Question: Performance Issues because of syntax checks

[buhtz]

Performance problems while typing

I am sorry for using the Issue section but the REAMDE.md tells me so and I was not able to find another contact the the "user community". This is not a bug or a feature. Just a problem of a not so well informed and unexperienced emacs and elpy user.

The problem is that emacs (GUI & terminal) becomes quite slow while typing Python code. It looks like that it has to do with on-the-fly syntax checking. But I am not sure.

I can swich of flymake-mode but then I also lose every syntax checks. I need my syntax check minimum when saving a file or better when moving to a new row. But not on every char I type. I like and need the red ! on the line number column and the red underlines.

When I open a comment string with """ of course the rest of the python source file becomes a comment in that moment and that confuses the syntax checker. This is just one of the examples.

Problem with reference docu in minibuffer

Another problem is that I got shown the reference docu (e.g. from pandas.read_csv()) when I enter the relevant row in the code. The docu is shown in a minibuffer. I do not need this. Can be switched of to improve performance.

Solutions

I am sure a lot of things can be modified on elpy. What can I do to modify this?

More details

My current init.el. Or should I post it directly here?

I installed elpy via one of the tutorials on the web. I am using GNU Emacs 26.1 (build 2, x86_64-pc-linux-gnu, GTK+ Version 3.24.5) of 2021-01-31, modified by Debian and elpy from melpa. Sorry I am even not able to tell you my elpy version. I do not know where to get it form.

I am not sure what else is working together or under elpy.

[galaunay]

On flymake performance

If flymake is really the cause of the slow down, you can delay it execution with :

(setq flymake-no-changes-timeout 5)

Else, you can try profiling to identify what really cause the slowdown (take a look at profiler-start and profiler-report functions).

On reference in minibuffer

That comes from eldoc, so you can deactivate this minor mode to remove it completely. If what bothers you is the fact that it takes a lot of lines, you can play with eldoc-echo-area-use-multiline-p and other eldoc customisation variables.

I hope it helps.

[buhtz]

Booth tips are very helpful. I can definitly say that the performance problem was because of flyemake.

[buhtz]

I isolated a similar problem when typing docstrings.
Detailes and a solution can be found here https://emacs.stackexchange.com/a/63852/12999

[buhtz]

Because the subject fit very well I re-opened here instead of creating a new Issue.

Just to summarize the past. We found 3 reasons for performance problems and their solutions which helped a lot. For the special 3 situations there are no performance problems anymore. But I still have performance problems and I thing they are elpy-related or related to one of the underlying components. I monitor my CPU cores (4 logical) in my taskbar ("panel" in linux speech?).

I am not sure what cause it but from time to time when editing a python file one core goes to 100% and emacs freezes for 2-4 seconds.

Just about the machine. It is a Intel(R) Core(TM) i3-4130T CPU @ 2.90GHz with 8 GB RAM. Not much but it should be enough to edit text files and using emacs.

I tried out profiler-report and found this. Any idea about it? There is something with flymake and the line-number-at-pos.

- #<compiled 0x1611155>                                         28846  90%
 - python--flymake-parse-output                                 28845  90%
  - flymake-diag-region                                         20345  63%
     line-number-at-pos                                         19601  61%
   - end-of-thing                                                 744   2%
    - bounds-of-thing-at-point                                    740   2%
     - thing-at-point--end-of-sexp                                704   2%
      + forward-sexp                                              704   2%
     - thing-at-point--beginning-of-sexp                           36   0%
        syntax-ppss                                                28   0%
        forward-sexp                                                4   0%
  + #<compiled 0x1610d55>                                          36   0%
    assoc-default                                                  32   0%
- linum-update-current                                           1670   5%
 + linum-update                                                  1670   5%
+ command-execute                                                1181   3%
+ ...                                                              82   0%
+ yas--post-command-handler                                        48   0%
+ redisplay_internal (C function)                                  42   0%
+ timer-event-handler                                              29   0%
+ elpy-rpc--filter                                                 12   0%
+ evil--jump-hook                                                   4   0%
+ undo-auto--add-boundary                                           2   0%

I am not sure if I used the profiler correct. There is no life report buffer right?

EDIT:
I checked the version of related components and did some updates.

• updated emacs itself from 1.26.1 to 1.27.1 (debian-backports-repo).
• Emacs package flymake updated to 1.1.1 (gnu)
• elpy is 1.28.0