-/* Copyright (c) 2009-2015. The SimGrid Team.
- * All rights reserved. */
+/* Copyright (c) 2009-2018. The SimGrid Team. All rights reserved. */
/* This program is free software; you can redistribute it and/or modify it
* under the terms of the license (GNU LGPL) which comes with this package. */
-/* \file UContext.cpp Context switching with ucontexts from System V */
+/* \file UContext.cpp Context switching with ucontexts from System V */
-#include <stdarg.h>
+#include "ContextUnix.hpp"
+#include "context_private.hpp"
-#include <functional>
-#include <ucontext.h> /* context relative declarations */
-
-#include "xbt/parmap.h"
-#include "src/simix/smx_private.h"
-#include "src/internal_config.h"
#include "mc/mc.h"
-
-/** Many integers are needed to store a pointer
- *
- * This is a bit paranoid about sizeof(smx_ctx_sysv_t) not being a multiple
- * of sizeof(int), but it doesn't harm. */
-#define CTX_ADDR_LEN \
- (sizeof(void*) / sizeof(int) + \
- !!(sizeof(void*) % sizeof(int)))
-
-/** A better makecontext
- *
- * Makecontext expects integer arguments, we the context
- * variable is decomposed into a serie of integers and
- * each integer is passed as argument to makecontext. */
-static void simgrid_makecontext(ucontext_t* ucp, void (*func)(int first, ...), void* arg)
-{
- int ctx_addr[CTX_ADDR_LEN];
- memcpy(ctx_addr, &arg, sizeof(void*));
- switch (CTX_ADDR_LEN) {
- case 1:
- makecontext(ucp, (void (*)())func, 1, ctx_addr[0]);
- break;
- case 2:
- makecontext(ucp, (void (*)()) func, 2, ctx_addr[0], ctx_addr[1]);
- break;
- default:
- xbt_die("Ucontexts are not supported on this arch yet (addr len = %zu/%zu = %zu)", sizeof(void*), sizeof(int), CTX_ADDR_LEN);
- }
-}
+#include "src/mc/mc_ignore.hpp"
+#include "src/simix/ActorImpl.hpp"
XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(simix_context);
-namespace simgrid {
-namespace kernel {
-namespace context {
- class UContext;
- class SerialUContext;
- class ParallelUContext;
- class UContextFactory;
-}}}
-
-#if HAVE_THREAD_CONTEXTS
-static xbt_parmap_t sysv_parmap;
-static simgrid::kernel::context::ParallelUContext** sysv_workers_context; /* space to save the worker's context in each thread */
-static uintptr_t sysv_threads_working; /* number of threads that have started their work */
-static xbt_os_thread_key_t sysv_worker_id_key; /* thread-specific storage for the thread id */
-#endif
-static unsigned long sysv_process_index = 0; /* index of the next process to run in the
- * list of runnable processes */
-static simgrid::kernel::context::UContext* sysv_maestro_context;
-static bool sysv_parallel;
+/** Many integers are needed to store a pointer
+ *
+ * Support up to two ints. */
+constexpr int CTX_ADDR_LEN = 2;
-// The name of this function is currently hardcoded in the code (as string).
-// Do not change it without fixing those references as well.
-static void smx_ctx_sysv_wrapper(int first, ...);
+static_assert(sizeof(simgrid::kernel::context::UContext*) <= CTX_ADDR_LEN * sizeof(int),
+ "Ucontexts are not supported on this arch yet");
namespace simgrid {
namespace kernel {
namespace context {
-class UContext : public Context {
-protected:
- ucontext_t uc_; /* the ucontext that executes the code */
- char *stack_ = nullptr; /* the thread stack */
-public:
- friend UContextFactory;
- UContext(std::function<void()> code,
- void_pfn_smxprocess_t cleanup_func, smx_actor_t process);
- ~UContext() override;
-};
-
-class SerialUContext : public UContext {
-public:
- SerialUContext(std::function<void()> code,
- void_pfn_smxprocess_t cleanup_func, smx_actor_t process)
- : UContext(std::move(code), cleanup_func, process)
- {}
- void stop() override;
- void suspend() override;
- void resume();
-};
-
-class ParallelUContext : public UContext {
-public:
- ParallelUContext(std::function<void()> code,
- void_pfn_smxprocess_t cleanup_func, smx_actor_t process)
- : UContext(std::move(code), cleanup_func, process)
- {}
- void stop() override;
- void suspend() override;
- void resume();
-};
-
-class UContextFactory : public ContextFactory {
-public:
- friend UContext;
- friend SerialUContext;
- friend ParallelUContext;
-
- UContextFactory();
- ~UContextFactory() override;
- Context* create_context(std::function<void()> code,
- void_pfn_smxprocess_t cleanup, smx_actor_t process) override;
- void run_all() override;
-};
-
-XBT_PRIVATE ContextFactory* sysv_factory()
-{
- XBT_VERB("Activating SYSV context factory");
- return new UContextFactory();
-}
+// UContextFactory
