src/kernel/context/ContextBoost.cpp

   1 /* Copyright (c) 2015-2018. 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 "ContextBoost.hpp"
   7 #include "context_private.hpp"
   8 #include "src/simix/smx_private.hpp"
   9
  10 XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(simix_context);
  11
  12 namespace simgrid {
  13 namespace kernel {
  14 namespace context {
  15
  16 // BoostContextFactory
  17
  18 BoostContextFactory::BoostContextFactory()
  19     : ContextFactory("BoostContextFactory"), parallel_(SIMIX_context_is_parallel())
  20 {
  21   BoostContext::setMaestro(nullptr);
  22   if (parallel_) {
  23 #if HAVE_THREAD_CONTEXTS
  24     ParallelBoostContext::initialize();
  25 #else
  26     xbt_die("No thread support for parallel context execution");
  27 #endif
  28   }
  29 }
  30
  31 BoostContextFactory::~BoostContextFactory()
  32 {
  33 #if HAVE_THREAD_CONTEXTS
  34   if (parallel_)
  35     ParallelBoostContext::finalize();
  36 #endif
  37 }
  38
  39 smx_context_t BoostContextFactory::create_context(std::function<void()> code, void_pfn_smxprocess_t cleanup_func,
  40                                                   smx_actor_t process)
  41 {
  42 #if HAVE_THREAD_CONTEXTS
  43   if (parallel_)
  44     return this->new_context<ParallelBoostContext>(std::move(code), cleanup_func, process);
  45 #endif
  46
  47   return this->new_context<SerialBoostContext>(std::move(code), cleanup_func, process);
  48 }
  49
  50 void BoostContextFactory::run_all()
  51 {
  52 #if HAVE_THREAD_CONTEXTS
  53   if (parallel_)
  54     ParallelBoostContext::run_all();
  55   else
  56 #endif
  57     SerialBoostContext::run_all();
  58 }
  59
  60 // BoostContext
  61
  62 BoostContext* BoostContext::maestro_context_ = nullptr;
  63
  64 BoostContext::BoostContext(std::function<void()> code, void_pfn_smxprocess_t cleanup_func, smx_actor_t process)
  65     : Context(std::move(code), cleanup_func, process)
  66 {
  67
  68   /* if the user provided a function for the process then use it, otherwise it is the context for maestro */
  69   if (has_code()) {
  70     this->stack_ = SIMIX_context_stack_new();
  71     /* We need to pass the bottom of the stack to make_fcontext,
  72        depending on the stack direction it may be the lower or higher address: */
  73 #if PTH_STACKGROWTH == -1
  74     void* stack = static_cast<char*>(this->stack_) + smx_context_usable_stack_size;
  75 #else
  76     void* stack = this->stack_;
  77 #endif
  78     ASAN_ONLY(this->asan_stack_ = stack);
  79 #if BOOST_VERSION < 106100
  80     this->fc_ = boost::context::make_fcontext(stack, smx_context_usable_stack_size, BoostContext::wrapper);
  81 #else
  82     this->fc_ = boost::context::detail::make_fcontext(stack, smx_context_usable_stack_size, BoostContext::wrapper);
  83 #endif
  84   } else {
  85 #if BOOST_VERSION < 105600
  86     this->fc_ = new boost::context::fcontext_t();
  87 #endif
  88     if (BoostContext::maestro_context_ == nullptr)
  89       BoostContext::maestro_context_ = this;
  90   }
  91 }
  92
  93 BoostContext::~BoostContext()
  94 {
  95 #if BOOST_VERSION < 105600
  96   if (not this->stack_)
  97     delete this->fc_;
  98 #endif
  99   if (this == maestro_context_)
 100     maestro_context_ = nullptr;
 101   SIMIX_context_stack_delete(this->stack_);
 102 }
 103
 104 void BoostContext::wrapper(BoostContext::arg_type arg)
 105 {
 106 #if BOOST_VERSION < 106100
 107   BoostContext* context = reinterpret_cast<BoostContext*>(arg);
 108 #else
 109   BoostContext* context = static_cast<BoostContext**>(arg.data)[1];
 110   ASAN_ONLY(xbt_assert(context->asan_ctx_ == static_cast<BoostContext**>(arg.data)[0]));
 111   ASAN_FINISH_SWITCH(nullptr, &context->asan_ctx_->asan_stack_, &context->asan_ctx_->asan_stack_size_);
 112   static_cast<BoostContext**>(arg.data)[0]->fc_ = arg.fctx;
 113 #endif
 114   try {
 115     (*context)();
 116     context->Context::stop();
 117   } catch (StopRequest const&) {
 118     XBT_DEBUG("Caught a StopRequest");
 119   }
 120   ASAN_ONLY(context->asan_stop_ = true);
 121   context->suspend();
 122 }
 123
 124 inline void BoostContext::swap(BoostContext* from, BoostContext* to)
 125 {
 126 #if BOOST_VERSION < 105600
 127   boost::context::jump_fcontext(from->fc_, to->fc_, reinterpret_cast<intptr_t>(to));
 128 #elif BOOST_VERSION < 106100
 129   boost::context::jump_fcontext(&from->fc_, to->fc_, reinterpret_cast<intptr_t>(to));
