Cloudsql CPU,Memory metrics are not being populated

When i installed and configured PMM2 for CLOUDSQL i am able to get the DB metrics but not o.s metrics of the cloudsql instance
How can we fetch them 
I searched for so many docs on this but not able to get the solution 

just a thought. may be you can incorporate this to your previous post, if possible. 
'How can we configure pmm client on Google cloudsql instances’

As of right now we only have the ability to “remote monitor” a Google Cloudsql instance (and only mysql or postgres instances, not their SQL server instance).  This connection is purely SQL based and thus only can read performance data with select or show queries.  It is on our roadmap to provide native integration with all 3 major cloud providers with full support for database and whatever instance metrics are available but system level metrics are currently unavailable on GCP or Azure.  

That question no one replied so i posted new question with better framing