memory_profiler reporting itself

[ohaddahan]

I noticed today (I also updated my Gems today , so it might be related). That memory_profiler now reports it's own footprint as a part of the analysis report. I believe this wasn't the case before and it creates a false top level analysis metrics.

See the example here: https://gist.github.com/ohaddahan/cdaef533abf963f16f7bccec141c2185

Most of the memory report is actually caused by memory_profiler.

Total allocated: 28693134 bytes (206218 objects)
Total retained:  28671354 bytes (205866 objects)

allocated memory by gem
-----------------------------------
  28664857  memory_profiler-0.9.8
     26437  chili-hunter-2/app
      1840  activesupport-5.0.0

[dgynn]

I think you may have mixed the .start/.stop mode with the .report mode in your IRB session.

I can recreate memory_profiler self-reporting by calling MemoryProfiler.start first. I expect that your IRB session got into a weird state this way.

MemoryProfiler.start
MemoryProfiler.report { "allocate one string" }.pretty_print

Total allocated: 1496 bytes (10 objects)
Total retained:  232 bytes (1 objects)

allocated memory by gem
-----------------------------------
      1456  memory_profiler/lib
        40  other
...

Please re-open this issue if can recreate the problem in a clean IRB session or a script.

[seanlinsley]

BTW @dgynn unless GitHub has changed how it works, issue creators can't re-open issues that a contributor has closed.

[dgynn]

Thanks @seanlinsley I didn't realize that.

[ohaddahan]

@dgynn it's a 100% not due to me calling MemoryProfiler.start since I never use that and always opt for :

report = MemoryProfiler.report do
......
  end 
  report.pretty_print( to_file: 'file.txt' )

But it's a little spurious , I'll try creating a more consistent testcase.

[dgynn]

@ohaddahan Oh, here's a possible cause. If the block of code being reported on throws an exception we are not cleaning up correctly.

MemoryProfiler.report { raise "error" } rescue nil
MemoryProfiler.report { "allocate one string" }.pretty_print

Total allocated: 1496 bytes (10 objects)
Total retained:  232 bytes (1 objects)

allocated memory by gem
-----------------------------------
      1456  memory_profiler/lib
        40  other

Is it possible that happened in your IRB session? That is something we should handle better.

[ohaddahan]

@dgynn might be it , I'll give a try. Sounds possible since ctrl+C is quite common during interactive debug session :)