 130 #else
 131   BoostContext* ctx[2] = {from, to};
 132   ASAN_ONLY(void* fake_stack = nullptr);
 133   ASAN_ONLY(to->asan_ctx_ = from);
 134   ASAN_START_SWITCH(from->asan_stop_ ? nullptr : &fake_stack, to->asan_stack_, to->asan_stack_size_);
 135   boost::context::detail::transfer_t arg = boost::context::detail::jump_fcontext(to->fc_, ctx);
 136   ASAN_ONLY(xbt_assert(from->asan_ctx_ == static_cast<BoostContext**>(arg.data)[0]));
 137   ASAN_FINISH_SWITCH(fake_stack, &from->asan_ctx_->asan_stack_, &from->asan_ctx_->asan_stack_size_);
 138   static_cast<BoostContext**>(arg.data)[0]->fc_ = arg.fctx;
 139 #endif
 140 }
 141
 142 void BoostContext::stop()
 143 {
 144   Context::stop();
 145   throw StopRequest();
 146 }
 147
 148 // SerialBoostContext
 149
 150 unsigned long SerialBoostContext::process_index_;
 151
 152 void SerialBoostContext::suspend()
 153 {
 154   /* determine the next context */
 155   SerialBoostContext* next_context;
 156   unsigned long int i = process_index_;
 157   process_index_++;
 158
 159   if (i < simix_global->process_to_run.size()) {
 160     /* execute the next process */
 161     XBT_DEBUG("Run next process");
 162     next_context = static_cast<SerialBoostContext*>(simix_global->process_to_run[i]->context_);
 163   } else {
 164     /* all processes were run, return to maestro */
 165     XBT_DEBUG("No more process to run");
 166     next_context = static_cast<SerialBoostContext*>(BoostContext::getMaestro());
 167   }
 168   SIMIX_context_set_current(next_context);
 169   BoostContext::swap(this, next_context);
 170 }
 171
 172 void SerialBoostContext::resume()
 173 {
 174   SIMIX_context_set_current(this);
 175   BoostContext::swap(BoostContext::getMaestro(), this);
 176 }
 177
 178 void SerialBoostContext::run_all()
 179 {
 180   if (simix_global->process_to_run.empty())
 181     return;
 182   smx_actor_t first_process = simix_global->process_to_run.front();
 183   process_index_            = 1;
 184   /* execute the first process */
 185   static_cast<SerialBoostContext*>(first_process->context_)->resume();
 186 }
 187
 188 // ParallelBoostContext
 189
 190 #if HAVE_THREAD_CONTEXTS
 191
 192 simgrid::xbt::Parmap<smx_actor_t>* ParallelBoostContext::parmap_;
 193 std::atomic<uintptr_t> ParallelBoostContext::threads_working_;
 194 thread_local uintptr_t ParallelBoostContext::worker_id_;
 195 std::vector<ParallelBoostContext*> ParallelBoostContext::workers_context_;
 196
 197 void ParallelBoostContext::initialize()
 198 {
 199   parmap_ = nullptr;
 200   workers_context_.clear();
 201   workers_context_.resize(SIMIX_context_get_nthreads(), nullptr);
 202 }
 203
 204 void ParallelBoostContext::finalize()
 205 {
 206   delete parmap_;
 207   parmap_ = nullptr;
 208   workers_context_.clear();
 209 }
 210
 211 void ParallelBoostContext::run_all()
 212 {
 213   threads_working_ = 0;
 214   if (parmap_ == nullptr)
 215     parmap_ = new simgrid::xbt::Parmap<smx_actor_t>(SIMIX_context_get_nthreads(), SIMIX_context_get_parallel_mode());
 216   parmap_->apply(
 217       [](smx_actor_t process) {
 218         ParallelBoostContext* context = static_cast<ParallelBoostContext*>(process->context_);
 219         context->resume();
 220       },
 221       simix_global->process_to_run);
 222 }
 223
 224 void ParallelBoostContext::suspend()
 225 {
 226   boost::optional<smx_actor_t> next_work = parmap_->next();
 227   ParallelBoostContext* next_context;
 228   if (next_work) {
 229     XBT_DEBUG("Run next process");
 230     next_context = static_cast<ParallelBoostContext*>(next_work.get()->context_);
 231   } else {
 232     XBT_DEBUG("No more processes to run");
 233     next_context = workers_context_[worker_id_];
 234   }
 235
 236   SIMIX_context_set_current(next_context);
 237   BoostContext::swap(this, next_context);
 238 }
 239
 240 void ParallelBoostContext::resume()
 241 {
 242   worker_id_ = threads_working_.fetch_add(1, std::memory_order_relaxed);
 243
 244   ParallelBoostContext* worker_context = static_cast<ParallelBoostContext*>(SIMIX_context_self());
 245   workers_context_[worker_id_]         = worker_context;
 246
 247   SIMIX_context_set_current(this);
 248   BoostContext::swap(worker_context, this);
 249 }
 250
 251 #endif
 252
 253 XBT_PRIVATE ContextFactory* boost_factory()
 254 {
 255   XBT_VERB("Using Boost contexts. Welcome to the 21th century.");
 256   return new BoostContextFactory();
 257 }
 258 }}} // namespace