(s4u::Engine::get_instance()->get_netzone_root(), Container::get_root(), filter);
 288   XBT_DEBUG("Graph extraction finished.");
 289   delete filter;
 290   TRACE_paje_dump_buffer(true);
 291 }
 292
 293 static void on_actor_creation(s4u::Actor const& actor)
 294 {
 295   const Container* root = Container::get_root();
 296   Container* container  = Container::by_name(actor.get_host()->get_name());
 297
 298   container->create_child(instr_pid(actor), "ACTOR");
 299   ContainerType* actor_type = container->type_->by_name_or_create<ContainerType>("ACTOR");
 300   StateType* state          = actor_type->by_name_or_create<StateType>("ACTOR_STATE");
 301   state->add_entity_value("suspend", "1 0 1");
 302   state->add_entity_value("sleep", "1 1 0");
 303   state->add_entity_value("receive", "1 0 0");
 304   state->add_entity_value("send", "0 0 1");
 305   state->add_entity_value("execute", "0 1 1");
 306   root->type_->by_name_or_create("ACTOR_LINK", actor_type, actor_type);
 307   root->type_->by_name_or_create("ACTOR_TASK_LINK", actor_type, actor_type);
 308
 309   std::string container_name = instr_pid(actor);
 310   actor.on_exit([container_name](bool failed) {
 311     if (failed)
 312       // kill means that this actor no longer exists, let's destroy it
 313       Container::by_name(container_name)->remove_from_parent();
 314   });
 315 }
 316
 317 static void on_actor_host_change(s4u::Actor const& actor, s4u::Host const& /*previous_location*/)
 318 {
 319   static long long int counter = 0;
 320   container_t container        = Container::by_name(instr_pid(actor));
 321   LinkType* link               = Container::get_root()->get_link("ACTOR_LINK");
 322
 323   // start link
 324   link->start_event(container, "M", std::to_string(counter));
 325   // destroy existing container of this process
 326   container->remove_from_parent();
 327   // create new container on the new_host location
 328   Container::by_name(actor.get_host()->get_name())->create_child(instr_pid(actor), "ACTOR");
 329   // end link
 330   link->end_event(Container::by_name(instr_pid(actor)), "M", std::to_string(counter));
 331   counter++;
 332 }
 333
 334 static void on_vm_creation(s4u::Host const& host)
 335 {
 336   const Container* container = new HostContainer(host, currentContainer.back());
 337   const Container* root      = Container::get_root();
 338   ContainerType* vm          = container->type_->by_name_or_create<ContainerType>("VM");
 339   StateType* state           = vm->by_name_or_create<StateType>("VM_STATE");
 340   state->add_entity_value("suspend", "1 0 1");
 341   state->add_entity_value("sleep", "1 1 0");
 342   state->add_entity_value("receive", "1 0 0");
 343   state->add_entity_value("send", "0 0 1");
 344   state->add_entity_value("execute", "0 1 1");
 345   root->type_->by_name_or_create("VM_LINK", vm, vm);
 346   root->type_->by_name_or_create("VM_ACTOR_LINK", vm, vm);
 347 }
 348
 349 void define_callbacks()
 350 {
 351   // always need the callbacks to zones (we need only the root zone), to create the rootContainer and the rootType
 352   // properly
 353   if (TRACE_needs_platform()) {
 354     s4u::Engine::on_platform_created.connect(on_platform_created);
 355     s4u::Host::on_creation.connect(on_host_creation);
 356     s4u::Host::on_speed_change.connect(on_host_speed_change);
 357     s4u::Link::on_creation.connect(on_link_creation);
 358     s4u::Link::on_bandwidth_change.connect(on_link_bandwidth_change);
 359     s4u::NetZone::on_seal.connect([](s4u::NetZone const& /*netzone*/) { currentContainer.pop_back(); });
 360     kernel::routing::NetPoint::on_creation.connect(on_netpoint_creation);
 361   }
 362   s4u::NetZone::on_creation.connect(on_netzone_creation);
 363
 364   kernel::resource::CpuAction::on_state_change.connect(on_action_state_change);
 365   s4u::Link::on_communication_state_change.connect(on_action_state_change);
 366
 367   if (TRACE_actor_is_enabled()) {
 368     s4u::Actor::on_creation.connect(on_actor_creation);
 369     s4u::Actor::on_destruction.connect([](s4u::Actor const& actor) {
 370       auto container = Container::by_name_or_null(instr_pid(actor));
 371       if (container != nullptr)
