Loïc Lagadec, Damien Picard: Smalltalk Debug Lives in the Matrix. ESUG 2010, Barcelona, Spain

1. Smalltalk Debug Lives in the Matrix
Loïc Lagadec, Damien Picard
Loic.lagadec@univ-brest.fr

2. What Matrix?
“Flexible” hardware Hard to program
Time to market Hard to debug
Compute node i1
LUT LUT LUT
I1-i2
i2 E/S
µP
i1
LUT LUT
I1+i2
i2 LUT
Programmable
LUT LUT LUT interconnection

3. What Matrix?
“Flexible” hardware Hard to program
Time to market Hard to debug
Specific languages
Specific tools
Performances still
requires manual
tuning
EE skills required

4. State of the art debugging
Huge challenge

5. Touching the void
State of the art debugging
Huge challenge
Meet in the middle

6. Debug silver bullet
Observability
Controlability
Abstract analysis
Fast changes
Time to market
Multiple runs
Long cycles
Simulation is not
enough

7. Debug silver bullet
Observability
Controlability
Abstract analysis
Fast changes
Time to market
Multiple runs
Long cycles
Simulation is not
enough

8. Operate at-speed
Keep your speed-up alive
Multiple runs prohibit any over time penalty

9. Operate in-situ
Because only HW brings speed-up
Debug requires extra circuitry

10. Debugging facilities are circuits

11. Debugging facilities are circuits

12. Debugging facilities are circuits

13. Observe and monitor
Take decision
You cannot watch everything

14. Abstract analysis: semantic needed
From information to knowledge
Signals vs Variables, etc.
Composite pattern, polymorphism, etc.

15. From a technical point of view
?
 Synthesis 
Software abstraction Implementation in hardware
From D. Picard’s ESUG 2009 talk

16. Full observabiliy isn’t scalable
Focus on POI

17. Full observabiliy isn’t scalable
Focus on POI

18. Take control
Select your
Become a time traveller

19. Smalltalk debugger
Just fit approach
Run code and catch exception
Code hot replacement, variable update,
etc.
Step on or resume execution
Possible rollback
Multiple runs
Breakpoints update, earlier exception
Same conceptual behavior

20. Dodge bullets
Once the time has stopped
… just operate !

21. Bullet time explained
Bullet time
21

22. Conditional probes
Conditional probes offer the controlabily
that lacks in commercial tools
Observability can be gained at the cost
of adding some variable look-up wires
… But also using vendor’s tool such as
Chipscope

23. Decomposition
Red Pill Probes
Application
Application Inserted probe
(Generated)
Control panel
Active probes
Probes
inspector

24. RedPill Flow extends Biniou (HLS)
Application
Probe High-level
Insertion CDFG
Low-level
CDFG
Multi-Level
Simulator
Synthesis
Tools
Probed Netlist
Reconfigurable
Architecture
Biniou

25. Abstract analysis
Encapsulate circuit modules as smalltalk blocks
Enables soft and hard objects to
communicate
Delivers the power of Sunit to hardware

26. Abstract analysis (example)

27. Characterization tests & SUnit

28. How Many matrix?

29. Reboot the Matrix

30. Will you take the red pill?
HLS (Biniou) offers a path from HL
languages to circuits
Vendors tools offer observability
Red Pill offers controlability
Object encapsulation offers abstract
analysis and polymorphism.
Smalltalk debug definitively lives in the Matrix

31. Thank you for your attention
http://stiff.univ-brest.fr/BINIOU