A QoS-aware I/O mechanism for jitter-free multimedia playing in smart devices

As multi-tasking has become the common feature of modern smart devices, providing QoS (quality of service) guarantees for heterogeneous applications becomes challenging. For example, if a real-time application like a movie player is executed simultaneously with other applications, jitters may be experienced due to resource contention among the concurrent processes. This paper presents a novel I/O mechanism to provide jitter-free multimedia playing in smart devices. To this end, the I/O paths of smart devices were explored and two sources of unpredictable latency were discovered. The first one is the garbage collection overhead of flash memory and the second one is the non-preemptive scheduling used in the software platform of smart devices. This paper resolves these problems by adopting non-volatile memory as the storage of real-time applications, and then performing non-blocking I/O for them. This mechanism completely prevents all possible run-time delays due to the interferences of other processes, providing QoS-guaranteed services for real-time applications. Tracedriven simulations show that the proposed scheme reduces the deadline miss ratio of a movie player by 40% on average.