 372         container->remove_from_parent();
 373     });
 374     s4u::Actor::on_suspend.connect([](s4u::Actor const& actor) {
 375       Container::by_name(instr_pid(actor))->get_state("ACTOR_STATE")->push_event("suspend");
 376     });
 377     s4u::Actor::on_resume.connect(
 378         [](s4u::Actor const& actor) { Container::by_name(instr_pid(actor))->get_state("ACTOR_STATE")->pop_event(); });
 379     s4u::Actor::on_sleep.connect([](s4u::Actor const& actor) {
 380       Container::by_name(instr_pid(actor))->get_state("ACTOR_STATE")->push_event("sleep");
 381     });
 382     s4u::Actor::on_wake_up.connect(
 383         [](s4u::Actor const& actor) { Container::by_name(instr_pid(actor))->get_state("ACTOR_STATE")->pop_event(); });
 384     s4u::Exec::on_start.connect([](simgrid::s4u::Actor const& actor, s4u::Exec const&) {
 385       Container::by_name(instr_pid(actor))->get_state("ACTOR_STATE")->push_event("execute");
 386     });
 387     s4u::Exec::on_completion.connect([](s4u::Actor const& actor, s4u::Exec const&) {
 388       Container::by_name(instr_pid(actor))->get_state("ACTOR_STATE")->pop_event();
 389     });
 390     s4u::Comm::on_sender_start.connect([](s4u::Actor const& actor) {
 391       Container::by_name(instr_pid(actor))->get_state("ACTOR_STATE")->push_event("send");
 392     });
 393     s4u::Comm::on_receiver_start.connect([](s4u::Actor const& actor) {
 394       Container::by_name(instr_pid(actor))->get_state("ACTOR_STATE")->push_event("receive");
 395     });
 396     s4u::Comm::on_completion.connect(
 397         [](s4u::Actor const& actor) { Container::by_name(instr_pid(actor))->get_state("ACTOR_STATE")->pop_event(); });
 398     s4u::Actor::on_host_change.connect(on_actor_host_change);
 399   }
 400
 401   if (TRACE_vm_is_enabled()) {
 402     s4u::Host::on_creation.connect(on_vm_creation);
 403     s4u::VirtualMachine::on_start.connect([](s4u::VirtualMachine const& vm) {
 404       Container::by_name(vm.get_name())->get_state("VM_STATE")->push_event("start");
 405     });
 406     s4u::VirtualMachine::on_started.connect(
 407         [](s4u::VirtualMachine const& vm) { Container::by_name(vm.get_name())->get_state("VM_STATE")->pop_event(); });
 408     s4u::VirtualMachine::on_suspend.connect([](s4u::VirtualMachine const& vm) {
 409       Container::by_name(vm.get_name())->get_state("VM_STATE")->push_event("suspend");
 410     });
 411     s4u::VirtualMachine::on_resume.connect(
 412         [](s4u::VirtualMachine const& vm) { Container::by_name(vm.get_name())->get_state("VM_STATE")->pop_event(); });
 413     s4u::Host::on_destruction.connect(
 414         [](s4u::Host const& host) { Container::by_name(host.get_name())->remove_from_parent(); });
 415   }
 416 }
 417 } // namespace instr
 418 } // namespace simgrid
 419
 420 /*
 421  * user categories support
 422  */
 423 static void recursiveNewVariableType(const std::string& new_typename, const std::string& color,
 424                                      simgrid::instr::Type* root)
 425 {
 426   if (root->get_name() == "HOST" || root->get_name() == "VM")
 427     root->by_name_or_create(std::string("p") + new_typename, color);
 428
 429   if (root->get_name() == "LINK")
 430     root->by_name_or_create(std::string("b") + new_typename, color);
 431
 432   for (auto const& elm : root->children_) {
 433     recursiveNewVariableType(new_typename, color, elm.second.get());
 434   }
 435 }
 436
 437 void instr_new_variable_type(const std::string& new_typename, const std::string& color)
 438 {
 439   recursiveNewVariableType(new_typename, color, simgrid::instr::Container::get_root()->type_);
 440 }
 441
 442 static void recursiveNewUserVariableType(const std::string& father_type, const std::string& new_typename,
 443                                          const std::string& color, simgrid::instr::Type* root)
 444 {
 445   if (root->get_name() == father_type) {
 446     root->by_name_or_create(new_typename, color);
 447   }
 448   for (auto const& elm : root->children_)
 449     recursiveNewUserVariableType(father_type, new_typename, color, elm.second.get());
 450 }
 451
 452 void instr_new_user_variable_type(const std::string& father_type, const std::string& new_typename,