-UContextFactory::UContextFactory() : ContextFactory("UContextFactory")
+UContextFactory::UContextFactory() : ContextFactory("UContextFactory"), parallel_(SIMIX_context_is_parallel())
{
- if (SIMIX_context_is_parallel()) {
- sysv_parallel = true;
-#if HAVE_THREAD_CONTEXTS /* To use parallel ucontexts a thread pool is needed */
- int nthreads = SIMIX_context_get_nthreads();
- sysv_parmap = nullptr;
- sysv_workers_context = xbt_new(ParallelUContext*, nthreads);
- sysv_maestro_context = nullptr;
- xbt_os_thread_key_create(&sysv_worker_id_key);
+ UContext::setMaestro(nullptr);
+ if (parallel_) {
+#if HAVE_THREAD_CONTEXTS
+ ParallelUContext::initialize();
#else
- THROWF(arg_error, 0, "No thread support for parallel context execution");
+ xbt_die("No thread support for parallel context execution");
#endif
- } else {
- sysv_parallel = false;
}
}
UContextFactory::~UContextFactory()
{
#if HAVE_THREAD_CONTEXTS
- if (sysv_parmap)
- xbt_parmap_destroy(sysv_parmap);
- xbt_free(sysv_workers_context);
+ if (parallel_)
+ ParallelUContext::finalize();
#endif
}
-/* 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()
+Context* UContextFactory::create_context(std::function<void()> code, void_pfn_smxprocess_t cleanup, smx_actor_t process)
{
- if (sysv_parallel) {
- #if HAVE_THREAD_CONTEXTS
- sysv_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 smx_ctx_sysv_resume_parallel 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 (sysv_parmap == nullptr)
- sysv_parmap = xbt_parmap_new(
- SIMIX_context_get_nthreads(), SIMIX_context_get_parallel_mode());
-
- xbt_parmap_apply(sysv_parmap,
- [](void* arg) {
- smx_actor_t process = (smx_actor_t) arg;
- ParallelUContext* context = static_cast<ParallelUContext*>(process->context);
- context->resume();
- },
- simix_global->process_to_run);
- #else
- xbt_die("You asked for a parallel execution, but you don't have any threads.");
- #endif
- } else {
- // Serial:
- if (xbt_dynar_is_empty(simix_global->process_to_run))
- return;
-
- smx_actor_t first_process =
- xbt_dynar_get_as(simix_global->process_to_run, 0, smx_actor_t);
- sysv_process_index = 1;
- SerialUContext* context =
- static_cast<SerialUContext*>(first_process->context);
- context->resume();
- }
+#if HAVE_THREAD_CONTEXTS
+ if (parallel_)
+ return new_context<ParallelUContext>(std::move(code), cleanup, process);
+ else
+#endif
+ return new_context<SerialUContext>(std::move(code), cleanup, process);
}
-Context* UContextFactory::create_context(std::function<void()> code,
- void_pfn_smxprocess_t cleanup, smx_actor_t process)
+/* 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 (sysv_parallel)
- return new_context<ParallelUContext>(std::move(code), cleanup, process);
+#if HAVE_THREAD_CONTEXTS
+ if (parallel_)
+ ParallelUContext::run_all();
else
- return new_context<SerialUContext>(std::move(code), cleanup, process);
+#endif
+ SerialUContext::run_all();
}
-UContext::UContext(std::function<void()> code,
- void_pfn_smxprocess_t cleanup_func, smx_actor_t process)
- : Context(std::move(code), cleanup_func, process)
+// UContext
+
+UContext* UContext::maestro_context_ = nullptr;
+
+UContext::UContext(std::function<void()> code, void_pfn_smxprocess_t cleanup_func, smx_actor_t process)
+ : Context(std::move(code), cleanup_func, process)
{
/* if the user provided a function for the process then use it, otherwise it is the context for maestro */
if (has_code()) {
- this->stack_ = (char*) SIMIX_context_stack_new();
+ 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_);
this->uc_.uc_stack.ss_size = sg_makecontext_stack_size(smx_context_usable_stack_size);
- simgrid_makecontext(&this->uc_, smx_ctx_sysv_wrapper, this);
+#if PTH_STACKGROWTH == -1
+ ASAN_ONLY(this->asan_stack_ = static_cast<char*>(this->stack_) + smx_context_usable_stack_size);
+#else
+ ASAN_ONLY(this->asan_stack_ = this->stack_);
+#endif
+ UContext::make_ctx(&this->uc_, UContext::smx_ctx_sysv_wrapper, this);
} else {
- if (process != nullptr && sysv_maestro_context == nullptr)
- sysv_maestro_context = this;
+ if (process != nullptr && maestro_context_ == nullptr)
+ maestro_context_ = this;
}
-#if HAVE_MC
+#if SIMGRID_HAVE_MC
if (MC_is_active() && has_code()) {
- MC_register_stack_area(this->stack_, process,
- &(this->uc_), smx_context_usable_stack_size);
+ MC_register_stack_area(this->stack_, process, &(this->uc_), smx_context_usable_stack_size);
}
#endif
}
SIMIX_context_stack_delete(this->stack_);
}
-}}} // namespace simgrid::kernel::context
-
-static void smx_ctx_sysv_wrapper(int first, ...)
