CPU/memory profiler

[bioball]

To help debug performance issues, there should be a way to profile CPU/memory usage when running a Pkl program.

[RushikeshGandhmal]

Hi @bioball,

I would be interested in working on this. I took a first pass through the current evaluator and Truffle setup, and it looks like we could build on the existing GraalVM profiler tooling: CPUSampler for CPU profiles, and Truffle allocation instrumentation for memory profiles.

Before I start, could you clarify the intended scope for the first version?

• Should profiling cover eval, run, and test, or only a particular command?
• Does it need to work in both the native pkl executable and jpkl?
• For memory profiling, are you looking for allocations attributed to Pkl code, overall heap/process usage, or both?
• Is there a preferred output format, such as a terminal histogram, JSON, or a flame graph?

The CPU side appears relatively direct. Memory attribution would also require Pkl to report guest-language allocations through Truffle, so I want to make sure I understand the expected result before changing that part of the runtime.

Thanks — I am happy to put together an implementation once the intended interface is clear.

[bioball]

H @RushikeshGandhmal, thanks for your interest, but we aren't looking for a contribution for this one.

[RushikeshGandhmal]

Okay @bioball, thanks for confirmation!