Modeling of Time in Discrete-Event Simulation of Systems-on-Chip - - PowerPoint PPT Presentation

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Modeling of Time in Discrete-Event Simulation of Systems-on-Chip - - PowerPoint PPT Presentation

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jTLM Duration Applications Implementation Conclusion Modeling of Time in Discrete-Event Simulation of Systems-on-Chip Giovanni Funchal 1 , 2 and Matthieu Moy 1 1 Verimag (Grenoble INP) Grenoble, France 2 STMicroelectronics Grenoble, France

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SLIDE 1

jTLM Duration Applications Implementation Conclusion

Modeling of Time in Discrete-Event Simulation of Systems-on-Chip

Giovanni Funchal1,2 and Matthieu Moy1

1Verimag (Grenoble INP)

Grenoble, France

2STMicroelectronics

Grenoble, France Work partially supported by HELP ANR project

MEMOCODE, July 2011

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 1 / 22 >

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jTLM Duration Applications Implementation Conclusion

Outline

1

Transaction Level Modeling and jTLM

2

Time and Duration in jTLM

3

Applications

4

Implementation

5

Conclusion

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 2 / 22 >

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SLIDE 3

jTLM Duration Applications Implementation Conclusion

Outline

1

Transaction Level Modeling and jTLM

2

Time and Duration in jTLM

3

Applications

4

Implementation

5

Conclusion

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 3 / 22 >

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jTLM Duration Applications Implementation Conclusion

Modern Systems-on-a-Chip

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 4 / 22 >

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jTLM Duration Applications Implementation Conclusion

Modern Systems-on-a-Chip

Software Hardware

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 4 / 22 >

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jTLM Duration Applications Implementation Conclusion

Transaction-Level Modeling

(Fast) simulation essential in the design-flow

◮ To write/debug software ◮ To validate architectural choices ◮ As reference for hardware verification Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 5 / 22 >

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jTLM Duration Applications Implementation Conclusion

Transaction-Level Modeling

(Fast) simulation essential in the design-flow

◮ To write/debug software ◮ To validate architectural choices ◮ As reference for hardware verification

Transaction-Level Modeling (TLM):

◮ High level of abstraction ◮ Suitable for Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 5 / 22 >

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jTLM Duration Applications Implementation Conclusion

Transaction-Level Modeling

(Fast) simulation essential in the design-flow

◮ To write/debug software ◮ To validate architectural choices ◮ As reference for hardware verification

Transaction-Level Modeling (TLM):

◮ High level of abstraction ◮ Suitable for

Industry Standard = SystemC/TLM

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 5 / 22 >

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jTLM Duration Applications Implementation Conclusion

SystemC/TLM vs. “TLM Abstraction Level” SystemC TLM

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 6 / 22 >

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jTLM Duration Applications Implementation Conclusion

SystemC/TLM vs. “TLM Abstraction Level” SystemC TLM

Cycle accurate RTL Gate level TLM 2.0

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 6 / 22 >

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jTLM Duration Applications Implementation Conclusion

SystemC/TLM vs. “TLM Abstraction Level” SystemC TLM

Cycle accurate RTL Gate level TLM 2.0

?

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 6 / 22 >

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jTLM Duration Applications Implementation Conclusion

SystemC/TLM vs. “TLM Abstraction Level” SystemC TLM

Cycle accurate RTL Gate level TLM 2.0

?

δ-cycle Coroutine semantics Function calls Parallelism Clocks

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 6 / 22 >

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jTLM Duration Applications Implementation Conclusion

SystemC/TLM vs. “TLM Abstraction Level” SystemC TLM

Cycle accurate RTL Gate level TLM 2.0

?

