1. Remote Function Invocation
Running a Single Program
On Multiple Computers

2. Thesis
Single Program
Single Computer
Serial Processing

3. Antithesis Multiple Programs Multiple Computers
Cooperate on Single Problem via Messages

4. Synthesis
Single Program
Multiple Computers

5. Raises Questions Existing mechanisms? Message-passing necessary?
Comparison of Metrics?
Anything we can exploit? Use?

6. Objectives Develop the mechanism Benchmark RFI Demonstrate:
Running existing program on cluster
Exploitation of new opportunities presented by RFI

7. Programs
Native Code
Virtual Platform RFI exists

8. Developing Rexel
Remote Execution Environment for Linux

9. Node Setup Simple Comms Store libfile.so Register function
Call function

10. Function Calling Few major problems Trade-offs acceptable
Uses dlopen() and dlsym()
Uses Libffi for calling convention

11. Usage Usage (mostly) automatic Needs runtime linkage librexelmaster.so
Configured exclusively from config files

12. Test Setup Benchmarked against MPI Setup carefully controlled
System representative of cloud providers
Problem-space exhaustion

13. Speed (1/2)

14. Speed (2/2)

15. Speed Overall Predictability

16. Consistency (1/2)

17. Consistency (2/2)

18. Summary Rexel MPI Quicker at lots of smaller problems
Slower when number of repeated calls increase
Predictable and consistent throughout
Slower when problem is divided into tiny chunks
Faster as problem-size of each chunk grows
Unpredictable with tested criteria

19. Future? Rexel MPI Performance improved towards the end
Consistency improved towards the end

20. Running SQLite (1/2) SQLite: Small standalone database
Has c/line interface
Stores all data in a single file

21. SQLite (2/2) Run in LD_PRELOAD environment Unaware of Rexel
Mixed results
Successfully wrote files
Nodes could not return errors

22. Partial Shared-Memory
Expressions represented as trees
Leaf nodes are operands
Branch nodes are operators

23. Solving Expressions
Solved recursively
Independently

24. Concurrent Solving

25. Research Answers Mechanisms exist
Replacement possible for both shared-mem and MPI
Large effects on software design
Multiple opportunities to exploit

26. Future Opportunities Can have an impact on program design
Quorum Solving
Fine-grained Unit-testing
More???