src/kernel/context/ContextBoost.cpp

   1 /* Copyright (c) 2015-2017. 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 <cstdint>
   7
   8 #include <functional>
   9 #include <utility>
  10 #include <vector>
  11
  12 #include <boost/context/all.hpp>
  13
  14 #include <xbt/log.h>
  15 #include <xbt/xbt_os_thread.h>
  16
  17 #include "src/simix/smx_private.h"
  18 #include "src/internal_config.h"
  19 #include "src/kernel/context/ContextBoost.hpp"
  20
  21 XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(simix_context);
  22
  23 namespace simgrid {
  24 namespace kernel {
  25 namespace context {
  26
  27 class BoostSerialContext : public BoostContext {
  28 public:
  29   BoostSerialContext(std::function<void()> code,
  30       void_pfn_smxprocess_t cleanup_func,
  31       smx_actor_t process)
  32     : BoostContext(std::move(code), cleanup_func, process) {}
  33   void stop() override;
  34   void suspend() override;
  35 };
  36
  37 #if HAVE_THREAD_CONTEXTS
  38 class BoostParallelContext : public BoostContext {
  39 public:
  40   BoostParallelContext(std::function<void()> code,
  41       void_pfn_smxprocess_t cleanup_func,
  42       smx_actor_t process)
  43     : BoostContext(std::move(code), cleanup_func, process) {}
  44   void stop() override;
  45   void suspend() override;
  46   void resume() override;
  47 };
  48 #endif
  49
  50 // BoostContextFactory
  51
  52 bool BoostContext::parallel_                             = false;
  53 simgrid::xbt::Parmap<smx_actor_t>* BoostContext::parmap_ = nullptr;
  54 uintptr_t BoostContext::threads_working_                 = 0;
  55 xbt_os_thread_key_t BoostContext::worker_id_key_;
  56 unsigned long BoostContext::process_index_   = 0;
  57 BoostContext* BoostContext::maestro_context_ = nullptr;
  58 std::vector<BoostContext*> BoostContext::workers_context_;
  59
  60 BoostContextFactory::BoostContextFactory()
  61   : ContextFactory("BoostContextFactory")
  62 {
  63   BoostContext::parallel_ = SIMIX_context_is_parallel();
  64   if (BoostContext::parallel_) {
  65 #if HAVE_THREAD_CONTEXTS
  66     int nthreads = SIMIX_context_get_nthreads();
  67     BoostContext::parmap_ = new simgrid::xbt::Parmap<smx_actor_t>(nthreads, SIMIX_context_get_parallel_mode());
  68     BoostContext::workers_context_.clear();
  69     BoostContext::workers_context_.resize(nthreads, nullptr);
  70     BoostContext::maestro_context_ = nullptr;
  71     xbt_os_thread_key_create(&BoostContext::worker_id_key_);
  72 #else
  73     xbt_die("No thread support for parallel context execution");
  74 #endif
  75   }
  76 }
  77
  78 BoostContextFactory::~BoostContextFactory()
  79 {
  80 #if HAVE_THREAD_CONTEXTS
  81   if (BoostContext::parmap_) {
  82     delete BoostContext::parmap_;
  83     BoostContext::parmap_ = nullptr;
  84   }
  85   BoostContext::workers_context_.clear();
  86 #endif
  87 }
  88
  89 smx_context_t BoostContextFactory::create_context(std::function<void()> code, void_pfn_smxprocess_t cleanup_func,
  90                                                   smx_actor_t process)
  91 {
  92   BoostContext* context = nullptr;
  93   if (BoostContext::parallel_)
  94 #if HAVE_THREAD_CONTEXTS
  95     context = this->new_context<BoostParallelContext>(std::move(code), cleanup_func, process);
  96 #else
  97     xbt_die("No support for parallel execution");
  98 #endif
  99   else
 100     context = this->new_context<BoostSerialContext>(std::move(code), cleanup_func, process);
 101   return context;
 102 }
 103
 104 void BoostContextFactory::run_all()
 105 {
 106 #if HAVE_THREAD_CONTEXTS
 107   if (BoostContext::parallel_) {
 108     BoostContext::threads_working_ = 0;
 109     BoostContext::parmap_->apply(
 110         [](smx_actor_t process) {
 111           BoostContext* context = static_cast<BoostContext*>(process->context);
 112           return context->resume();
 113         },
 114         simix_global->process_to_run);
 115   } else
 116 #endif
 117   {
 118     if (simix_global->process_to_run.empty())
 119       return;
 120     smx_actor_t first_process    = simix_global->process_to_run.front();
 121     BoostContext::process_index_ = 1;
 122     /* execute the first process */
 123     static_cast<BoostContext*>(first_process->context)->resume();
 124   }
 125 }
 126
 127
 128 // BoostContext
 129
 130 static void smx_ctx_boost_wrapper(std::intptr_t arg)
 131 {
 132   BoostContext* context = reinterpret_cast<BoostContext*>(arg);
 133   (*context)();
 134   context->stop();
 135 }
 136
 137 BoostContext::BoostContext(std::function<void()> code,
 138     void_pfn_smxprocess_t cleanup_func, smx_actor_t process)
 139   : Context(std::move(code), cleanup_func, process)
 140 {
 141
