delete table space

Hi All,
Kindly advice for the below issue,

i have table it’s size more than 1TB and i try to drop it but it didn’t free space in file system.
what i should do if i need to freeup this table space ??

i have Percona-Server-5.6.21-70.1-r698-el6-x86_64

If the innodb_file_per_table is off that is normal please see.

https://www.percona.com/blog/2014/08/21/the-mysql-ibdata1-disk-space-issue-and-big-tables-part-1/

https://www.percona.com/blog/2013/09/25/how-to-reclaim-space-in-innodb-when-innodb_file_per_table-is-on/