Consider removing project information by default

[rgrinberg]

Projectile information is quite useful, but the functions to get the project root can be quite slow. It would be great to have a mode to disable the projectile interaction.

In addition, the following field makes ivy-rich drastically slower:

      (ivy-rich-switch-buffer-project (:width 15 :face success))

While it's a useful field, it should not be in the default list of fields if it has such bad performance characteristics.

[Yevgnen]

Hi, how many project buffers are you using when you feel slow? Are you working with tramp?

I generally open about 300~500 buffers on my MacBook 2014 and don't feel any laggy though. The scrolling is still fluent enough in most (99.5% I think) cases.

(Note that the gif is missing frames and 'looks laggy'.)

Remote buffer parsing may be slow if you are having a slow tramp connection. But ivy-rich-parse-remote-buffer and ivy-rich-parse-remote-file-path may be set to nil to ignore remote buffers.

Also could you provide the detail result of profiling?

[rgrinberg]

Hi, almost all the buffers you have opened seem to belong to a project. This is indeed the fast path for projectile.

Hi, how many project buffers are you using when you feel slow?

I observe the slowness to be proportional to number of buffers without projects * how nested are the paths on the file system. When you have 50 such buffers open you will surely notice it. Go to /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include and open about 50 header files. You should observe the slowness.

Are you working with tramp?

I do not use tramp at all because it's too slow.

Also could you provide the detail result of profiling?

Sure, will do so.

[Yevgnen]

With the default value of projectile-project-root-files-functions, it's a very little bit slower with 150 of such buffers, but still quite fast. But anyway, the idea

Only when the file path of the buffer wasn't known it was necessary to get the projectile root.

should help to improve performance.

[rgrinberg]

I don't know to make a fancy gif, but here are my profiler results for a single call of ivy-switch-bufffer with around 50 buffers :)

For comparison, in my PR the cost projectile is barely registered by the profiler.

- command-execute                                                1219  96%
 - call-interactively                                            1219  96%
  - funcall-interactively                                        1219  96%
   - ivy-switch-buffer                                           1217  96%
    - ivy-read                                                   1217  96%
     - apply                                                     1217  96%
      - #<compiled 0x40507ccd>                                   1217  96%
       - read-from-minibuffer                                    1166  92%
        - ivy--queue-exhibit                                     1144  90%
         - ivy--exhibit                                          1144  90%
          - ivy--format                                          1144  90%
           - mapcar                                              1143  90%
            - ivy-rich--ivy-switch-buffer-transformer               1143  90%
             - ivy-rich-format                                   1143  90%
              - mapconcat                                        1143  90%
               - #<compiled 0x45fae891>                          1143  90%
                - ivy-rich-format-column                         1143  90%
                 - ivy-rich-switch-buffer-project                 888  70%
                  - ivy-rich-switch-buffer-in-project-p                888  70%
                   - projectile-project-name                      888  70%
                    - projectile-project-root                     888  70%
                     - cl-some                                    888  70%
                      - #<compiled 0x45f94691>                    888  70%
                       + projectile-root-top-down                 635  50%
                       + projectile-root-bottom-up                109   8%
                       + file-truename                             95   7%
                       + projectile-root-top-down-recurring                 48   3%
                 - ivy-rich-switch-buffer-path                    255  20%
                  - ivy-rich--switch-buffer-root-and-filename                255  20%
                   - ivy-rich-switch-buffer-in-project-p                255  20%
                    + projectile-project-name                     255  20%
        + #<compiled 0x404cde6d>                                   14   1%
        + minibuffer-inactive-mode                                  2   0%
        + timer-event-handler                                       2   0%
       + ivy--reset-state                                          25   1%
   + profiler-report                                                2   0%
+ timer-event-handler                                              42   3%
+ redisplay_internal (C function)                                   2   0%
+ global-font-lock-mode-check-buffers                               1   0%