Why performance is

a key factor?

Some e-commerce consultants cite an attention span on the order of eight seconds as the threshold for abandoning a slow retail site.
Where broadband connections are the norm, pages that don't appear instantly stand a good chance of never being seen: slow pages might as well be no pages.
Systems can only be designed to meet performance goals if those goals have been identified. Determine what range of response times will be acceptable.
Try to understand the performance impacts of your design decisions.

We got a valuable

experience in the

following aspect...

1) Include budget for performance management.
2) Create an internal performance experts.
Set the performance requirements in the specifications from the begining....
3) Include a performance focus in the analysis.
Require performance predictions from the design.
4) Create a performance test environment.
Test a simulation or skeleton system for validation.
5) Integrate performance logging into the application layer boundaries.
6) Performance test the system at multiple scales and tune using the resulting information
7) Deploy the system with performance logging features.

...And concrete

hands-on

experience...

Set performance goals before development starts.
If supporting clients with slow connections, consider compressing data for network communication.
Minimize the number of network round trips required by the application.
For applications to scale to many users, minimize the amount of shared memory that requires updating.
Cache data to minimize lookup time, though this can reduce scalability if locks are required to access the cache.