Support for capturing heap and tracing-API-based profiles

[connor4312]

Right now we can capture CPU profiles. We should also support heap profiles for all targets, and can consider supporting tracing API-based profiling for browsers.

[jasonwilliams]

This is exciting.
I suppose there needs to be an option to start and stop right?
So we can pick and choose which bits we want to capture

[connor4312]

This issue is a good one for Grace Hopper / Hacktoberfest!

Collecting a heap profile here should be possible with plug-ins to our existing functionality. The "Chrome Debug Protocol" is how we talk to the debuggee (Node.js, or browsers). CDP docs for heap profiling here -- you'll probably want to look at the sampling heap profile initially.

You want to create a new IProfiler class here and bind it in the IOC container. The interfaces should guide you through what's needed. You'll probably want to abstract and reuse some of the location-massaging code from the CpuProfiler.

Once it's there, the "Start Profiling" command (available when running a Node.js program) will open a picker asking you what kind of profile you want to take.

Additional extra things you could do once you have that working:

• Currently, profiling is duration based, but users could also want to take point-in-time snapshots of their heap. You can add support for this, which will involve some changes in the ui side of things since there's no 'termination condition'
• You can add support for viewing the resulting heap profile files to the visualizer: https://github.com/microsoft/vscode-js-profile-visualizer

General contributing/setup: https://github.com/microsoft/vscode-js-debug/blob/master/CONTRIBUTING.md#development

[timjensen-kr]

@connor4312 Any idea when this might get added? We would love to use this functionality

[connor4312]

We had a contribution to add heap profiling. Currently no plans to add a tracing profiler to VS Code. This is not supported by V8/Node.js anyway.