@Swapan_Chhabra follow these steps!
- install command line appium
- start two instances of appium with different port e.g. 4723 and 4724
- create two java thread class with static variable port as 4723 and 4724 respectively with run method executing your appium script.
- Start both of the threads.(like wise you may use more threads.)
This is how very basic parallel execution you may achieve.
I achieved this by modifying appium source but it is totally self developed architecture similar to perfecto!