1. CS 584 Lecture7 Assignment -- Due Now! Paper Review is due next week.
JPDC
IEEE Concurrency
IEEE Transactions on Parallel and Distributed Systems
Conference Proceedings (see me)

2. Review Partition Communication Agglomeration Mapping
Place tasks on physical processors

3. Floorplan Optimization
VLSI Design
Computation used in many stages
Verify Correctness of Circuit Design
Circuit Layout
Circuit Test Pattern Generation

4. VLSI Design Stages
Generate a set of indivisible cells (rectangular blocks)
Use interconnection information for relative placement
Place cells with goal of optimizing the total area.
Floorplan optimization

5. Floorplan Optimization
Cells have different sizes and can be in a few different configurations.

6. Floorplan Optimization
Relative placements of the cells is represented by two graphs G and H
Up-Down
Left-Right

7. Floorplan Optimization
Using the G and H graphs we can generate alternative floorplans

8. Floorplan Optimization
Identify the configuration with the lowest area.
Explore a search tree representing all configurations
Exhaustive search infeasible
20 cells with 6 configurations each
620 ~ 4 x 1015 nodes

9. Branch and Bound Search
Reduces the number of nodes searched.
Keep track of the best solution
Prune the search by not expanding nodes whose solution is worse than the best known solution.

10. Floorplan Optimization
Place A
Place B
Place C

11. Parallelization
Branch and Bound search is the computational effort to be parallelized.
Irregular computational structure
Pruning introduces
Search order management
Propagation of global knowledge

12. Partition No obvious domain to decompose. Functional decomposition
Each search tree node explored by a different task
Wavefront
Only tasks on the wavefront can execute concurrently.

13. Communication All tasks must have best known solution. Trade-off
benefits of always having best solution
communication costs
Can use centralized scheme or hierarchical refinement

14. Agglomeration
A large search space can generate a huge number of tasks.
Create a new task for each node of the tree until we reach a certain point

15. Mapping Task scheduling algorithm
Workers request tasks and generate tasks to be worked on by others
Find a mapping that works with the agglomeration scheme.

16. Mapping Strategies Central manager Replication with cyclic mapping
Generates coarse grain tasks
Replication with cyclic mapping
Everybody expands tree
Everybody knows their responsibility
Hierarchical
Each node manages its subtree

17. PCAM Design Summary Partition problem into small tasks
Organize the necessary communication.
Agglomerate to decrease communication
Map tasks to processors
Pay attention to Performance!