You have a couple of choices:
1. Contact IRCC via email or CSE. Will most likely you will receive a reply that security screening is in process.
2. If you are within the 6 months processing time limit, do not worry, just wait it out.
3. You can consider ordering GCMS to know if there were any issues with your eligibility, or has there been a document request sent to a partner country which IRCC is waiting for. Also, on some occasions the security is processed, but the file is not updated, so the GCMS notes will help you as before they are released, and officer has to review them and will update the file.
4. Contact CSIS and find if they have completed processing. Procedure available
https://goo.gl/7wQ5CT
Apart from these, you will have to wait it out.