[deploy] Add a script to merge two profiles, one with samples and one with markers

[mstange]

I've been using this script to make profiles of Firefox startup on Android, with sample data from simpleperf and marker data from the Gecko profiler.

I was using the following org.mozilla.fenix-geckoview-config.yaml:

env:
  PERF_SPEW_DIR: /storage/emulated/0/Android/data/org.mozilla.fenix/files
  IONPERF: func
  JIT_OPTION_emitInterpreterEntryTrampoline: true
  JIT_OPTION_enableICFramePointers: true
  JIT_OPTION_onlyInlineSelfHosted: true

  MOZ_PROFILER_STARTUP: 1
  MOZ_PROFILER_STARTUP_NO_BASE: 1 # bug 1955125
  MOZ_PROFILER_STARTUP_INTERVAL: 500
  MOZ_PROFILER_STARTUP_FEATURES: nostacksampling,nomarkerstacks,screenshots,ipcmessages,java,cpu,markersallthreads
  MOZ_PROFILER_STARTUP_FILTERS: GeckoMain,Compositor,Renderer,IPDL Background,*

[codecov[bot]]

Codecov Report

:x: Patch coverage is 0% with 111 lines in your changes missing coverage. Please review. :white_check_mark: Project coverage is 85.45%. Comparing base (d396f27) to head (a0ca052).

Files with missing lines	Patch %	Lines
src/merge-android-profiles/index.ts	0.00%	107 Missing :warning:
src/merge-android-profiles/webpack.config.js	0.00%	4 Missing :warning:

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5448      +/-   ##
==========================================
- Coverage   85.76%   85.45%   -0.31%     
==========================================
  Files         311      313       +2     
  Lines       30747    30858     +111     
  Branches     8455     8489      +34     
==========================================
  Hits        26370    26370              
- Misses       3953     4064     +111     
  Partials      424      424              

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[fqueze]

Is this specific to android? I could be tempted to merge a samply profile with a resource usage profile.

[mstange]

The part that's specific to Android / Linux is the use of startTimeAsClockMonotonicNanosecondsSinceBoot to align the timestamps in the two profiles.

Also, the markers from the "samples" profile are discarded. You are probably interested in keeping markers from both profiles, which will be more complicated because you'll also have to merge the schemas.

[fqueze]

You are probably interested in keeping markers from both profiles, which will be more complicated because you'll also have to merge the schemas.

If we added more useful markers to samply profiles, yes. Currently all the markers I see in these profiles are mmap markers that don't tell me much.