1. PROGRESS project: Quality of Service in In-Home Digital Networks System Architecture and Networking The approach we took was to provide a characterization of streaming applications execution to determine performance attributes and provide insight into best design practices for optimizing these attributes. The systems we analyze are streaming applications using the TriMedia Streaming Software Architecture (TSSA) and executing on a TriMedia device. 4. Validation – Number of Context Switches Calculation Affiliation 1) Eindhoven University of Technology Department of Mathematics and Computer Science HG 6.57, P.O. Box 513, NL-5600 MB, Eindhoven, The Netherlands 2) Philips Research NatLab Prof. Holstlaan 4, 5656AA Eindhoven, The Netherlands A Characterization of Streaming Applications Execution Author: M.A. Albu 1. Co-authors: Peter v.d. Stok 1,2, Johan Lukkien 1 About the Author Alina Weffers-Albu received her P.D.Eng. in Software Technology from the Department of Mathematics and Computer Science of the Eindhoven University of Technology (TU/e) in 2003. In July 2003 Alina started a Ph.D. project within the SAN group of the same department, in collaboration with Philips Research Laboratories Eindhoven. 2. TriMedia Streaming Software Architecture Typical execution scenario of a TSSA component  - the component gets 1 Full Packet from the input Full Queue,  - gets 1 Empty Packet from the input Empty Queue,  - performs the processing,  - recycles the input Full Packet by putting it in the output Empty Queue.  - uses the packet received from the input Empty Queue to store data to be transmitted to the next component by putting it in the output Full Queue. 5. Conclusions 1. Introduction T he goal of our work is the prediction and optimization of performance attributes to provide guaranteed and optimized Quality of Service (QoS) for interconnected real-time embedded systems. 3. Characterization of streaming applications execution Execution pattern of the stable phase is of importance: A TSSA media processing application - graph: Nodes: - software components Edges: - finite buffers (queues) that transport the data stream from one component to the next component in the graph.     Empty Queue Full Queue Empty Queue Component Processing code  Get Full PacketPut Full Packet Put Empty PacketGet Empty Packet EQ FQ EQ FQ C1C1 C2C2 CnCn … Hyperperiod Initialization Phase Stable Phase Finalization Phase Initialization phase: C 1 : executes until output FQ is filled => C 1 - Blocked (B). C 2 C 1 (B), C 2 C 1 (B), C 2 C 1 (B), until C 2 (FQ filled => C 2 (B))C 1 (B), C 3 C 2 (B)C 1 (B), C 3 C 2 (B)C 1 (B), until C 3 (FQ filled => C 3 (B))C 2 (B)C 1 (B) … C n-1 C n-2 (B)…C 1 (B), C n-1 C n-2 (B)…C 1 (B) until C n-1 ( FQ filled => C n-1 (B))C n-2 (B)…C 1 (B) Stable phase: C n C n-1 (B)…C 1 (B), C n C n-1 (B)…C 1 (B), … C1C1 C2C2 CnCn P(C 1 ) > P(C 2 ) > …> P(C n ) … The execution sequence in the initialization phase determines the repetitive execution pattern during the stable phase. The priority assignment determines the execution sequence during the initialization phase. FRead VDecSSEVO P(FRead) > P(VDec) > P(SSE) > P(VO) NCS_hyperperiod(FRead) = 5, NCS_hyperperiod(VDec) = 9, NCS_hyperperiod(SSE) = 8, NCS_hyperperiod(Vo) = 8. Total NCS_hyperperiod = 30. NCS_StablePhaseCalculated = 900; NCS_StablePhaseMeasured = 895; Experiment Streaming chain consisting of: FRead – file reader VDec – video decoder SSE – sharpness enhancement VO – video renderer FQ EQ FQ FRead VDecSSEVO FQ EQ Goal Number of context switches (NCS) calculation Components dependencies Results Characterization of streaming applications execution Prediction for performance quality attributes Validation by calculating the NCS occurring during the execution of a streaming chain. Future work Providing best design practices for optimizing performance quality attributes.