Performance Tuning Guide - EMC Community Network

Measuring Performance
Chapter 7
This chapter provides guidelines for measuring performance and includes the following topics:
• Measuring latency and throughput, page 69
• Measuring single user performance, page 71
• Running multi-user (load) tests, page 80
Measuring latency and throughput
Latency and throughput provide the two key Documentum system performance metrics. Latency
defines the minimum time required to get any kind of response, even one that requires no processing
time. Throughput defines the number of transactions the system can process per unit of time, 100
TaskSpace searches per minute, for example.
Single user and multi-user (load) testing comprise the approach for testing xCP performance. Single
user testing measures latency by capturing metrics for business transactions at the client tier (HTTP
request service times) or at the application server tier (Content Server RPC service times) on a quiet
system. Single user testing involves collecting and analyzing detailed trace files for DFC and/or
Oracle, and is performed before multi-user testing.
Multi-user testing builds on the single user testing by capturing service times for the same business
transactions used in single user testing, executed by multiple concurrent users. Multi-user testing
measures throughput by capturing "average" and "95th percentile" response times for a given
business transactions under a given user load while measuring coarse system statistics (CPU
utilization, network utilization, disk I/O, and so on). Multi-user testing response times can never
be any better than single user response times.
Single user testing can be used to measure the user experience from various locations (laptop via VPN
or remote facility, for example). User experience testing can account for network latency, browser
Javascript processing overhead, or other client machine activities such as virus scan, disk encryption,
or stateful firewalls. User experience testing use HTTP proxy tools (Charles, for example) to capture
HTTP requests and service times on the client browser machine. Load testing tools like WinRunner
(unlike LoadRunner) capture and measure the user experience but have to be carefully architected
to account for desired testing experience (network bandwidth, Javascript processing, virus scan,
disk encryption, stateful firewalls, and so on).
EMC Documentum xCP 1.0 Performance Tuning Guide 69