perf(1) map not working with --perf-basic-prof-only-functions

[lukealbao]

Hi!

We've been running our production workloads with the --perf-basic-prof-only-functions flag and recording profiles with perf(1) with great success on node 14. Recently we upgraded to v16 and all the JIT symbols have been lost.

I ran two instances of the same code on node 16.

With --perf-basic-prof:

head /tmp/perf-1.map
1561c20 53c Builtin:RecordWriteEmitRememberedSetSaveFP
1562160 1c4 Builtin:RecordWriteOmitRememberedSetSaveFP
1562340 26c Builtin:RecordWriteEmitRememberedSetIgnoreFP
15625c0 d0 Builtin:RecordWriteOmitRememberedSetIgnoreFP
15626a0 160 Builtin:EphemeronKeyBarrierSaveFP
1562820 74 Builtin:EphemeronKeyBarrierIgnoreFP
15628a0 3c Builtin:AdaptorWithBuiltinExitFrame
15628e0 148 Builtin:CallFunction_ReceiverIsNullOrUndefined
1562a40 180 Builtin:CallFunction_ReceiverIsNotNullOrUndefined
1562be0 19c Builtin:CallFunction_ReceiverIsAny

With --perf-basic-prof-only-functions:

head /tmp/perf-1.map
7feddb4ccb00 8f8 RegExp:\/[*/]#\s+sourceMappingURL=(?<sourceMappingURL>[^\s]+)
7feddb4cd460 5f4 RegExp:(?:^|\/)\.?\.$
7feddb4cf9c0 5dc RegExp:\/[*/]#\s+sourceMappingURL=(?<sourceMappingURL>[^\s]+)
7feddb4d0000 768 RegExp:^((?:@[^/\\%]+\/)?[^./\\%][^/\\%]*)(\/.*)?$
7feddb4d27e0 a8a4 RegExp:(^|\\|\/)((\.|%2e)(\.|%2e)?|(n|%6e|%4e)(o|%6f|%4f)(d|%64|%44)(e|%65|%45)(_|%5f)(m|%6d|%4d)(o|%6f|%4f)(d|%64|%44)(u|%75|%55)(l|%6c|%4c)(e|%65|%45)(s|%73|%53))(\\|\/|$)
7feddb4dd100 3c0 RegExp:%2F|%5C
7feddb4e9160 25c RegExp:^\uFEFF
7feddb4f4520 360 RegExp:[\\^$.*+?()[\]{}|]
7feddb4f48e0 68c RegExp:hasOwnProperty|(function).*?(?=\\\()| for .+?(?=\\\])
7feddb4f4fe0 4a4 RegExp:^function.*?\(\) \{ \[native code\] \}$

#407 (comment) notes that support for perf is traditionally unofficial but does work (up to v14, as of that comment). Was support officially or effectively abandoned in v16? Thanks!

[RafaelGSS]

See nodejs/node#50079

[lukealbao]

I'll pick this up over at node#50225