Real-time support for interactive multimedia applications
AbstractEmerging interactive multimedia applications, such as real-time visualizations, animations, on-line games, virtual reality, and video conferencing have low latency interactions and continuous high resource (e.g., CPU processing and network bandwidth) demands. The combination of latency sensitive interactions and high resource demands is challenging for best-effort platforms, such as the Internet, general-purpose operating systems and Web browsers because these platforms have no timing or resource guarantees and tend to favor high utilization. When demands exceed available resources, it is impossible to process all computations and data in a timely fashion resulting in diminished perceived quality (e.g., frame rate) and brittle real-time performance. The mismatch between application demands and available resources is observed to varying degrees in all resources including network, processing, and storage.
To deal with the volatility and shortage of resources, we build upon and extend the Priority-Progress quality adaptation model. Our approach enables applications to scale demands (up or down) based on available resources and to utilize the limited resources in processing the computations and data with more influence over perceived quality. We develop enhancement layers to improve timeliness and guarantee more consistent quality using quality adaptation while maintaining the strengths of the existing best-effort transports and execution platforms. DOHA, our execution layer, extends the Priority-Progress CPU adaptation to work in games and across multiple execution threads. The modified game has better timing, higher perceived quality, and linearly scalable quality with a small number of cores. Our transport layer, Paceline, introduces low latency techniques over TCP and exposes Priority-Progress adaptation as an essential transport feature improving upon TCP's end-to-end latency while preserving its fairness and utilization.Science, Faculty ofComputer Science, Department ofGraduat