+

Why “Average” Response Time is not a right measure of your web application's performance?

By- Nishant Verma

+For the next 15 minutes

n  Web Application Performance Testing

n  Average Response Time

n  Solution to Average Response Time

n  Beyond Average Response Time

n  Questions

+Web Application Performance Testing

+Web Application Performance Testing

How to do

Design Test/Scenarios

Establish Performance Acceptance

Criteria

Identify Environment

Execute Test

Analyze Reports / Tune/

Retests

What we collect

Response Time

Throughput

CPU Utilization

Memory

+Average Response Time

n  Response Time is defined as the time it takes for each Web page to load.

n  How we capture? n  Hit the server with a specified number of user (could be in pattern)

and then capture the response time of the server.

n  Refer the plot of ART on next page.

+Average Response Time

0

100

200

300

400

500

600

Page 1 (in ms)

Page 2 (in ms)

Page 3 (in ms)

+Problems with Average Response Time

n  It’s a bad way of tracking website performance.

n  It doesn’t indicate or hint about the outliers.

n  We tend to average the number of samples than the quantity itself.

n  It represents a distorted picture in case of exceptional scenario with extremely high response time.

What we need?

+Apdex

n  Created by Peter Sevcik of Apdex Alliance (apdex.org).

n  How is it calculated?

n  ApdexT = (# Satisfied requests + # Tolerating requests / 2)

(# Total requests)

APDEX: Application Performance Index

+How it scores over Average Response Time

n  It help takes us Go-No-Go decision.

n  It’s doesn’t hide outliers. It yells the number of users affected by the problem.

n  It doesn’t get distorted when there are extremely high response times.

n  It’s a measure towards Satisfaction score and can be derived based on threshold. It’s not a fix number.

+One last thing…

Load Testing

Stress Testing

Soak Testing

Performance Tuning

+Some Useful Readings

n  http://apdex.org/

n  http://en.wikipedia.org/wiki/Apdex

n  http://www.apdex.org/overview.html

n  https://newrelic.com/docs/site/apdex

n  https://newrelic.com/docs/site/apdex-dissatisfaction