+// The name of this function is currently hardcoded in the code (as string).
+// Do not change it without fixing those references as well.
+void UContext::smx_ctx_sysv_wrapper(int i1, int i2)
{
// Rebuild the Context* pointer from the integers:
- int ctx_addr[CTX_ADDR_LEN];
+ int ctx_addr[CTX_ADDR_LEN] = {i1, i2};
simgrid::kernel::context::UContext* context;
- ctx_addr[0] = first;
- if (CTX_ADDR_LEN > 1) {
- va_list ap;
- va_start(ap, first);
- for (unsigned i = 1; i < CTX_ADDR_LEN; i++)
- ctx_addr[i] = va_arg(ap, int);
- va_end(ap);
+ memcpy(&context, ctx_addr, sizeof context);
+
+ ASAN_FINISH_SWITCH(nullptr, &context->asan_ctx_->asan_stack_, &context->asan_ctx_->asan_stack_size_);
+ try {
+ (*context)();
+ context->Context::stop();
+ } catch (simgrid::kernel::context::Context::StopRequest const&) {
+ XBT_DEBUG("Caught a StopRequest");
}
- memcpy(&context, ctx_addr, sizeof(simgrid::kernel::context::UContext*));
+ ASAN_ONLY(context->asan_stop_ = true);
+ context->suspend();
+}
- (*context)();
- context->stop();
+/** A better makecontext
+ *
+ * Makecontext expects integer arguments, we the context variable is decomposed into a serie of integers and each
+ * integer is passed as argument to makecontext.
+ */
+void UContext::make_ctx(ucontext_t* ucp, void (*func)(int, int), UContext* arg)
+{
+ int ctx_addr[CTX_ADDR_LEN]{};
+ memcpy(ctx_addr, &arg, sizeof arg);
+ makecontext(ucp, (void (*)())func, 2, ctx_addr[0], ctx_addr[1]);
}
-namespace simgrid {
-namespace kernel {
-namespace context {
+inline void UContext::swap(UContext* from, UContext* 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_);
+ ASAN_FINISH_SWITCH(fake_stack, &from->asan_ctx_->asan_stack_, &from->asan_ctx_->asan_stack_size_);
+}
-void SerialUContext::stop()
+void UContext::stop()
{
Context::stop();
- this->suspend();
+ 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 = nullptr;
- unsigned long int i = sysv_process_index++;
+ SerialUContext* next_context;
+ unsigned long int i = process_index_;
+ process_index_++;
- if (i < xbt_dynar_length(simix_global->process_to_run)) {
+ if (i < simix_global->process_to_run.size()) {
/* execute the next process */
XBT_DEBUG("Run next process");
- next_context = (SerialUContext*) xbt_dynar_get_as(
- simix_global->process_to_run,i, smx_actor_t)->context;
- }
- else {
+ next_context = static_cast<SerialUContext*>(simix_global->process_to_run[i]->context);
+ } else {
/* all processes were run, return to maestro */
XBT_DEBUG("No more process to run");
- next_context = (SerialUContext*) sysv_maestro_context;
+ next_context = static_cast<SerialUContext*>(UContext::getMaestro());
}
SIMIX_context_set_current(next_context);
- swapcontext(&this->uc_, &next_context->uc_);
+ UContext::swap(this, next_context);
}
-// UContextSerial
-
void SerialUContext::resume()
{
SIMIX_context_set_current(this);
- swapcontext(&((SerialUContext*)sysv_maestro_context)->uc_, &this->uc_);
+ UContext::swap(UContext::getMaestro(), this);
}
-void ParallelUContext::stop()
+void SerialUContext::run_all()
{
- UContext::stop();
- this->suspend();
+ if (simix_global->process_to_run.empty())
+ return;
+ smx_actor_t first_process = simix_global->process_to_run.front();
+ process_index_ = 1;
+ static_cast<SerialUContext*>(first_process->context)->resume();
}
-/** Run one particular simulated process on the current thread. */
-void ParallelUContext::resume()
-{
+// ParallelUContext
+
#if HAVE_THREAD_CONTEXTS
- // What is my containing body?
