Comment by felixge

First of all, I think the .eh_frame unwinding y'all pioneered is great.

But I think you're only thinking about CPU profiling at <= 100 Hz / core. However, Brendan's article is also talking about Off-CPU profiling, and as far as I can tell, all known techniques (scheduler tracing, wall clock sampling) require stack unwinding to occur 1-3 orders of magnitude more often than for CPU profiling.

For those use cases, I don't think .eh_frame unwinding will be good enough, at least not for continuous profiling. E.g. see [1][2] for an example of how frame pointer unwinding allowed the Go runtime to lower execution tracing overhead from 10-20% to 1-2%, even so it was already using a relatively fast lookup table approach.

[1] https://go.dev/blog/execution-traces-2024

[2] https://blog.felixge.de/reducing-gos-execution-tracer-overhe...