sql server print time with milliseconds

print convert(varchar, getdate(), 121)

declare @callID as int
declare @errCode as int
declare @msg as nvarchar(200)

exec [sp_Test_alwayRetTrue] @callID,@errCode out,@msg out

print @msg
print convert(varchar, getdate(), 121)

output   : 

2017-04-07 09:12:22.707
success to create ongoingcall
2017-04-07 09:12:25.710