- uintptr_t worker_id = __sync_fetch_and_add(&sysv_threads_working, 1);
- // Store the number of my containing body in os-thread-specific area :
- xbt_os_thread_set_specific(sysv_worker_id_key, (void*) worker_id);
- // Get my current soul:
- ParallelUContext* worker_context = (ParallelUContext*) SIMIX_context_self();
- // Write down that this soul is hosted in that body (for now)
- sysv_workers_context[worker_id] = worker_context;
- // Retrieve the system-level info that fuels this soul:
- ucontext_t* worker_stack = &((ParallelUContext*) worker_context)->uc_;
- // Write in simix that I switched my soul
- SIMIX_context_set_current(this);
- // Actually do that using the relevant library call:
- swapcontext(worker_stack, &this->uc_);
- // 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
-#endif
+simgrid::xbt::Parmap<smx_actor_t>* ParallelUContext::parmap_;
+std::atomic<uintptr_t> ParallelUContext::threads_working_; /* number of threads that have started their work */
+xbt_os_thread_key_t ParallelUContext::worker_id_key_; /* thread-specific storage for the thread id */
+std::vector<ParallelUContext*> 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);
+ xbt_os_thread_key_create(&worker_id_key_);
+}
+
+void ParallelUContext::finalize()
+{
+ delete parmap_;
+ parmap_ = nullptr;
+ workers_context_.clear();
+ xbt_os_thread_key_destroy(worker_id_key_);
+}
+
+void ParallelUContext::run_all()
+{
+ 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<smx_actor_t>(SIMIX_context_get_nthreads(), SIMIX_context_get_parallel_mode());
+ parmap_->apply(
+ [](smx_actor_t process) {
+ ParallelUContext* context = static_cast<ParallelUContext*>(process->context);
+ context->resume();
+ },
+ simix_global->process_to_run);
}
/** 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. 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).
*/
void ParallelUContext::suspend()
{
-#if HAVE_THREAD_CONTEXTS
/* determine the next context */
// Get the next soul to embody now:
- smx_actor_t next_work = (smx_actor_t) xbt_parmap_next(sysv_parmap);
- ParallelUContext* next_context = nullptr;
- // Will contain the next soul to run, either simulated or initial minion's one
- ucontext_t* next_stack;
-
- if (next_work != nullptr) {
+ boost::optional<smx_actor_t> next_work = parmap_->next();
+ ParallelUContext* next_context;
+ if (next_work) {
// There is a next soul to embody (ie, a next process to resume)
XBT_DEBUG("Run next process");
- next_context = (ParallelUContext*) next_work->context;
- }
- else {
+ next_context = static_cast<ParallelUContext*>(next_work.get()->context);
+ } else {
// All processes were run, go to the barrier
XBT_DEBUG("No more processes to run");
- // Get back the identity of my body that was stored when starting
- // the scheduling round
- uintptr_t worker_id =
- (uintptr_t) xbt_os_thread_get_specific(sysv_worker_id_key);
+ // Get back the identity of my body that was stored when starting the scheduling round
+ uintptr_t worker_id = reinterpret_cast<uintptr_t>(xbt_os_thread_get_specific(worker_id_key_));
// Deduce the initial soul of that body
- next_context = (ParallelUContext*) sysv_workers_context[worker_id];
+ next_context = workers_context_[worker_id];
// When given that soul, the body will wait for the next scheduling round
}
- next_stack = &next_context->uc_;
-
SIMIX_context_set_current(next_context);
- // Get that next soul:
- swapcontext(&this->uc_, next_stack);
-#endif
+ // Get the next soul to run, either simulated or initial minion's one:
+ UContext::swap(this, next_context);
}
-}}} // namespace simgrid::kernel::context
+/** Run one particular simulated process on the current thread. */
+void ParallelUContext::resume()
+{
+ // What is my containing body?
+ uintptr_t worker_id = threads_working_.fetch_add(1, std::memory_order_relaxed);
+ // Store the number of my containing body in os-thread-specific area :
+ xbt_os_thread_set_specific(worker_id_key_, reinterpret_cast<void*>(worker_id));
+ // Get my current soul:
+ ParallelUContext* worker_context = static_cast<ParallelUContext*>(SIMIX_context_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
+ SIMIX_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
+}
+
+#endif
+XBT_PRIVATE ContextFactory* sysv_factory()
+{
+ XBT_VERB("Activating SYSV context factory");
+ return new UContextFactory();
+}
+}}} // namespace simgrid::kernel::context