δ-cycle Coroutine semantics Function calls Parallelism Clocks jTLM = this talk

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 6 / 22 >

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jTLM Duration Applications Implementation Conclusion

jTLM: goals and peculiarities

jTLM’s goal: define “TLM” independently of SystemC

◮ Not cooperative (true parallelism) ◮ Not C++ (Java) ◮ No δ-cycle

Interesting features

◮ Small and simple code (≈ 500 LOC) ◮ Nice experimentation platform

Not meant for production

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 7 / 22 >

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jTLM Duration Applications Implementation Conclusion

Outline

1

Transaction Level Modeling and jTLM

2

Time and Duration in jTLM

3

Applications

4

Implementation

5

Conclusion

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 8 / 22 >

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jTLM Duration Applications Implementation Conclusion

Simulation Time Vs Wall-Clock Time

Simulation time

10 20 30 40

Wall-clock time Time elapse Computation

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 9 / 22 >

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jTLM Duration Applications Implementation Conclusion

Time in SystemC and jTLM

SystemC jTLM A B P Q

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 10 / 22 >

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jTLM Duration Applications Implementation Conclusion

Time in SystemC and jTLM

SystemC jTLM A B P Q Process A: // computation f(); // time taken by f wait(20, SC_NS);

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 10 / 22 >

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jTLM Duration Applications Implementation Conclusion

Time in SystemC and jTLM

SystemC jTLM A B P Q Process A: // computation f(); // time taken by f wait(20, SC_NS); f() wait(20)

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 10 / 22 >

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jTLM Duration Applications Implementation Conclusion

Time in SystemC and jTLM

SystemC jTLM A B P Q Process A: // computation f(); // time taken by f wait(20, SC_NS); f() wait(20) Process P: g(); awaitTime(20); g() awaitTime

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 10 / 22 >

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jTLM Duration Applications Implementation Conclusion

Time in SystemC and jTLM

SystemC jTLM A B P Q Process A: // computation f(); // time taken by f wait(20, SC_NS); f() wait(20) Process P: g(); awaitTime(20); consumesTime(15) { h(); } g() awaitTime h()

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 10 / 22 >

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jTLM Duration Applications Implementation Conclusion

Time in SystemC and jTLM

SystemC jTLM A B P Q Process A: // computation f(); // time taken by f wait(20, SC_NS); f() wait(20) Process P: g(); awaitTime(20); consumesTime(15) { h(); } g() awaitTime h() i() j()

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 10 / 22 >

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jTLM Duration Applications Implementation Conclusion

Time à la SystemC: awaitTime(T)

By default, time does not pass ⇒ instantaneous tasks awaitTime(T) : let other processes execute for T time units Simulation time

10 20 30 40

Wall-clock time Time elapse Computation f(); // instantaneous awaitTime(20);

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 11 / 22 >

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jTLM Duration Applications Implementation Conclusion

Task with Known Duration: consumesTime(T)

Semantics:

◮ Start and end dates known ◮ Actions contained in task spread in

between

Advantages:

◮ Model closer to actual system ◮ Less bugs hidden ◮ Better parallelization

consumesTime(15) { f1(); f2(); f3(); } consumesTime(10) { g(); }

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 12 / 22 >

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jTLM Duration Applications Implementation Conclusion

Execution of consumesTime(T)

Slow computation

Simulation time

10 20 30 40

Wall-clock time Task starts Simulation time blocked Task finishes

Fast computation

Simulation time

10 20 30 40

Wall-clock time Task starts Computation ends Task finishes Rest of the platform drives time idle

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 13 / 22 >

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jTLM Duration Applications Implementation Conclusion

Outline

1

Transaction Level Modeling and jTLM

2

Time and Duration in jTLM

3

Applications

4

Implementation

5

Conclusion

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 14 / 22 >

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jTLM Duration Applications Implementation Conclusion

Exposing Bugs

Example bug: mis-placed synchronization: flag = true; awaitTime(5); writeIMG(); awaitTime(10); || while(!flag) awaitTime(1); awaitTime(10); readIMG(); ⇒ bug never seen in simulation

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 15 / 22 >

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jTLM Duration Applications Implementation Conclusion

Exposing Bugs

Example bug: mis-placed synchronization: flag = true; awaitTime(5); writeIMG(); awaitTime(10); || while(!flag) awaitTime(1); awaitTime(10); readIMG(); ⇒ bug never seen in simulation consumesTime(15) { flag = true; writeIMG(); } || while(!flag) awaitTime(1); awaitTime(10); readIMG(); ⇒ strictly more behaviors, including the buggy one

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 15 / 22 >

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jTLM Duration Applications Implementation Conclusion

Parallelization

P1 P2 P3 P4 jTLM’s Semantics Simultaneous tasks run in parallel

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 16 / 22 >

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jTLM Duration Applications Implementation Conclusion

