-/* Copyright (c) 2007-2010, 2012-2015. The SimGrid Team.
+/* Copyright (c) 2007-2022. The SimGrid Team.
* All rights reserved. */
/* This program is free software; you can redistribute it and/or modify it
#ifndef SIMGRID_SIMIX_HPP
#define SIMGRID_SIMIX_HPP
-#include <cstddef>
+#include <simgrid/s4u/Actor.hpp>
+#include <simgrid/simix.h>
+#include <xbt/promise.hpp>
+#include <xbt/signal.hpp>
#include <string>
-#include <utility>
-#include <memory>
-#include <functional>
-#include <future>
-#include <type_traits>
-
-#include <xbt/function_types.h>
-#include <simgrid/simix.h>
+#include <unordered_map>
-XBT_PUBLIC(void) simcall_run_kernel(std::function<void()> const& code);
+XBT_PUBLIC void simcall_run_kernel(std::function<void()> const& code,
+ simgrid::kernel::actor::SimcallObserver* observer);
+XBT_PUBLIC void simcall_run_blocking(std::function<void()> const& code,
+ simgrid::kernel::actor::SimcallObserver* observer);
namespace simgrid {
-namespace simix {
-
-template<class R, class F>
-void fulfill_promise(std::promise<R>& promise, F&& code)
+namespace kernel {
+namespace actor {
+
+/** Execute some code in kernel context on behalf of the user code.
+ *
+ * Every modification of the environment must be protected this way: every setter, constructor and similar.
+ * Getters don't have to be protected this way.
+ *
+ * This allows deterministic parallel simulation without any locking, even if almost nobody uses parallel simulation in
+ * SimGrid. More interestingly it makes every modification of the simulated world observable by the model-checker,
+ * allowing the whole MC business.
+ *
+ * It is highly inspired from the syscalls in a regular operating system, allowing the user code to get some specific
+ * code executed in the kernel context. But here, there is almost no security involved. Parameters get checked for
+ * finiteness but that's all. The main goal remain to ensure reproducible ordering of uncomparable events (in
+ * [parallel] simulation) and observability of events (in model-checking).
+ *
+ * The code passed as argument is supposed to terminate at the exact same simulated timestamp.
+ * Do not use it if your code may block waiting for a subsequent event, e.g. if you lock a mutex,
+ * you may need to wait for that mutex to be unlocked by its current owner.
+ * Potentially blocking simcall must be issued using simcall_blocking(), right below in this file.
+ */
+template <class F> typename std::result_of_t<F()> simcall(F&& code, SimcallObserver* observer = nullptr)
{
- try {
- promise.set_value(code());
- }
- catch(...) {
- promise.set_exception(std::current_exception());
- }
+ // If we are in the maestro, we take the fast path and execute the
+ // code directly without simcall marshalling/unmarshalling/dispatch:
+ if (s4u::Actor::is_maestro())
+ return std::forward<F>(code)();
+
+ // If we are in the application, pass the code to the maestro which
+ // executes it for us and reports the result. We use a std::future which
+ // conveniently handles the success/failure value for us.
+ using R = typename std::result_of_t<F()>;
+ simgrid::xbt::Result<R> result;
+ simcall_run_kernel([&result, &code] { simgrid::xbt::fulfill_promise(result, std::forward<F>(code)); }, observer);
+ return result.get();
}
-// special version for R=void because the previous code does not compile
-// in this case:
-template<class F>
-void fulfill_promise(std::promise<void>& promise, F&& code)
+/** Execute some code (that does not return immediately) in kernel context
+ *
+ * This is very similar to simcall() right above, but the calling actor will not get rescheduled until
+ * actor->simcall_answer() is called explicitly.
+ *
+ * This is meant for blocking actions. For example, locking a mutex is a blocking simcall.
+ * First it's a simcall because that's obviously a modification of the world. Then, that's a blocking simcall because if
+ * the mutex happens not to be free, the actor is added to a queue of actors in the mutex. Every mutex->unlock() takes
+ * the first actor from the queue, mark it as current owner of the mutex and call actor->simcall_answer() to mark that
+ * this mutex is now unblocked and ready to run again. If the mutex is initially free, the calling actor is unblocked
+ * right away with actor->simcall_answer() once the mutex is marked as locked.
+ *
+ * If your code never calls actor->simcall_answer() itself, the actor will never return from its simcall.
+ *
+ * The return value is obtained from observer->get_result() if it exists. Otherwise void is returned.
+ */
+template <class F> void simcall_blocking(F&& code, SimcallObserver* observer = nullptr)
{
- try {
- code();
- promise.set_value();
- }
- catch(...) {
- promise.set_exception(std::current_exception());
- }
+ xbt_assert(not s4u::Actor::is_maestro(), "Cannot execute blocking call in kernel mode");
+
+ // Pass the code to the maestro which executes it for us and reports the result. We use a std::future which
+ // conveniently handles the success/failure value for us.
+ simgrid::xbt::Result<void> result;
+ simcall_run_blocking([&result, &code] { simgrid::xbt::fulfill_promise(result, std::forward<F>(code)); }, observer);
+ result.get(); // rethrow stored exception if any
}
-template<class F>
-typename std::result_of<F()>::type kernel(F&& code)
+template <class F, class Observer>
+auto simcall_blocking(F&& code, Observer* observer) -> decltype(observer->get_result())
{
- typedef typename std::result_of<F()>::type R;
- std::promise<R> promise;
- simcall_run_kernel([&]{
- xbt_assert(SIMIX_is_maestro(), "Not in maestro");
- fulfill_promise(promise, code);
- });
- return promise.get_future().get();
+ simcall_blocking(std::forward<F>(code), static_cast<SimcallObserver*>(observer));
+ return observer->get_result();
}
+} // namespace actor
+} // namespace kernel
-class Context;
-class ContextFactory;
-
-class ContextFactory {
-private:
- std::string name_;
-public:
-
- ContextFactory(std::string name) : name_(std::move(name)) {}
- virtual ~ContextFactory();
- virtual Context* create_context(std::function<void()> code,
- void_pfn_smxprocess_t cleanup, smx_process_t process) = 0;
- virtual void run_all() = 0;
- virtual Context* self();
- std::string const& name() const
- {
- return name_;
- }
-private:
- void declare_context(void* T, std::size_t size);
-protected:
- template<class T, class... Args>
- T* new_context(Args&&... args)
- {
- T* context = new T(std::forward<Args>(args)...);
- this->declare_context(context, sizeof(T));
- return context;
- }
-};
-
-class Context {
-private:
- std::function<void()> code_;
- void_pfn_smxprocess_t cleanup_func_ = nullptr;
- smx_process_t process_ = nullptr;
-public:
- bool iwannadie;
-public:
- Context(std::function<void()> code,
- void_pfn_smxprocess_t cleanup_func,
- smx_process_t process);
- void operator()()
- {
- code_();
- }
- bool has_code() const
- {
- return (bool) code_;
- }
- smx_process_t process()
- {
- return this->process_;
- }
- void set_cleanup(void_pfn_smxprocess_t cleanup)
- {
- cleanup_func_ = cleanup;
- }
+namespace simix {
- // Virtual methods
- virtual ~Context();
- virtual void stop();
- virtual void suspend() = 0;
-};
+XBT_PUBLIC void unblock(smx_actor_t process);
-}
-}
+} // namespace simix
+} // namespace simgrid
-#endif
\ No newline at end of file
+#endif
