X-Git-Url: http://bilbo.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/7f4f03348bd07609e258eb3b545bdafc2c881847..40ee10e13b61bfb28374d96ade010a262b5abd44:/include/simgrid/simix.hpp diff --git a/include/simgrid/simix.hpp b/include/simgrid/simix.hpp index 1829bad3a3..338c3372ae 100644 --- a/include/simgrid/simix.hpp +++ b/include/simgrid/simix.hpp @@ -1,5 +1,4 @@ -/* Copyright (c) 2007-2010, 2012-2015. The SimGrid Team. - * All rights reserved. */ +/* Copyright (c) 2007-2023. 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. */ @@ -7,84 +6,112 @@ #ifndef SIMGRID_SIMIX_HPP #define SIMGRID_SIMIX_HPP -#include +#include +#include +#include #include -#include -#include -#include +#include -#include -#include +XBT_PUBLIC void simcall_run_answered(std::function const& code, + simgrid::kernel::actor::SimcallObserver* observer); +XBT_PUBLIC void simcall_run_blocking(std::function const& code, + simgrid::kernel::actor::SimcallObserver* observer); +XBT_PUBLIC void simcall_run_object_access(std::function const& code, + simgrid::kernel::actor::ObjectAccessSimcallItem* item); -namespace simgrid { -namespace simix { +namespace simgrid::kernel::actor { -class Context; -class ContextFactory; +/** 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, and setters may use the simcall_object_access() variant (see below). + * + * 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 typename std::result_of_t simcall_answered(F&& code, SimcallObserver* observer = nullptr) +{ + // 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(code)(); -class ContextFactory { -private: - std::string name_; -public: - - ContextFactory(std::string name) : name_(std::move(name)) {} - virtual ~ContextFactory(); - virtual Context* create_context(std::function 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 - T* new_context(Args&&... args) - { - T* context = new T(std::forward(args)...); - this->declare_context(context, sizeof(T)); - return context; - } -}; + // 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; + simgrid::xbt::Result result; + simcall_run_answered([&result, &code] { simgrid::xbt::fulfill_promise(result, std::forward(code)); }, observer); + return result.get(); +} -class Context { -private: - std::function code_; - void_pfn_smxprocess_t cleanup_func_ = nullptr; - smx_process_t process_ = nullptr; -public: - bool iwannadie; -public: - Context(std::function 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; - } +/** Use a setter on the `item` object. That's a simcall only if running in parallel or with MC activated. + * + * Simulation without MC and without parallelism (contexts/nthreads=1) will not pay the price of a simcall for an + * harmless setter. When running in parallel, you want your write access to be done in a mutual exclusion way, while the + * getters can still occur out of order. + * + * When running in MC, you want to make this access visible to the checker. Actually in this case, it's not visible from + * the checker (and thus still use a fast track) if the setter is called from the actor that created the object. + */ +template typename std::result_of_t simcall_object_access(ObjectAccessSimcallItem* item, F&& code) +{ + // If we are in the maestro, we take the fast path and execute the code directly + if (simgrid::s4u::Actor::is_maestro()) + return std::forward(code)(); - // Virtual methods - virtual ~Context(); - virtual void stop(); - virtual void suspend() = 0; -}; + // If called from another thread, do a real simcall. It will be short-cut on need + using R = typename std::result_of_t; + simgrid::xbt::Result result; + simcall_run_object_access([&result, &code] { simgrid::xbt::fulfill_promise(result, std::forward(code)); }, item); + return result.get(); } + +/** Execute some code (that does not return immediately) in kernel context + * + * This is very similar to simcall_answered() 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 void simcall_blocking(F&& code, SimcallObserver* observer = nullptr) +{ + 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 result; + simcall_run_blocking([&result, &code] { simgrid::xbt::fulfill_promise(result, std::forward(code)); }, observer); + result.get(); // rethrow stored exception if any } -#endif \ No newline at end of file +template +auto simcall_blocking(F&& code, Observer* observer) -> decltype(observer->get_result()) +{ + simcall_blocking(std::forward(code), static_cast(observer)); + return observer->get_result(); +} +} // namespace simgrid::kernel::actor +#endif