1 /* Copyright (c) 2016-2019. The SimGrid Team. All rights reserved. */
3 /* This program is free software; you can redistribute it and/or modify it
4 * under the terms of the license (GNU LGPL) which comes with this package. */
6 #ifndef SIMGRID_SIMIX_BLOCKING_SIMCALL_HPP
7 #define SIMGRID_SIMIX_BLOCKING_SIMCALL_HPP
14 #include <xbt/sysdep.h>
16 #include <xbt/future.hpp>
17 #include <simgrid/kernel/future.hpp>
18 #include <simgrid/simix.h>
19 #include <simgrid/simix.hpp>
21 XBT_PUBLIC void simcall_run_blocking(std::function<void()> const& code);
26 XBT_PUBLIC void unblock(smx_actor_t process);
28 /** Execute some code in kernel mode and wakes up the actor when
29 * the result is available.
31 * It is given a callback which is executed in the SimGrid kernel and
32 * returns a `simgrid::kernel::Future<T>`. The kernel blocks the actor
33 * until the Future is ready and:
35 * - either returns the value wrapped in the future to the actor
37 * - or raises the exception stored in the future in the actor.
39 * This can be used to implement blocking calls without adding new simcalls.
40 * One downside of this approach is that we don't have any semantic on what
41 * the actor is waiting. This might be a problem for the model-checker and
42 * we'll have to devise a way to make it work.
44 * @param code Kernel code returning a `simgrid::kernel::Future<T>`
45 * @return Value of the kernel future
46 * @exception Exception from the kernel future
48 template <class F> auto kernel_sync(F code) -> decltype(code().get())
50 typedef decltype(code().get()) T;
51 if (SIMIX_is_maestro())
52 xbt_die("Can't execute blocking call in kernel mode");
54 smx_actor_t self = SIMIX_process_self();
55 simgrid::xbt::Result<T> result;
57 simcall_run_blocking([&result, self, &code]{
60 future.then_([&result, self](std::shared_ptr<simgrid::kernel::FutureState<T>>&& value) {
61 simgrid::xbt::set_promise(result, simgrid::kernel::Future<T>(value));
62 simgrid::simix::unblock(self);
66 result.set_exception(std::current_exception());
67 simgrid::simix::unblock(self);
73 XBT_ATTRIB_DEPRECATED_v323("Please use simix::kernel_sync()") auto kernelSync(F code) -> decltype(code().get())
75 return kernel_sync(code);
78 /** A blocking (`wait()`-based) future for SIMIX processes */
80 // TODO, .wait_until()
82 // TODO, simgrid::simix::when_all - wait for all future to be ready (this one is simple!)
83 // TODO, simgrid::simix::when_any - wait for any future to be ready
87 Future() { /* Nothing to do*/}
88 explicit Future(simgrid::kernel::Future<T> future) : future_(std::move(future)) {}
90 bool valid() const { return future_.valid(); }
94 throw std::future_error(std::future_errc::no_state);
95 smx_actor_t self = SIMIX_process_self();
96 simgrid::xbt::Result<T> result;
97 simcall_run_blocking([this, &result, self]{
99 // When the kernel future is ready...
100 this->future_.then_([&result, self](std::shared_ptr<simgrid::kernel::FutureState<T>>&& value) {
101 // ... wake up the process with the result of the kernel future.
102 simgrid::xbt::set_promise(result, simgrid::kernel::Future<T>(value));
103 simgrid::simix::unblock(self);
107 result.set_exception(std::current_exception());
108 simgrid::simix::unblock(self);
113 bool is_ready() const
116 throw std::future_error(std::future_errc::no_state);
117 return future_.is_ready();
121 // The future is ready! We don't have to wait:
122 if (this->is_ready())
124 // The future is not ready. We have to delegate to the SimGrid kernel:
125 std::exception_ptr exception;
126 smx_actor_t self = SIMIX_process_self();
127 simcall_run_blocking([this, &exception, self]{
129 // When the kernel future is ready...
130 this->future_.then_([this, self](std::shared_ptr<simgrid::kernel::FutureState<T>>&& value) {
131 // ...store it the simix kernel and wake up.
132 this->future_ = std::move(simgrid::kernel::Future<T>(value));
133 simgrid::simix::unblock(self);
137 exception = std::current_exception();
138 simgrid::simix::unblock(self);
143 // We wrap an event-based kernel future:
144 simgrid::kernel::Future<T> future_;
147 /** Start some asynchronous work
149 * @param code SimGrid kernel code which returns a simgrid::kernel::Future
150 * @return Actor future
152 template <class F> auto kernel_async(F code) -> Future<decltype(code().get())>
154 typedef decltype(code().get()) T;
156 // Execute the code in the kernel and get the kernel future:
157 simgrid::kernel::Future<T> future = simgrid::simix::simcall(std::move(code));
159 // Wrap the kernel future in a actor future:
160 return simgrid::simix::Future<T>(std::move(future));
163 XBT_ATTRIB_DEPRECATED_v323("Please use simix::kernel_sync()") auto kernelAsync(F code) -> Future<decltype(code().get())>
165 return kernel_async(code);