1. Three Questions To Ask About Clusters
Jeffrey K. Hollingsworth
Department of Computer Science
University of Maryland, College Park, MD 20742

2. What goes bump in the night on the cluster?
Can I get Performance within X% for two consecutive runs on the same data and cluster?
What goes bump in the night on the cluster?
OS Processes
Power/Heat Scaling on the processor
What changes when upgrades happen?
Operating System
Libraries
Hardware
Open Question: What value of X is right?
1%, 5%, 10%, 100%?

3. When Can I Stop Caring About the Network Topology (or Technology)?
Range Of Answers:
Today -> Never
Many Computational Scientists Don’t Care Now
Many CS Researchers Still Publish on this topic
No Fair making the MPI stack slow to make this possible

4. How Much Time will I Save with your new Language and at what cost?
Programmer Effort
Often Today: Trust me it will be easier: Threads, HPF, Transactional Memory
Need: Rigorous Study of benefits of features
Performance
How much performance to give up for easier programming?