1. Presented by Deepak Srinivasan Alaa Aladmeldeen, Milo Martin, Carl Mauer, Kevin Moore, Min Xu, Daniel Sorin, Mark Hill and David Wood Computer Sciences Department, University of Wisconsin-Madison & Department of Electrical and Computer Engineering, Duke University

2. Motivation DBMS and web servers are Commercial Workloads, which are growing in popularity Lots of services rely on them, and thus it’s important to validate Validate Execution-based simulator Hardware Prototypes Analytic Models Getting multi-million dollar multi-processor servers is probably too high a price tag for research groups testing workloads

3. Details Trying to test simulation on a $2000 PC instead 1 st Goal: Good approximation of workloads Scaling and fine tuning benchmarks which led to the Wisconsin Commercial Workload Suite Online Transaction Processing (OLTP), Java Middleware, Static Web Content Server, Dynamic Web Content Server Made several improvements in OLTP to improve its performance (12x improved) Allowed for smaller PC to have similar throughput to that of the servers

4. More Details 2 nd Goal: Reasonable Simulation Times Cutting Down Warm-Up Times – SIMICS and Checkpoints Measurement Interval and How to Determine Performance – Cycles/Transaction Short Simulation Variability – Average Multiple Trials with Random Memory Latency Times

5. Even More Details 3 rd Goal: Having Enough Timing Detail Hard to Simulate for Multiprocessor chips – Need to Simulate every piece of Architecture Extending SIMICS with 2 Timing Simulators Memory Simulator – Time-consuming Components are simulated exactly, others are approximated Detailed Processor Timing – Timing-First Simulation – Implemented with Timing and a Functional Simulator

6. Evaluation – Case Study Bash

7. Conclusions Adapting Simulators usually used in commercial servers for small PCs is hard but possible Ran into several difficulties including: Scaling the Workloads while keeping them similar Measuring Performance for a Multiprocessor System Keeping Appropriate Timing Detail The need to look at the Most Relevant workloads

8. Questions Is this evaluation technique all that credible without showing a comparison between the real benchmarks running compared to these condensed single PC simulations? Is using a small set of 4 benchmarks in the Wisconsin Commercial Workload Suite enough? Could Cloud Computing and cheap clusters be used as an alternative to this small PC simulation approach? Which approach you think research groups would prefer?