1. Design Space Exploration
Wouter Caarls
Max Planck Institute for Biophysical Chemistry
EVA project meeting,

2. What is DSE?
Explore the space of possible processing architectures in order to determine an optimal design for solving a certain problem.
What is optimal?
May also include different algorithms for solving the problem
Is not necessarily automated

3. Why DSE? Tailor architecture to program, instead of other way around
Consider many architectures, instead of just what’s familiar
Application may change
Product requirements
Implementation/algorithms

4. How does it work? Take an initial set of architectures
Predict the performance of the application on those architectures
Evaluate the performance according to some evaluation criterion. If satisfied, go to 5
Find new architectures based on the best scoring ones and go to 2
Choose an architecture
Execute the application on the chosen architecture

5. 1. Generating initial architectures
Random
Increasing complexity
Decreasing complexity

6. 2. Performance prediction
Must work for many possible architectures
Different processor architectures
Processor parameters
(Heterogeneous) multiprocessing
Interconnect
Implementation strategies
OS parameters (mapping & scheduling)
For each function
Benchmarking
Annotation
For the application
Discrete event simulation

7. 3. Evaluation Criteria Optimization strategy Speed Power consumption
Cost
Optimization strategy
Some minimal requirements are often known beforehand
But tradeoff must always be made manually
Requires optimization of a tradeoff (Pareto) curve

8. Optimization strategy Constrained single objective
performance
cost
minimum
performance

9. Optimization strategy Multiobjective tradeoff iteration
performance
cost

10. Optimization strategy Strength Pareto
performance
cost

11. 4. Exploration Hill climbing Simulated annealing
Evolutionary algorithm

12. 5. Selection
Ultimate tradeoff made by human

13. 6. Execution Different processor parameters Multiple processors
High-level programming language
Multiple processors
Parallel language
Multiple processing paradigms
Multiple implementations
Very high level language