X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/7e42dd535dfc0d68de20fba4b9fc5e480b56c74b..15f9e0adbd11d2a0736440004a2f71ef9cfccab8:/src/kernel/context/ContextUnix.cpp diff --git a/src/kernel/context/ContextUnix.cpp b/src/kernel/context/ContextUnix.cpp index e2641444c2..15cf789a31 100644 --- a/src/kernel/context/ContextUnix.cpp +++ b/src/kernel/context/ContextUnix.cpp @@ -11,6 +11,7 @@ #include "simgrid/Exception.hpp" #include "src/mc/mc_ignore.hpp" #include "src/simix/ActorImpl.hpp" +#include "src/simix/smx_private.hpp" #include "ContextUnix.hpp" @@ -29,50 +30,23 @@ namespace kernel { namespace context { // UContextFactory - -UContextFactory::UContextFactory() : ContextFactory("UContextFactory"), parallel_(SIMIX_context_is_parallel()) -{ - UContext::set_maestro(nullptr); - if (parallel_) - ParallelUContext::initialize(); -} - -UContextFactory::~UContextFactory() -{ - if (parallel_) - ParallelUContext::finalize(); -} - Context* UContextFactory::create_context(std::function code, void_pfn_smxprocess_t cleanup, smx_actor_t process) { if (parallel_) - return new_context(std::move(code), cleanup, process); + return new_context(std::move(code), cleanup, process, this); else - return new_context(std::move(code), cleanup, process); + return new_context(std::move(code), cleanup, process, this); } -/* This function is called by maestro at the beginning of a scheduling round to get all working threads executing some - * stuff It is much easier to understand what happens if you see the working threads as bodies that swap their soul for - * the ones of the simulated processes that must run. - */ -void UContextFactory::run_all() -{ - if (parallel_) - ParallelUContext::run_all(); - else - SerialUContext::run_all(); -} // UContext -UContext* UContext::maestro_context_ = nullptr; - -UContext::UContext(std::function code, void_pfn_smxprocess_t cleanup_func, smx_actor_t process) - : Context(std::move(code), cleanup_func, process) +UContext::UContext(std::function code, void_pfn_smxprocess_t cleanup_func, smx_actor_t process, + SwappedContextFactory* factory) + : SwappedContext(std::move(code), cleanup_func, process, factory) { /* if the user provided a function for the process then use it, otherwise it is the context for maestro */ if (has_code()) { - this->stack_ = SIMIX_context_stack_new(); getcontext(&this->uc_); this->uc_.uc_link = nullptr; this->uc_.uc_stack.ss_sp = sg_makecontext_stack_addr(this->stack_); @@ -84,8 +58,8 @@ UContext::UContext(std::function code, void_pfn_smxprocess_t cleanup_fun #endif UContext::make_ctx(&this->uc_, UContext::smx_ctx_sysv_wrapper, this); } else { - if (process != nullptr && maestro_context_ == nullptr) - maestro_context_ = this; + if (process != nullptr && get_maestro() == nullptr) + set_maestro(this); } #if SIMGRID_HAVE_MC @@ -95,10 +69,7 @@ UContext::UContext(std::function code, void_pfn_smxprocess_t cleanup_fun #endif } -UContext::~UContext() -{ - SIMIX_context_stack_delete(this->stack_); -} +UContext::~UContext() = default; // The name of this function is currently hardcoded in the code (as string). // Do not change it without fixing those references as well. @@ -135,151 +106,68 @@ void UContext::make_ctx(ucontext_t* ucp, void (*func)(int, int), UContext* arg) makecontext(ucp, (void (*)())func, 2, ctx_addr[0], ctx_addr[1]); } -inline void UContext::swap(UContext* from, UContext* to) +void UContext::swap_into(SwappedContext* to_) { + UContext* to = static_cast(to_); ASAN_ONLY(void* fake_stack = nullptr); ASAN_ONLY(to->asan_ctx_ = from); ASAN_START_SWITCH(from->asan_stop_ ? nullptr : &fake_stack, to->asan_stack_, to->asan_stack_size_); - swapcontext(&from->uc_, &to->uc_); + swapcontext(&this->uc_, &to->uc_); ASAN_FINISH_SWITCH(fake_stack, &from->asan_ctx_->asan_stack_, &from->asan_ctx_->asan_stack_size_); } -void UContext::stop() -{ - Context::stop(); - throw StopRequest(); -} - -// SerialUContext - -unsigned long SerialUContext::process_index_; /* index of the next process to run in the list of runnable processes */ - -void SerialUContext::suspend() -{ - /* determine the next context */ - SerialUContext* next_context; - unsigned long int i = process_index_; - process_index_++; - - if (i < simix_global->process_to_run.size()) { - /* execute the next process */ - XBT_DEBUG("Run next process"); - next_context = static_cast(simix_global->process_to_run[i]->context_); - } else { - /* all processes were run, return to maestro */ - XBT_DEBUG("No more process to run"); - next_context = static_cast(UContext::get_maestro()); - } - Context::set_current(next_context); - UContext::swap(this, next_context); -} - -void SerialUContext::resume() -{ - Context::set_current(this); - UContext::swap(UContext::get_maestro(), this); -} - -void SerialUContext::run_all() -{ - if (simix_global->process_to_run.empty()) - return; - smx_actor_t first_process = simix_global->process_to_run.front(); - process_index_ = 1; - static_cast(first_process->context_)->resume(); -} - // ParallelUContext -simgrid::xbt::Parmap* ParallelUContext::parmap_; -std::atomic ParallelUContext::threads_working_; /* number of threads that have started their work */ -thread_local uintptr_t ParallelUContext::worker_id_; /* thread-specific storage for the thread id */ -std::vector ParallelUContext::workers_context_; /* space to save the worker's context - * in each