mandatory to the model-checker. The simcalls, representing actors'
actions, are the transitions of the formal system. Verifying the
system requires to manipulate these transitions explicitly. This also
-allows to run safely the actors in parallel, even if this is less
+allows one to run the actors safely in parallel, even if this is less
commonly used by our users.
So, the key ideas here are:
Our futures are based on the C++ Concurrency Technical Specification
API, with a few differences:
- - The simulation kernel is single-threaded so we do not need
+ - The simulation kernel is single-threaded so we do not need
inter-thread synchronization for our futures.
- As the simulation kernel cannot block, `f.wait()` is not meaningful
template<class T>
T simgrid::kernel::FutureState<T>::get()
{
- if (status_ != FutureStatus::ready)
- xbt_die("Deadlock: this future is not ready");
+ xbt_assert(status_ == FutureStatus::ready, "Deadlock: this future is not ready");
status_ = FutureStatus::done;
if (exception_) {
std::exception_ptr exception = std::move(exception_);
simulation kernel and yield the control until the request is
fulfilled. The performance requirements are very high because
the actors usually do an inordinate amount of simcalls during the
-simulation.
+simulation.
As for real syscalls, the basic idea is to write the wanted call and
its arguments in a memory area that is specific to the actor, and
@code{cpp}
struct s_smx_simcall {
// Simcall number:
- e_smx_simcall_t call;
+ Simcall call;
// Issuing actor:
smx_actor_t issuer;
// Arguments of the simcall:
union u_smx_scalar result;
// Some additional stuff:
smx_timer_t timer;
- int mc_value;
};
@endcode
@code{cpp}
template<class F>
-typename std::result_of<F()>::type kernelImmediate(F&& code)
+typename std::result_of_t<F()> kernelImmediate(F&& code)
{
// If we are in the simulation kernel, we take the fast path and
// execute the code directly without simcall
// If we are in the application, pass the code to the simulation
// kernel which executes it for us and reports the result:
- typedef typename std::result_of<F()>::type R;
+ typedef typename std::result_of_t<F()> R;
simgrid::xbt::Result<R> result;
simcall_run_kernel([&]{
xbt_assert(SIMIX_is_maestro(), "Not in maestro");
@code{cpp}
xbt_dict_t Host::properties() {
return simgrid::simix::kernelImmediate([&] {
- simgrid::surf::HostImpl* surf_host =
- this->extension<simgrid::surf::HostImpl>();
- return surf_host->getProperties();
+ simgrid::kernel::resource::HostImpl* host =
+ this->extension<simgrid::kernel::resource::HostImpl>();
+ return host->getProperties();
});
}
@endcode
auto kernel_sync(F code) -> decltype(code().get())
{
typedef decltype(code().get()) T;
- if (SIMIX_is_maestro())
- xbt_die("Can't execute blocking call in kernel mode");
+ xbt_assert(not SIMIX_is_maestro(), "Can't execute blocking call in kernel mode");
- smx_actor_t self = SIMIX_process_self();
+ auto self = simgrid::kernel::actor::ActorImpl::self();
simgrid::xbt::Result<T> result;
simcall_run_blocking([&result, self, &code]{
{
if (!valid())
throw std::future_error(std::future_errc::no_state);
- smx_actor_t self = SIMIX_process_self();
+ auto self = simgrid::kernel::actor::ActorImpl::self();
simgrid::xbt::Result<T> result;
simcall_run_blocking([this, &result, self]{
try {
void notify_one();
void notify_all();
-
+
};
@endcode
simcall_cond_wait_timeout(cond_, lock.mutex()->mutex_, timeout);
return std::cv_status::no_timeout;
}
- catch (xbt_ex& e) {
-
+ catch (const simgrid::TimeoutException& e) {
// If the exception was a timeout, we have to take the lock again:
- if (e.category == timeout_error) {
- try {
- lock.mutex()->lock();
- return std::cv_status::timeout;
- }
- catch (...) {
- std::terminate();
- }
+ try {
+ lock.mutex()->lock();
+ return std::cv_status::timeout;
+ }
+ catch (...) {
+ std::terminate();
}
-
- std::terminate();
}
catch (...) {
std::terminate();
double duration, P pred)
{
return this->wait_until(lock,
- SIMIX_get_clock() + duration, std::move(pred));
+ simgrid::s4u::Engine::get_clock() + duration, std::move(pred));
}
@endcode
In addition, we wrote variations of some other C++ standard library
classes (`SimulationClock`, `Mutex`, `ConditionVariable`) which work in
the simulation:
-
+
* using simulated time;
* using simcalls for synchronisation.
This type of approach might be useful for other libraries which define
their own contexts. An example of this is
-[Mordor](https://github.com/mozy/mordor), a I/O library using fibers
+[Mordor](https://github.com/mozy/mordor), an I/O library using fibers
(cooperative scheduling): it implements cooperative/fiber
[mutex](https://github.com/mozy/mordor/blob/4803b6343aee531bfc3588ffc26a0d0fdf14b274/mordor/fibersynchronization.h#L70),
[recursive
@code{cpp}
template<class T>
class Result {
- enum class ResultStatus {
- invalid,
- value,
- exception,
- };
public:
- Result();
- ~Result();
- Result(Result const& that);
- Result& operator=(Result const& that);
- Result(Result&& that);
- Result& operator=(Result&& that);
bool is_valid() const;
- void reset();
void set_exception(std::exception_ptr e);
void set_value(T&& value);
void set_value(T const& value);
T get();
private:
- ResultStatus status_ = ResultStatus::invalid;
- union {
- T value_;
- std::exception_ptr exception_;
- };
+ boost::variant<boost::blank, T, std::exception_ptr> value_;
};
@endcode~
@endcode
-## Notes
+## Notes
[^getcompared]:
in the simulation which we would like to avoid.
`std::try_lock()` should be safe to use though.
-*/
\ No newline at end of file
+*/
