1 / 11

Quantitative Evaluation of Embedded Systems

This paper evaluates the latency of periodic sources in embedded systems, particularly within Software-Defined Radio (WLAN) applications. It discusses methods for calculating the minimum cycle time (MCM) and establishing periodic schedules, emphasizing the importance of synchronization in multi-actor systems. It features a detailed analysis of latency behavior, providing insights into how delays in one component can propagate through the system. The evaluation is based on a dataflow graph model, and practical implications for real-time applications in embedded environments are discussed.

leena
Télécharger la présentation

Quantitative Evaluation of Embedded Systems

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Quantitative Evaluation of Embedded Systems Latency for a periodic source

  2. Latency for a periodic source A C B 30ms 10ms 10ms

  3. Software-Defined Radio (W-LAN) Scr1 Scr6 Scr7 Scr2 Scr5 Scr3 Scr4 BuildHeader ModHeader Pdemod Pdecode CodeHeader Hdemod CFEnSync FFEnCE Detect O.Moreira, F. Valente, M.Bekooij, “Scheduling multiple independent hard-real-time jobs on a heterogenous multiprocessor”, in Proceedings of the 7th ACM & IEEE International conference on Embedded Software . EMSOFT 2007, pp. 57-66, 2007 Hdecode AckMode MacCRC AckCode MacAnalyse

  4. Software-Defined Radio (W-LAN) * Disclaimer: this is just an illustration. The actual deployment of a W-LAN gives a graph that is too complicated to draw.

  5. Latency for a periodic source A C B 30ms 10ms 10ms

  6. Latency for a periodic source Press pause to calculate the MCM and a periodic schedule for it! A C B Delaying one actor will delay them all! 30ms S 10ms 10ms

  7. Latency for a periodic source t0 = 0ms A C B t0 = 10ms t0 = 10ms 30ms S 10ms MCM = 20ms 10ms

  8. Latency for a periodic source t0 = 0ms A C B t0 = 10ms t0 = 10ms 30ms S Latency = 10ms MCM = 20ms 10ms

  9. Latency for a periodic source t0 = 0ms A C B t0 = 10ms t0 = 10ms 30ms S Latency = 10ms MCM = 20ms 10ms

  10. Latency for a periodic source t0 = 0ms A C B t0 = 0ms t0 = 0ms 30ms S Latency = 10ms μ = 30ms 10ms

  11. Calculating a latency bound • Given a dataflow graph with execution times Ea • Determine the MCM and choose a period μ ≥ MCM • Determine start-times Ta of a periodic schedule • Determine the minimum number δ of tokens between input and output • Latency ≤Toutput+ Eoutput + δ·μ

More Related