Quantitative Evaluation of Embedded Systems

10ms A C B 30ms

Scr1 Scr2 Scr3Scr4 Scr5 Scr6Scr7 Detect CFEnSync FFEnCE Hdemod Pdemod Hdecode Pdecode MacCRC MacAnalyse BuildHeader AckCode AckMode CodeHeader ModHeader O.Moreira, F. Valente, M.Bekooij, “Scheduling multiple independent hard-real-time jobs on a heterogenous multiprocessor”, in Proceedings of the 7 th ACM & IEEE International conference on Embedded Software. EMSOFT 2007, pp , 2007

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

10ms A C B 30ms

10ms S A C B 30ms Press pause to calculate the MCM and a periodic schedule for it!

MCM = 20ms S 10ms t 0 = 10ms A C B 10ms 30ms t 0 = 0ms t 0 = 10ms

MCM = 20ms S 10ms t 0 = 10ms A C B 10ms 30ms t 0 = 0ms t 0 = 10ms Latency =

MCM = 20ms S 10ms t 0 = 10ms A C B 10ms 30ms t 0 = 0ms t 0 = 10ms Latency =

μ = 30ms S 10ms t 0 = 0ms A C B 10ms 30ms t 0 = 0ms Latency =

Given a dataflow graph with execution times E a Determine the MCM and choose a period μ ≥ MCM Determine start-times T a of a periodic schedule Determine the minimum number δ of tokens between input and output Latency ≤ T output + E output + δ·μ