HW-OSQM: Reducing the Impact of Event Signaling by Hardware-Based Operating System Queue Manipulation

System-on-chip integrate an increasing amount of processing elements and on-chip communication is of particular importance. Rising communication rates with varying delays require efficient techniques to signal events related to the on-chip communication to the application software. While latencies are commonly hidden by multithreading, the signaling of events is usually done by polling or interrupts. With rising rates of such events the classic techniques expose an increasing software overhead that becomes significantly important. In this paper we present the concept of hardware-based operating system queue manipulation (HW-OSQM) to offload the process of event signaling. The concept is implemented as a flexible hardware accelerator which integrates with the communication hardware and autonomously manipulates the queue data structures of the operating system. It eliminates the associated software overhead and utilizes small additional resources while allowing for the required flexibility. The performance improvement shows that HW-OSQM can nearly eliminate any overhead in software.