Install an Application Performance Monitoring (APM) tool in both locations, and configure an export to a central data storage location for analysis.

Instrument the code using a timing library, and publish the metrics via a health check endpoint that is scraped by Cloud Monitoring.

Import the Cloud Debugger package, and configure the application to emit debug messages with timing information.

Import the Cloud Profiler package, and configure it to relay function timing data to Cloud Operations for further analysis.