On the Integration of Real-time Asynchronous Event Handling Mechanisms with Existing Operating System Services

This paper presents an asynchronous event handling mechanism for real-time applications that leverages existing system services in COTS systems. In our implementation, event dispatching is initiated within bottom-half interrupt handling routines, in order to support predictable, safe, and efficient event handling functionality at user-level. We compare our asynchronous I/O mechanism with existing user-level approaches, such as the GNU C library implementation of the AIO API and the Linux signal abstraction. Using a user-level sandboxing scheme for asynchronous event handling, results show that network receive events can be dispatched in less than 15 microseconds using commodity hardware components. We show that the proposed architecture significantly outperforms the above mentioned user-level asynchronous I/O mechanisms and provides more flexibility than available hard real-time extensions.