Best Practices in Developing High Performance Java ApplicationsA Perspective

Keynote at Silicon India

Rajgopal KishoreVice President and Global Head of BI & Analytics,

HCL Technologiesrkishore@hcl.in

rkishore9@gmail.com

Agenda

• Business Implication of System Performance

• Understanding Performance Requirements

• Sharing Some War Stories

• Best Practices

Business Implications of System Performance

• We all want a nice user experience

• We won’t tolerate slow pages (we have options); lesser still any downtime– 500 ms slower = 20% drop in traffic (Google)– 100 ms slower = 1% drop in sales (Amazon)

• Slower Warehouse management system – lower warehouse throughput!

• Any downtime in a trading system - $m lost

What is Performance? Is a subset of NFR…

• On-line applications -– Response time– Maintaining response time with increasing load –

scalability– Throughput– Handles user expectations/frustration– Availability

• Batch applications– Runs in the batch window – which is constantly shrinking!– Does not slow down other on-line work to an

unacceptable level

Biggest Cause of Performance Failures..

• Not understanding performance requirements (implicit, explicit, real, or expectation)

• Not setting expectations early enough

• Not understanding and explaining trade-offs between performance and $ (infrastructure), and time

Performance Requirements Capture – Sample

• The application will be optimized for high throughput. Traffic is to be tested for 250 concurrent users and 24/7 operations

• All simple transactions will have a response time of less than 5 seconds. Complex transactions will have a response time of 15 seconds

• The response time of all the pages would be less than 3 seconds

Consequently …

• Performance requirements captured are insubstantial; Work pattern and user behavior is not understood

• Infrastructure is suggested with out any basis

• No performance benchmarking done till the system integration phase of the project

• Benchmarking goals are not defined

What are Performance Requirements? - Multiple dimensions

• Infrastructure model– Boxes, routers, IP splitters, CPUs, RAM, bandwidth

• Transaction model– Transaction arrivals rates, think time, variation across the day

• External transaction model– Any messages, file uploads

• Data retention model– # years, hot, warm and cold areas, read-only or read-write

Some War Stories

Deathcare Major in the US …

• 15000 users• Complex application• Low bandwidth network – 128K• 7 seconds response time needs – set after a

discussion

Major Retailer …

• Large and complex application for assortment planning

• Board level visibility

Large fashion Retailer…

• Big brand• Wanted a 2 second response time for a

planning application

At a mid size Telecom company…

• Need to “validate” capacity plan of their boxes for a MLM solution roll-out

Summarizing Some Best Practices in development high performance apps…

What you will not get on the Internet

Best Practices …

• Understand, set and control expectations.

• Always attempt to understand real business need as opposed to articulated performance requirements

• Big picture first – infrastructure capacity planning

• Then optimize the application – create an app where the only bottleneck is the infrastructure …

Best Practices …

• Abstraction is not good for performance …. Including Virtualization!!!

• Do not use the same APIS for batch and on-line programs

• Early stage performance prototyping….

Questions!