Parallelization

P1 P2 P3 P4 jTLM’s Semantics Simultaneous tasks run in parallel Non-simultaneous tasks don’t

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 16 / 22 >

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jTLM Duration Applications Implementation Conclusion

Parallelization

P1 P2 P3 P4 jTLM’s Semantics Simultaneous tasks run in parallel Non-simultaneous tasks don’t Overlapping tasks do

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 16 / 22 >

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jTLM Duration Applications Implementation Conclusion

Parallelization

P1 P2 P3 P4 jTLM’s Semantics Simultaneous tasks run in parallel Non-simultaneous tasks don’t Overlapping tasks do Back to SystemC:

◮ Parallelizing within δ-cycle = great if you have clocks ◮ Simulation time is the bottleneck with quantitative/fuzzy time Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 16 / 22 >

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jTLM Duration Applications Implementation Conclusion

Outline

1

Transaction Level Modeling and jTLM

2

Time and Duration in jTLM

3

Applications

4

Implementation

5

Conclusion

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 17 / 22 >

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jTLM Duration Applications Implementation Conclusion

Time Queue and awaitTime(T)

Current instant P , Q, R Process P: f(); awaitTime(50); Process Q: h(); awaitTime(30); g(); awaitTime(30); Process R: i(); awaitTime(90);

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 18 / 22 >

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jTLM Duration Applications Implementation Conclusion

Time Queue and awaitTime(T)

Current instant Q, R awaitTime(50) P Process P: f(); awaitTime(50); Process Q: h(); awaitTime(30); g(); awaitTime(30); Process R: i(); awaitTime(90);

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 18 / 22 >

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jTLM Duration Applications Implementation Conclusion

Time Queue and awaitTime(T)

Current instant R P awaitTime(30) Q Process P: f(); awaitTime(50); Process Q: h(); awaitTime(30); g(); awaitTime(30); Process R: i(); awaitTime(90);

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 18 / 22 >

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jTLM Duration Applications Implementation Conclusion

Time Queue and awaitTime(T)

Current instant P Q awaitTime(90) R Process P: f(); awaitTime(50); Process Q: h(); awaitTime(30); g(); awaitTime(30); Process R: i(); awaitTime(90);

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 18 / 22 >

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jTLM Duration Applications Implementation Conclusion

Time Queue and awaitTime(T)

Current instant P Q R Time Elapse Process P: f(); awaitTime(50); Process Q: h(); awaitTime(30); g(); awaitTime(30); Process R: i(); awaitTime(90);

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 18 / 22 >

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jTLM Duration Applications Implementation Conclusion

Time Queue and awaitTime(T)

P Q R Current instant Process P: f(); awaitTime(50); Process Q: h(); awaitTime(30); g(); awaitTime(30); Process R: i(); awaitTime(90);

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 18 / 22 >

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jTLM Duration Applications Implementation Conclusion

Time Queue and awaitTime(T)

P R Current instant awaitTime(30) Q Process P: f(); awaitTime(50); Process Q: h(); awaitTime(30); g(); awaitTime(30); Process R: i(); awaitTime(90);

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 18 / 22 >

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jTLM Duration Applications Implementation Conclusion

Time Queue and consumesTime(T)

What about consumesTime(T) ?

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 19 / 22 >

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jTLM Duration Applications Implementation Conclusion

Time Queue and consumesTime(T)

Current instant P , Q, R

Process P: f(); consumesTime(50){ g(); } h(); Process Q: i(); awaitTime(30); j(); consumesTime(30){ k(); } Process R: l(); awaitTime(90);

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 20 / 22 >

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jTLM Duration Applications Implementation Conclusion

Time Queue and consumesTime(T)

Current instant Q, R consumesTime(50) P

Process P: f(); consumesTime(50){ g(); } h(); Process Q: i(); awaitTime(30); j(); consumesTime(30){ k(); } Process R: l(); awaitTime(90);

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 20 / 22 >

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jTLM Duration Applications Implementation Conclusion

Time Queue and consumesTime(T)

Current instant Q, R P

Process P: f(); consumesTime(50){

  • g();

} h(); Process Q: i(); awaitTime(30); j(); consumesTime(30){ k(); } Process R: l(); awaitTime(90);

