Hi Mainak,
I agree with Gopi. It's tough to track the issues in one thread. You can keep this open but use a different thread for non-performance related issues.
Based on experience, you can resolve most of the issues by simply putting a breakpoint on:
/SAPTRX/EVENT_MGR_COMMUNICATE or /SAPTRX/BAPI_EH_POST -> for EH creations/Updates
/SAPTRX/EVENT_MGR_COMMUNICATE or /SAPTRX/BAPI_EH_ADDEVENTMSG_02 -> for Events
For performance, follow all the recommendations provided by all the members in this thread and additionally we can provide more inputs if you have any specific issues.
Thanks,
Vishnu