today I am going to show you how to root Xperia X8 2.1 directly!!!!

1. Download modified "SuperOneClick".
2. Enable "USB Debug".
3. Connect phone to "PC" and select "Charge Phone".
4. Open "SuperOneClick" and select "Root".
5. Wait!
6. When it is done, reboot.
NOTE:I am not responsible if this tutorial bricks your phone
             TRY this at your own risk 
if your mobile has superuser app with the android image as shown above ..
then your mobile has been rooted

download superoneclick.zip here
Referred from xda