runtime/pprof: mechanism to show runtime frames in heap profiles

[prattmic]

runtime/pprof hides "runtime" frames in heap profiles, so allocations in maps appear at the map assignment location in the calling code, but not in runtime.mapassign itself.

Personally I find this behavior frustrating because it makes it much more difficult to look at the overall impact of maps in general on the heap, since there is no common frame to look at. I think it would be nice to have a mechanism to keep runtime frames in heap profiles. Perhaps something like GODEBUG=heapprofileruntimeframes=1.

I broke the runtime frame hiding in 1.24 (#71174) and discovered the bug because @bboreham mentioned that they liked the change!

[gabyhelp]

Related Issues

• runtime/pprof: map allocation runtime frames no longer hidden in 1.24 #71174
• runtime: frames for functions called via reflection are not shown in heap profiles #18077 (closed)
• runtime/pprof: inline frames may not use combined location #37446 (closed)
• proposal: runtime/pprof: cross system stack transitions in the heap profiler #66385

Related Code Changes

• runtime/pprof: write heap statistics to heap profile always
• cmd/pprof: add -runtime flag

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