 453                                   const std::string& color)
 454 {
 455   recursiveNewUserVariableType(father_type, new_typename, color, simgrid::instr::Container::get_root()->type_);
 456 }
 457
 458 static void recursiveNewUserStateType(const std::string& father_type, const std::string& new_typename,
 459                                       simgrid::instr::Type* root)
 460 {
 461   if (root->get_name() == father_type)
 462     root->by_name_or_create<simgrid::instr::StateType>(new_typename);
 463
 464   for (auto const& elm : root->children_)
 465     recursiveNewUserStateType(father_type, new_typename, elm.second.get());
 466 }
 467
 468 void instr_new_user_state_type(const std::string& father_type, const std::string& new_typename)
 469 {
 470   recursiveNewUserStateType(father_type, new_typename, simgrid::instr::Container::get_root()->type_);
 471 }
 472
 473 static void recursiveNewValueForUserStateType(const std::string& type_name, const char* val, const std::string& color,
 474                                               simgrid::instr::Type* root)
 475 {
 476   if (root->get_name() == type_name)
 477     static_cast<simgrid::instr::StateType*>(root)->add_entity_value(val, color);
 478
 479   for (auto const& elm : root->children_)
 480     recursiveNewValueForUserStateType(type_name, val, color, elm.second.get());
 481 }
 482
 483 void instr_new_value_for_user_state_type(const std::string& type_name, const char* value, const std::string& color)
 484 {
 485   recursiveNewValueForUserStateType(type_name, value, color, simgrid::instr::Container::get_root()->type_);
 486 }
 487
 488 #define GRAPHICATOR_SUPPORT_FUNCTIONS
 489
 490 static void recursiveXBTGraphExtraction(const s_xbt_graph_t* graph, std::map<std::string, xbt_node_t>* nodes,
 491                                         std::map<std::string, xbt_edge_t>* edges, const_sg_netzone_t netzone,
 492                                         container_t container)
 493 {
 494   if (not netzone->get_children().empty()) {
 495     // bottom-up recursion
 496     for (auto const& netzone_child : netzone->get_children()) {
 497       container_t child_container = container->children_.at(netzone_child->get_name());
 498       recursiveXBTGraphExtraction(graph, nodes, edges, netzone_child, child_container);
 499     }
 500   }
 501
 502   netzone->get_impl()->get_graph(graph, nodes, edges);
 503 }
 504
 505 xbt_graph_t instr_routing_platform_graph()
 506 {
 507   xbt_graph_t ret                          = xbt_graph_new_graph(0, nullptr);
 508   std::map<std::string, xbt_node_t>* nodes = new std::map<std::string, xbt_node_t>();
 509   std::map<std::string, xbt_edge_t>* edges = new std::map<std::string, xbt_edge_t>();
 510   recursiveXBTGraphExtraction(ret, nodes, edges, simgrid::s4u::Engine::get_instance()->get_netzone_root(),
 511                               simgrid::instr::Container::get_root());
 512   delete nodes;
 513   delete edges;
 514   return ret;
 515 }
 516
 517 void instr_routing_platform_graph_export_graphviz(const s_xbt_graph_t* g, const char* filename)
 518 {
 519   unsigned int cursor = 0;
 520   xbt_node_t node     = nullptr;
 521   xbt_edge_t edge     = nullptr;
 522
 523   FILE* file = fopen(filename, "w");
 524   xbt_assert(file, "Failed to open %s \n", filename);
 525
 526   if (g->directed)
 527     fprintf(file, "digraph test {\n");
 528   else
 529     fprintf(file, "graph test {\n");
 530
 531   fprintf(file, "  graph [overlap=scale]\n");
 532
 533   fprintf(file, "  node [shape=box, style=filled]\n");
 534   fprintf(file, "  node [width=.3, height=.3, style=filled, color=skyblue]\n\n");
 535
 536   xbt_dynar_foreach (g->nodes, cursor, node) {
 537     fprintf(file, "  \"%s\";\n", instr_node_name(node));
 538   }
 539   xbt_dynar_foreach (g->edges, cursor, edge) {
 540     const char* src_s = instr_node_name(edge->src);
 541     const char* dst_s = instr_node_name(edge->dst);
 542     if (g->directed)
 543       fprintf(file, "  \"%s\" -> \"%s\";\n", src_s, dst_s);
 544     else
 545       fprintf(file, "  \"%s\" -- \"%s\";\n", src_s, dst_s);
 546   }
 547   fprintf(file, "}\n");
 548   fclose(file);
 549 }