simgrid::kernel::actor::SimcallObserver* observer);
XBT_PUBLIC void simcall_run_blocking(std::function<void()> const& code,
simgrid::kernel::actor::SimcallObserver* observer);
+XBT_PUBLIC void simcall_run_object_access(std::function<void()> const& code,
+ simgrid::kernel::actor::ObjectAccessSimcallItem* item);
namespace simgrid {
namespace kernel {
/** 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.
+ * 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,
return result.get();
}
+/** 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 occure 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 <class F> typename std::result_of_t<F()> 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<F>(code)();
+
+ // If called from another thread, do a real simcall. It will be short-cut on need
+ using R = typename std::result_of_t<F()>;
+ simgrid::xbt::Result<R> result;
+ simcall_run_object_access([&result, &code] { simgrid::xbt::fulfill_promise(result, std::forward<F>(code)); }, item);
+
+ return result.get();
+}
+
/** Execute some code (that does not return immediately) in kernel context
*
- * This is very similar to simcall() right above, but the calling actor will not get rescheduled until
+ * 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.
simcall_blocking(std::forward<F>(code), static_cast<SimcallObserver*>(observer));
return observer->get_result();
}
+// compact namespaces are C++17 and this is a public header file so let's stick to C++14
} // namespace actor
} // namespace kernel
} // namespace simgrid
-
#endif
