(slow) operations tracker

[joaquimg]

This adds the optional ability to mark all places where slow operations that allocate expression occur. Keeping the stack might be a lot of data, but it is a way to properly identify the issues instead of erroring one by one.

Possible additional functionality:
1 - also mark the operation type. A bit redundant with the stack, but might lead to summary reports.
2 - create a user friendly summary

TODO

• add tests
• add docs session, to be referenced in the performance issues.

[codecov]

Codecov Report

Attention: Patch coverage is 65.41353% with 46 lines in your changes missing coverage. Please review.

Project coverage is 99.25%. Comparing base (57132d8) to head (bd416ee).

Files with missing lines	Patch %	Lines
src/operators.jl	65.41%	46 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##            master    #3970      +/-   ##
===========================================
- Coverage   100.00%   99.25%   -0.75%     
===========================================
  Files           43       43              
  Lines         6076     6207     +131     
===========================================
+ Hits          6076     6161      +85     
- Misses           0       46      +46     

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[odow]

I think we decided not to do this.

We have some better support with set_macro_timing , but this tutorial could still be improved:

https://jump.dev/JuMP.jl/dev/tutorials/getting_started/debugging/#Debugging-performance-problems

[joaquimg]

I am not sure we should close yet.
I still think macros and this are very different things.
I am thinking about counting allocations here, it might be useful to rank operation types.

[odow]

I don't know what the right approach is, but after thinking about this more I don't think that it's this PR.