Remote Function Invocation Running a Single Program On Multiple Computers

Thesis Single Program Single Computer Serial Processing

Antithesis Multiple Programs Multiple Computers Cooperate on Single Problem via Messages

Synthesis Single Program Multiple Computers

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

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

Programs Native Code Virtual Platform RFI exists

Developing Rexel Remote Execution Environment for Linux

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

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

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

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

Speed (1/2)

Speed (2/2)

Speed Overall Predictability

Consistency (1/2)

Consistency (2/2)

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

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

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

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

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

Solving Expressions Solved recursively Independently

Concurrent Solving

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

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