Applying for the TRP at the Canadian visa office may take up to six (6) months to process. The processing time depends on the visa office you are applying to. There are certain locations that are busier than the others.
The time may also depend on the type of admissibility you may have. For instance, convictions on your criminal record may be more complicated or serious and the decision on those applications may take more time. Depending on the case you may be called for an interview, although they are rare.