Hello Rakesh,
Can you give some more information about what you are trying to test? Are you talking about bandwidth utilization over LAN? It would help to know what kind of performance metrics you want to get.
Two that come to mind from the Esri Enterprise Implementation team are:
- Mxdperfstat: A command-line tool that will draw your map at different scales and report the refresh time (draw speed), number of features returned, number of vertices, and the amount of time consumed at each phase of the performance chain (graphics, cursor, DBMS, etc). It'll even flag layer/scale combos that draw at sub-optimal performance and provide recommendations to get them drawing faster.
- System Test for the Web: This is more for testing server products (map services, feature services, etc) but you can apply various user loads and generate reports on the relative performance (wait time, failed requests, etc) over the duration of the test.
Besides that, there's Geocortex Analytics which I haven't used but looks cool and might help.
Good luck!
Micah