Review performance testing

[ajgdls]

Hello, I've written a small Python module https://github.com/ajgdls/EPICSPyClientPerformance to compare the performance of 6 Python based EPICS clients. I have attempted to test each in a consistent way, and the README has some preliminary results for monitoring 1000 records at 10Hz for 1000 samples.

I would really appreciate it if this module owner would review EPICSPyClientPerformance test code for this client implementation to check that I'm actually testing in the correct and most efficient way. I would be happy to make updates that shows an increase in performance for this client.

This testing is driven by Diamond Light Source, and on 1st December the tests will be re-run against latest PyPI versions and then published (probably tech-talk) for further discussion, so if anyone wants to push performance optimisations they will get picked up on that date.

Thanks for taking a look, looking forward to hearing from everyone.

[mdavidsaver]

on 1st December the tests will be re-run against latest PyPI versions and then published

@ajgdls Are you willing to run your tests before this "final exam"? I have some changes (#90) to both P4P and the PVXS library which I would like to see results for prior to merging. Your feedback would help me decide if the API additions are worthwhile.

I've arranged things so that both PRs can be built locally via pip. I suggest a clean virtualenv, or explicit uninstall of any pypi.org builds. The build machine should only need python and a supported c++ compiler (eg. gcc >= 4.8 circa RHEL7)

pip install -v --no-binary epicscorelibs,pvxs,p4p git+https://github.com/mdavidsaver/p4p@net-opt

[ajgdls]

Hi @mdavidsaver of course! And it isn't an exam :) , we decided to put a date to hopefully encourage participation but not really to give hard deadlines. I'm more than happy for people to re-run or improve the tests anytime against any future versions if they see a benefit.
I should be able to run your tests today and I'll feed back to you.

[coretl]

I had a quick go with your updates and it improves by about 10%. I tried a bit of profiling with py-spy top and got:

# py-spy top -- python -m EPICSPyClientPerformance -c p4p -r 1000


Collecting samples from 'python -m EPICSPyClientPerformance -c p4p -r 1000' (python v3.8.15)
Total Samples 2700
GIL: 1.00%, Active: 14.00%, Threads: 5

  %Own   %Total  OwnTime  TotalTime  Function (filename)                                                                                                                                      
  1.00%   1.00%    1.10s     1.46s   pop (p4p/client/raw.py)
  2.00%   2.00%   0.740s    0.750s   cpu_percent (psutil/__init__.py)
  0.00%   0.00%   0.440s    0.470s   notify (threading.py)
  0.00%   0.00%   0.280s    0.280s   __str__ (p4p/nt/scalar.py)
  0.00%   1.00%   0.230s    0.560s   add_sample (EPICSPyClientPerformance/monitor_client.py)
  0.00%   0.00%   0.170s    0.170s   _store (p4p/nt/scalar.py)
  0.00%   2.00%   0.100s     2.39s   handle (p4p/util.py)
  0.00%   0.00%   0.090s    0.260s   unwrap (p4p/nt/scalar.py)
  0.00%   0.00%   0.080s    0.760s   _event (p4p/client/thread.py)
  0.00%   0.00%   0.080s    0.610s   put (queue.py)
  0.00%   0.00%   0.080s    0.340s   unwrap (p4p/nt/__init__.py)
  0.00%   0.00%   0.080s    0.150s   get (queue.py)
  0.00%   0.00%   0.070s    0.070s   isEnabledFor (logging/__init__.py)
  1.00%   1.00%   0.060s    0.130s   debug (logging/__init__.py)

cpu_percent can be ignored as it is in another thread, but the rest is what is being profiled.

[ajgdls]

Hi @mdavidsaver I ran the tests with your PRs installed into a clean virtual environment and got the following

2022-11-04 14:03:08,604 CPU: Mean 66.69055118110224
2022-11-04 14:06:06,354 CPU: Mean 68.33109243697467
2022-11-04 14:13:56,462 CPU: Mean 68.03557692307683

I ran a few times to ensure the results were consistent