1. ITEA 2 – 09033: TIMMO-2-USE Timing Model – Tools, algorithms, languages, methodology, USE cases 2012-09-24..25AMST Workshop - BerlinSlide 1 Modeling timing constraints, parameterized and multi-clock systems in TADL2 Johan Nordlander, Chalmers University of Technology

2. System models & constraints 2012-09-24..25AMST Workshop - BerlinSlide 2 A system model: Industry objective: specify / characterize / verify models using constraints logical... resource usage... cost... timing... structural...

3. TADL2 (Timing Augmented Description Language) 2012-09-24..25AMST Workshop - BerlinSlide 3 A language of timing constraints (and timing constraints only) TADL2 Model Constraints Connecting points: the events exposed by a system model Delay... Periodic...

4. Events & occurrences 2012-09-24..25AMST Workshop - BerlinSlide 4 For each execution / simulation / prediction of a system, every event occurs a some points in time. Model time TADL2 constraints put demands on the relative placement of such occurrences

5. Source-to-target delay What if source repeats? Can multiple target occurrences match? Are stray target occurrences allowed? The need for semantic precision 2012-09-24..25AMST Workshop - BerlinSlide 5 But what about jitter? What if jitter > period? What if repetition stops? Is jitter meaningful here too? Same as upper-lower difference? Accumulating vs. non-accumulating drift? Some well-known occurrence patterns: Periodic repetition Sporadic repetition

6. DelayConstraint 2012-09-24..25AMST Workshop - BerlinSlide 6 DelayConstraint (source, target, lower, upper)   x  source :  y  target : lower ≤ y – x ≤ upper time source target lower upper duplicate and stray occurrences allowed

7. StrongDelayConstraint 2012-09-24..25AMST Workshop - BerlinSlide 7 StrongDelayConstraint (source, target, lower, upper)   i :  x : x = source(i)   y : y = target(i) : lower ≤ y – x ≤ upper time source target lower upper 123 123 duplicate and stray occurrences disallowed (lock-step enforced)

8. ReactionConstraint 2012-09-24..25AMST Workshop - BerlinSlide 8 time minimum maximum stimulus response scope ReactionConstraint ( scope, minimum, maximum )   x  scope.stimulus :  y  scope.response : x.color = y.color  (  y’  scope.response : y’.color = y.color  y ≤ y’)  minimum ≤ y – x ≤ maximum only first related response of interest

9. TADL2 constraint overview 2012-09-24..25AMST Workshop - BerlinSlide 9 DelayConstraint (source, target, lower, upper) StrongDelayConstraint (source, target, lower, upper) RepetitionConstraint (event, lower, upper, span, jitter) SynchronizationConstraint (event, tolerance) StrongSynchronizationConstraint (event, tolerance) ExecutionTimeConstraint (start, stop, preempt, resume, lower, upper) OrderConstraint (source, target) ComparisonConstraint (leftOperand, rightOperand, operator) SporadicConstraint (event, lower, upper, jitter, minimum) PeriodicConstraint (event, period, jitter, minimum) PatternConstraint (event, period, offset, jitter, minimum) ArbitraryConstraint (event, minimum, maximum) BurstConstraint (event, length, maxOccurrences, minimum) ReactionConstraint (scope, minimum, maximum) AgeConstraint (scope, minimum, maximum) OutputSynchronizationConstraint (scope, tolerance) InputSynchronizationConstraint (scope, tolerance) + mode-dependency parameter (optional)

10. ... but quite ok when restricted to mode M! M A mode-dependent DelayConstraint 2012-09-24..25AMST Workshop - BerlinSlide 10 time source target lower upper Not satisfied overall... start(M) stop(M) (a mode is defined by its start- and stop-events)

11. M A borderline mode-example 2012-09-24..25AMST Workshop - BerlinSlide 11 time source target lower upper start(M) stop(M) Should this trace be accepted by the mode-dependent DelayConstraint? There’s no matching target occurrence inside M... TADL2 thus chooses to answers yes! (the optimistic assumption)... but a matching occurrence is still possible outside M (where we don’t look!)

12. 2012-09-24..25AMST Workshop - BerlinSlide 12 Revision History Do not delete this slide! RevisionDateDescription 0.12012-08-31Initial Draft

13. 2012-09-24..25AMST Workshop - BerlinSlide 13 Notepad Do not delete this slide!