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 20 / 22 >

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jTLM Duration Applications Implementation Conclusion

Time Queue and consumesTime(T)

Current instant R P awaitTime(30) Q

Process P: f(); consumesTime(50){

  • g();

} h(); Process Q: i(); awaitTime(30); j(); consumesTime(30){ k(); } Process R: l(); awaitTime(90);

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 20 / 22 >

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jTLM Duration Applications Implementation Conclusion

Time Queue and consumesTime(T)

Current instant P Q awaitTime(90) R

Process P: f(); consumesTime(50){

  • g();

} h(); Process Q: i(); awaitTime(30); j(); consumesTime(30){ k(); } Process R: l(); awaitTime(90);

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 20 / 22 >

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SLIDE 47

jTLM Duration Applications Implementation Conclusion

Time Queue and consumesTime(T)

Current instant P Q R Time Elapse

Process P: f(); consumesTime(50){

  • g();

} h(); Process Q: i(); awaitTime(30); j(); consumesTime(30){ k(); } Process R: l(); awaitTime(90);

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 20 / 22 >

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SLIDE 48

jTLM Duration Applications Implementation Conclusion

Time Queue and consumesTime(T)

P Q R Current instant

Process P: f(); consumesTime(50){

  • g();

} h(); Process Q: i(); awaitTime(30); j(); consumesTime(30){ k(); } Process R: l(); awaitTime(90);

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 20 / 22 >

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SLIDE 49

jTLM Duration Applications Implementation Conclusion

Time Queue and consumesTime(T)

P R Current instant consumesTime(30) Q

Process P: f(); consumesTime(50){

  • g();

} h(); Process Q: i(); awaitTime(30); j(); consumesTime(30){ k(); } Process R: l(); awaitTime(90);

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 20 / 22 >

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SLIDE 50

jTLM Duration Applications Implementation Conclusion

Time Queue and consumesTime(T)

P R Current instant Q

Process P: f(); consumesTime(50){

  • g();

} h(); Process Q: i(); awaitTime(30); j(); consumesTime(30){

  • k();

} Process R: l(); awaitTime(90);

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 20 / 22 >

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jTLM Duration Applications Implementation Conclusion

Time Queue and consumesTime(T)

P R Current instant Q Time Elapse

Process P: f(); consumesTime(50){ g(); } h(); Process Q: i(); awaitTime(30); j(); consumesTime(30){

  • k();

} Process R: l(); awaitTime(90);

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 20 / 22 >

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SLIDE 52

jTLM Duration Applications Implementation Conclusion

Time Queue and consumesTime(T)

P R Q Current instant

Process P: f(); consumesTime(50){ g(); } h(); Process Q: i(); awaitTime(30); j(); consumesTime(30){

  • k();

} Process R: l(); awaitTime(90);

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 20 / 22 >

slide-53
SLIDE 53

jTLM Duration Applications Implementation Conclusion

Outline

1

Transaction Level Modeling and jTLM

2

Time and Duration in jTLM

3

Applications

4

Implementation

5

Conclusion

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 21 / 22 >

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SLIDE 54

jTLM Duration Applications Implementation Conclusion

Perspectives

Summary

◮ Tasks with duration ◮ Exhibit more behaviors/bugs ◮ Better parallelization

Skipped from the talk (cf. paper)

◮ Tasks with a priori unknown duration ◮ jTLM’s cooperative mode

Perspectives

◮ Adapt the ideas to SystemC (ongoing, not so hard) ◮ Run-time Verification to explore schedules (science-fiction) ◮ Open-Source Release? Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 22 / 22 >

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SLIDE 55

jTLM Duration Applications Implementation Conclusion

Perspectives

Summary

◮ Tasks with duration ◮ Exhibit more behaviors/bugs ◮ Better parallelization

Skipped from the talk (cf. paper)

◮ Tasks with a priori unknown duration ◮ jTLM’s cooperative mode

Perspectives

◮ Adapt the ideas to SystemC (ongoing, not so hard) ◮ Run-time Verification to explore schedules (science-fiction) ◮ Open-Source Release?

Thank you! Questions?

Matthieu Moy (Verimag) Modeling of Time/jTLM MEMOCODE, July 2011 < 22 / 22 >