 142   /* if the user provided a function for the process then use it, otherwise it is the context for maestro */
 143   if (has_code()) {
 144     this->stack_ = SIMIX_context_stack_new();
 145 // We need to pass the bottom of the stack to make_fcontext, depending on the stack direction it may be the lower
 146 // or higher address:
 147 #if PTH_STACKGROWTH == -1
 148     void* stack = static_cast<char*>(this->stack_) + smx_context_usable_stack_size - 1;
 149 #else
 150     void* stack = this->stack_;
 151 #endif
 152     this->fc_ = boost::context::make_fcontext(
 153                       stack,
 154                       smx_context_usable_stack_size,
 155                       smx_ctx_boost_wrapper);
 156   } else {
 157 #if HAVE_BOOST_CONTEXTS == 1
 158     this->fc_ = new boost::context::fcontext_t();
 159 #endif
 160     if (BoostContext::maestro_context_ == nullptr)
 161       BoostContext::maestro_context_ = this;
 162   }
 163 }
 164
 165 BoostContext::~BoostContext()
 166 {
 167 #if HAVE_BOOST_CONTEXTS == 1
 168   if (not this->stack_)
 169     delete this->fc_;
 170 #endif
 171   if (this == maestro_context_)
 172     maestro_context_ = nullptr;
 173   SIMIX_context_stack_delete(this->stack_);
 174 }
 175
 176 // BoostSerialContext
 177
 178 void BoostContext::resume()
 179 {
 180   SIMIX_context_set_current(this);
 181 #if HAVE_BOOST_CONTEXTS == 1
 182   boost::context::jump_fcontext(maestro_context_->fc_, this->fc_, reinterpret_cast<intptr_t>(this));
 183 #else
 184   boost::context::jump_fcontext(&maestro_context_->fc_, this->fc_, reinterpret_cast<intptr_t>(this));
 185 #endif
 186 }
 187
 188 void BoostSerialContext::suspend()
 189 {
 190   /* determine the next context */
 191   BoostSerialContext* next_context = nullptr;
 192   unsigned long int i              = process_index_;
 193   process_index_++;
 194
 195   if (i < simix_global->process_to_run.size()) {
 196     /* execute the next process */
 197     XBT_DEBUG("Run next process");
 198     next_context = static_cast<BoostSerialContext*>(simix_global->process_to_run[i]->context);
 199   } else {
 200     /* all processes were run, return to maestro */
 201     XBT_DEBUG("No more process to run");
 202     next_context = static_cast<BoostSerialContext*>(maestro_context_);
 203   }
 204   SIMIX_context_set_current(static_cast<smx_context_t>(next_context));
 205 #if HAVE_BOOST_CONTEXTS == 1
 206   boost::context::jump_fcontext(this->fc_, next_context->fc_, reinterpret_cast<pintptr_t>(next_context));
 207 #else
 208   boost::context::jump_fcontext(&this->fc_, next_context->fc_, reinterpret_cast<intptr_t>(next_context));
 209 #endif
 210 }
 211
 212 void BoostSerialContext::stop()
 213 {
 214   BoostContext::stop();
 215   this->suspend();
 216 }
 217
 218 // BoostParallelContext
 219
 220 #if HAVE_THREAD_CONTEXTS
 221
 222 void BoostParallelContext::suspend()
 223 {
 224   boost::optional<smx_actor_t> next_work = parmap_->next();
 225   BoostParallelContext* next_context;
 226   if (next_work) {
 227     XBT_DEBUG("Run next process");
 228     next_context = static_cast<BoostParallelContext*>(next_work.get()->context);
 229   } else {
 230     XBT_DEBUG("No more processes to run");
 231     uintptr_t worker_id = reinterpret_cast<uintptr_t>(xbt_os_thread_get_specific(worker_id_key_));
 232     next_context = static_cast<BoostParallelContext*>(workers_context_[worker_id]);
 233   }
 234
 235   SIMIX_context_set_current(static_cast<smx_context_t>(next_context));
 236 #if HAVE_BOOST_CONTEXTS == 1
 237   boost::context::jump_fcontext(this->fc_, next_context->fc_, reinterpret_cast<intptr_t>(next_context));
 238 #else
 239   boost::context::jump_fcontext(&this->fc_, next_context->fc_, reinterpret_cast<intptr_t>(next_context));
 240 #endif
 241 }
 242
 243 void BoostParallelContext::stop()
 244 {
 245   BoostContext::stop();
 246   this->suspend();
 247 }
 248
 249 void BoostParallelContext::resume()
 250 {
 251   uintptr_t worker_id = __sync_fetch_and_add(&threads_working_, 1);
 252   xbt_os_thread_set_specific(worker_id_key_, reinterpret_cast<void*>(worker_id));
 253
 254   BoostParallelContext* worker_context = static_cast<BoostParallelContext*>(SIMIX_context_self());
 255   workers_context_[worker_id] = worker_context;
 256
 257   SIMIX_context_set_current(this);
 258 #if HAVE_BOOST_CONTEXTS == 1
 259   boost::context::jump_fcontext(worker_context->fc_, this->fc_, reinterpret_cast<intptr_t>(this));
 260 #else
 261   boost::context::jump_fcontext(&worker_context->fc_, this->fc_, reinterpret_cast<intptr_t>(this));
 262 #endif
 263 }
 264
 265 #endif
 266
 267 XBT_PRIVATE ContextFactory* boost_factory()
 268 {
 269   XBT_VERB("Using Boost contexts. Welcome to the 21th century.");
 270   return new BoostContextFactory();
 271 }
 272
 273 }}} // namespace