1 /* Copyright (c) 2007-2021. The SimGrid Team.
2 * All rights reserved. */
4 /* This program is free software; you can redistribute it and/or modify it
5 * under the terms of the license (GNU LGPL) which comes with this package. */
7 #ifndef SIMGRID_SIMIX_HPP
8 #define SIMGRID_SIMIX_HPP
10 #include <simgrid/simix.h>
11 #include <xbt/functional.hpp>
12 #include <xbt/promise.hpp>
13 #include <xbt/signal.hpp>
14 #include <xbt/utility.hpp>
16 #include <boost/heap/fibonacci_heap.hpp>
18 #include <unordered_map>
20 XBT_PUBLIC void simcall_run_kernel(std::function<void()> const& code,
21 simgrid::kernel::actor::SimcallObserver* observer);
22 XBT_PUBLIC void simcall_run_blocking(std::function<void()> const& code,
23 simgrid::kernel::actor::SimcallObserver* observer);
29 /** Execute some code in kernel context on behalf of the user code.
31 * Every modification of the environment must be protected this way: every setter, constructor and similar.
32 * Getters don't have to be protected this way.
34 * This allows deterministic parallel simulation without any locking, even if almost nobody uses parallel simulation in
35 * SimGrid. More interestingly it makes every modification of the simulated world observable by the model-checker,
36 * allowing the whole MC business.
38 * It is highly inspired from the syscalls in a regular operating system, allowing the user code to get some specific
39 * code executed in the kernel context. But here, there is almost no security involved. Parameters get checked for
40 * finiteness but that's all. The main goal remain to ensure reproducible ordering of uncomparable events (in
41 * [parallel] simulation) and observability of events (in model-checking).
43 * The code passed as argument is supposed to terminate at the exact same simulated timestamp.
44 * Do not use it if your code may block waiting for a subsequent event, e.g. if you lock a mutex,
45 * you may need to wait for that mutex to be unlocked by its current owner.
46 * Potentially blocking simcall must be issued using simcall_blocking(), right below in this file.
48 template <class F> typename std::result_of_t<F()> simcall(F&& code, SimcallObserver* observer = nullptr)
50 // If we are in the maestro, we take the fast path and execute the
51 // code directly without simcall marshalling/unmarshalling/dispatch:
52 if (SIMIX_is_maestro())
53 return std::forward<F>(code)();
55 // If we are in the application, pass the code to the maestro which
56 // executes it for us and reports the result. We use a std::future which
57 // conveniently handles the success/failure value for us.
58 using R = typename std::result_of_t<F()>;
59 simgrid::xbt::Result<R> result;
60 simcall_run_kernel([&result, &code] { simgrid::xbt::fulfill_promise(result, std::forward<F>(code)); }, observer);
64 /** Execute some code (that does not return immediately) in kernel context
66 * This is very similar to simcall() right above, but the calling actor will not get rescheduled until
67 * actor->simcall_answer() is called explicitly.
69 * This is meant for blocking actions. For example, locking a mutex is a blocking simcall.
70 * First it's a simcall because that's obviously a modification of the world. Then, that's a blocking simcall because if
71 * the mutex happens not to be free, the actor is added to a queue of actors in the mutex. Every mutex->unlock() takes
72 * the first actor from the queue, mark it as current owner of the mutex and call actor->simcall_answer() to mark that
73 * this mutex is now unblocked and ready to run again. If the mutex is initially free, the calling actor is unblocked
74 * right away with actor->simcall_answer() once the mutex is marked as locked.
76 * If your code never calls actor->simcall_answer() itself, the actor will never return from its simcall.
78 * The return value is obtained from observer->get_result() if it exists. Otherwise void is returned.
80 template <class F> void simcall_blocking(F&& code, SimcallObserver* observer = nullptr)
82 xbt_assert(not SIMIX_is_maestro(), "Cannot execute blocking call in kernel mode");
84 // Pass the code to the maestro which executes it for us and reports the result. We use a std::future which
85 // conveniently handles the success/failure value for us.
86 simgrid::xbt::Result<void> result;
87 simcall_run_blocking([&result, &code] { simgrid::xbt::fulfill_promise(result, std::forward<F>(code)); }, observer);
88 result.get(); // rethrow stored exception if any
91 template <class F, class Observer>
92 auto simcall_blocking(F&& code, Observer* observer) -> decltype(observer->get_result())
94 simcall_blocking(std::forward<F>(code), static_cast<SimcallObserver*>(observer));
95 return observer->get_result();
99 } // namespace simgrid
103 XBT_PUBLIC void unblock(smx_actor_t process);
105 inline auto& simix_timers() // avoid static initialization order fiasco
107 using TimerQelt = std::pair<double, Timer*>;
108 static boost::heap::fibonacci_heap<TimerQelt, boost::heap::compare<xbt::HeapComparator<TimerQelt>>> value;
112 /** @brief Timer datatype */
116 std::remove_reference_t<decltype(simix_timers())>::handle_type handle_;
118 Timer(double date, simgrid::xbt::Task<void()>&& callback) : date(date), callback(std::move(callback)) {}
120 simgrid::xbt::Task<void()> callback;
123 template <class F> static inline Timer* set(double date, F callback)
125 return set(date, simgrid::xbt::Task<void()>(std::move(callback)));
128 static Timer* set(double date, simgrid::xbt::Task<void()>&& callback);
129 static double next() { return simix_timers().empty() ? -1.0 : simix_timers().top().first; }
132 // In MC mode, the application sends these pointers to the MC
133 xbt_dynar_t simix_global_get_actors_addr();
134 xbt_dynar_t simix_global_get_dead_actors_addr();
137 } // namespace simgrid