Hi Sudhakar,
Please find the steps to check run time of all your BW queries in detailed.
1. Logon to RRMX and execute your query or through RSRT.
2. logon to T code - ST03N.
3. Change your view mode from Administrator to Expert mode.
4. Select the BW system load and drill down.
5. Double Click on today.
6. On Right hand side, you can click on share of your runtime tab or any.
7. Now you can view run time by choosing aggregation level either on Info cube or Query along with No - OLAP cache or OLAP Cache.
8. You can further go in detail for any other information.