What are the performance enhancement we can do ??
like if one interface is taking long time to complete what parameter we have to check and what we can do to achieve better performance
and overall what we can do to improve ODI performance ??
There is no ODI parameter that you can really tweak to increase overall performance (or else it would be enabled by default). So it really depends on your needs.
Most of the job is not done by ODI itself but by your underlying DB. ODI is an ELT and not an ETL.
So as Bhabani said, the best to do is to check the generated code and change your interface or your KM if needed.
For example if you think you need to run stats, you can do something like this : http://www.business-intelligence-quotient.com/?p=1754
You can also disable indexes before the integration steps and rebuild it afterwards.
Hope it helps.