1 /* Copyright (c) 2016. 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_BLOCKING_SIMCALL_HPP
8 #define SIMGRID_SIMIX_BLOCKING_SIMCALL_HPP
14 #include <xbt/sysdep.h>
18 #include <xbt/future.hpp>
19 #include <simgrid/kernel/future.hpp>
20 #include <simgrid/simix.h>
21 #include <simgrid/simix.hpp>
23 XBT_PUBLIC(void) simcall_run_blocking(std::function<void()> const& code);
28 XBT_PUBLIC(void) unblock(smx_process_t process);
30 /** Execute some code in kernel mode and wakes up the process when
31 * the result is available.
33 * It is given a callback which is executed in the kernel SimGrid and
34 * returns a simgrid::kernel::Future<T>. The kernel blocks the process
35 * until the Future is ready and either the value wrapped in the future
36 * to the process or raises the exception stored in the Future in the process.
38 * This can be used to implement blocking calls without adding new simcalls.
39 * One downside of this approach is that we don't have any semantic on what
40 * the process is waiting. This might be a problem for the model-checker and
41 * we'll have to devise a way to make it work.
43 * @param code Kernel code returning a `simgrid::kernel::Future<T>`
44 * @return Value of the kernel future
45 * @exception Exception from the kernel future
48 auto kernelSync(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_process_t self = SIMIX_process_self();
55 simgrid::xbt::Result<T> result;
57 simcall_run_blocking([&result, self, &code]{
60 future.then([&result, self](simgrid::kernel::Future<T> value) {
61 simgrid::xbt::setPromise(result, value);
62 simgrid::simix::unblock(self);
66 result.set_exception(std::current_exception());
67 simgrid::simix::unblock(self);
73 /** A blocking (`wait()`-based) future for SIMIX processes */
75 // TODO, .wait_until()
77 // TODO, simgrid::simix::when_all - wait for all future to be ready (this one is simple!)
78 // TODO, simgrid::simix::when_any - wait for any future to be ready
83 Future(simgrid::kernel::Future<T> future) : future_(std::move(future)) {}
85 bool valid() const { return future_.valid(); }
89 throw std::future_error(std::future_errc::no_state);
90 smx_process_t self = SIMIX_process_self();
91 simgrid::xbt::Result<T> result;
92 simcall_run_blocking([this, &result, self]{
94 // When the kernel future is ready...
95 this->future_.then([this, &result, self](simgrid::kernel::Future<T> value) {
96 // ... wake up the process with the result of the kernel future.
97 simgrid::xbt::setPromise(result, value);
98 simgrid::simix::unblock(self);
102 result.set_exception(std::current_exception());
103 simgrid::simix::unblock(self);
108 bool is_ready() const
111 throw std::future_error(std::future_errc::no_state);
112 return future_.is_ready();
116 // The future is ready! We don't have to wait:
117 if (this->is_ready())
119 // The future is not ready. We have to delegate to the SimGrid kernel:
120 std::exception_ptr exception;
121 smx_process_t self = SIMIX_process_self();
122 simcall_run_blocking([this, &exception, self]{
124 // When the kernel future is ready...
125 this->future_.then([this, self](simgrid::kernel::Future<T> value) {
126 // ...store it the simix kernel and wake up.
127 this->future_ = std::move(value);
128 simgrid::simix::unblock(self);
132 exception = std::current_exception();
133 simgrid::simix::unblock(self);
138 // We wrap an event-based kernel future:
139 simgrid::kernel::Future<T> future_;
142 /** Start some asynchronous work
144 * @param code SimGrid kernel code which returns a simgrid::kernel::Future
145 * @return User future
148 auto kernelAsync(F code)
149 -> Future<decltype(code().get())>
151 typedef decltype(code().get()) T;
153 // Execute the code in the kernel and get the kernel simcall:
154 simgrid::kernel::Future<T> future =
155 simgrid::simix::kernelImmediate(std::move(code));
157 // Wrap tyhe kernel simcall in a user simcall:
158 return simgrid::simix::Future<T>(std::move(future));