Quantitative Evaluation of Embedded Systems

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

MCM = 22ms S t 0 = 34ms A C B 26ms 30ms t 0 = 0ms t 0 = 8ms Latency = 10ms

MCM = 22ms S t 0 = 34ms A C B 26ms 30ms t 0 = 0ms t 0 = 8ms D Delay = 34ms 10ms 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 Delayed latency ≤ T output + E output + δ·μ - T input

ACB 26ms 30ms 10ms E 15ms

MCM = 22ms S A C B 26ms 30ms 0ms 8ms 0ms D Delay = 10ms E 15ms 34ms

Determine the MCM and choose a period μ ≥ MCM For each actor a initialize a start-time T a := 0 Repeat for each arc a—i—b : T b := T b max (T a + E a – i μ) until there are no more changes Repeat for each actor a: T a := min {all arcs a-i-b} (T b - E a + i μ) until there are no more changes Delayed latency ≤ T output + E output + δ·μ - T input