Working with tempdb

DBCC FREEPROCCACHE

GO
DBCC DROPCLEANBUFFERS
go
DBCC FREESYSTEMCACHE ('ALL')
GO
DBCC FREESESSIONCACHE
GO

select * from sys.dm_db_file_space_usage

select * from sys.dm_db_session_space_usage

select* from sys.dm_db_task_space_usage