thread */ - -void ParallelUContext::initialize() -{ - parmap_ = nullptr; - workers_context_.clear(); - workers_context_.resize(SIMIX_context_get_nthreads(), nullptr); -} - -void ParallelUContext::finalize() -{ - delete parmap_; - parmap_ = nullptr; - workers_context_.clear(); -} - -void ParallelUContext::run_all() +/** Run one particular simulated process on the current thread. + * + * Only applied to the N first elements of the parmap array, where N is the amount of worker threads in the parmap. + * See ParallelUContext::run_all for details. + */ +void ParallelUContext::resume() { - threads_working_ = 0; - // Parmap_apply ensures that every working thread get an index in the process_to_run array (through an atomic - // fetch_and_add), and runs the ParallelUContext::resume function on that index - - // We lazily create the parmap because the parmap creates context with simix_global->context_factory (which might not - // be initialized when bootstrapping): - if (parmap_ == nullptr) - parmap_ = new simgrid::xbt::Parmap(SIMIX_context_get_nthreads(), SIMIX_context_get_parallel_mode()); - parmap_->apply( - [](smx_actor_t process) { - ParallelUContext* context = static_cast(process->context_); - context->resume(); - }, - simix_global->process_to_run); + // Save the thread number (my body) in an os-thread-specific area + worker_id_ = threads_working_.fetch_add(1, std::memory_order_relaxed); + // Save my current soul (either maestro, or one of the minions) in a permanent area + SwappedContext* worker_context = static_cast(self()); + workers_context_[worker_id_] = worker_context; + // Switch my soul and the actor's one + Context::set_current(this); + worker_context->swap_into(this); + // No body runs that soul anymore at this point, but it is stored in a safe place. + // When the executed actor will do a blocking action, SIMIX_process_yield() will call suspend(), below. } /** Yield * - * This function is called when a simulated process wants to yield back to the maestro in a blocking simcall. This - * naturally occurs within SIMIX_context_suspend(self->context), called from SIMIX_process_yield() Actually, it does not - * really yield back to maestro, but into the next process that must be executed. If no one is to be executed, then it - * yields to the initial soul that was in this working thread (that was saved in resume_parallel). + * This function is called when a simulated process wants to yield back to the maestro in a blocking simcall, + * ie in SIMIX_process_yield(). + * + * Actually, it does not really yield back to maestro, but directly into the next executable actor. + * + * This makes the parmap::apply awkward (see ParallelUContext::run_all()) because it only apply regularly + * on the few first elements of the array, but it saves a lot of context switches back to maestro, + * and directly forth to the next executable actor. */ void ParallelUContext::suspend() { - /* determine the next context */ - // Get the next soul to embody now: + // Get some more work to directly swap into the next executable actor instead of yielding back to the parmap boost::optional next_work = parmap_->next(); - ParallelUContext* next_context; + SwappedContext* next_context; if (next_work) { - // There is a next soul to embody (ie, a next process to resume) + // There is a next soul to embody (ie, another executable actor) XBT_DEBUG("Run next process"); next_context = static_cast(next_work.get()->context_); } else { - // All processes were run, go to the barrier + // All actors were run, go back to the parmap context XBT_DEBUG("No more processes to run"); // worker_id_ is the identity of my body, stored in thread_local when starting the scheduling round - // Deduce the initial soul of that body next_context = workers_context_[worker_id_]; // When given that soul, the body will wait for the next scheduling round } + // Get the next soul to run, either from another actor or the initial minion's one Context::set_current(next_context); - // Get the next soul to run, either simulated or initial minion's one: - UContext::swap(this, next_context); -} - -/** Run one particular simulated process on the current thread. */ -void ParallelUContext::resume() -{ - // What is my containing body? Store its number in os-thread-specific area : - worker_id_ = threads_working_.fetch_add(1, std::memory_order_relaxed); - // Get my current soul: - ParallelUContext* worker_context = static_cast(self()); - // Write down that this soul is hosted in that body (for now) - workers_context_[worker_id_] = worker_context; - // Write in simix that I switched my soul - Context::set_current(this); - // Actually do that using the relevant library call: - UContext::swap(worker_context, this); - // No body runs that soul anymore at this point. Instead the current body took the soul of simulated process The - // simulated process wakes back after the call to "SIMIX_context_suspend(self->context);" within - // smx_process.c::SIMIX_process_yield() - - // From now on, the simulated processes will change their soul with the next soul to execute (in suspend_parallel, - // below). When nobody is to be executed in this scheduling round, the last simulated process will take back the - // initial soul of the current working thread + this->swap_into(next_context); } XBT_PRIVATE ContextFactory* sysv_factory()