Frequently Asked Questions
About Benchmarking with Web Polygraph

Duane Wessels

1. About Web Polygraph

2. Compiling Polygraph

• 2.1 I had a hard time compiling Polygraph 2.5.0 on Redhat 6.2 Linux

3. Running a Polygraph Test

• 3.1 polymon (v2.5.1) dumps core on Linux
• 3.2 During PolyMix-3, the clients are in the fill phase, but the servers are in the dec1 phase
• 3.3 PolyMix-2 fill phase cachable was 100%; why is it 80% for PolyMix-3?
• 3.4 Can I run a test with just one IP address per machine?
• 3.5 The PolyMix-3 working set size is much larger than PolyMix-2?
• 3.6 Can I run more than 1000 robots on a single machine?
• 3.7 What is the effect of simply removing a phase from the schedule?
• 3.8 How can I calculate the fill phase duration for a PolyMix-3 test?
• 3.9 How does the downtime test work?

4. PolyMix-3 IP Addressing

• 4.1 Flat vs Routed configuration
• 4.2 IP Address Assignment
• 4.3 How do I configure IP addresses for PolyMix-3?
• 4.4 Do clients and servers have a default route?
• 4.5 Can I use the proxy as my router?
• 4.6 In a routed test network, where does the monitoring PC go?

5. Interpreting Results

• 5.1 What are xact.level.mean, wait.level.mean, err xact.count?
• 5.2 Why is PolyMix-3 offered hit ratio not 55%?
• 5.3 gnuplot: Cannot open load file '-persist'

6. Polygraph Inner Workings

• 6.1 What is nmt?
• 6.2 What controls the number of open sockets, as shown in the last column of Polygraph's console output?
• 6.3 What can you tell me about reply sizes?

7. About the Third Cache-Off

• 7.1 What is the timeline for the Cache-Off?
• 7.2 Where is the Third Cache-Off being held?
• 7.3 For soft entry into the third cache-off event, you state that you require an auto-generated Polygraph report. What does that mean?
• 7.4 Why do you require the auto-generated report?
• 7.5 Cache Filling
• 7.6 Participation Fees
• 7.7 When are the results going to be made public?

8. Testing Environment

• 8.1 What do you use to sync time on your FreeBSD boxes?
• 8.2 How can I use NTP to synchronize my system clocks?

9. Web Traffic Workloads and Characterization

• 9.1 Whats the average size of a document?

10. TCP Maximum Segment Lifetime

• 10.1 MSL with Windows 2000

11. Lying

• 11.1 Can you please give me some information on why I failed?

12. About this Document