Spacemacs is slow in moving cursor continuously in a big file

[ghost]

Hi,

I notice that when using the arrow keys to move the cursor continuously in a big file, such as .emacs.d/core/core-configuration-layer.el, the cursor movement often lags and is not smooth.

My guess is that during the cursor moving, there are some computations corresponding to the new cursor position, such as displaying eldoc, flycheck, flyspell... As the cursor continuously moves to a new position, these computations are performed again and again and this makes the cursor moving unsmooth.

Are there any ways to make the continuous cursor moving smooth?

If my guess is correct, is it possible to temporarily disable the events update during a continuous cursor moving?

Thanks for spending your time to look at my question!

[CeleritasCelery]

It is smooth for me. Sounds like you may need a performance upgrade for your computer.

[ghost]

Not really. My computer's CPU is Intel Core i7 6700, with 16GB of RAM.
This slowness can happen when Emacs load many modules.

[scriptmode]

You could profile emacs to figure out which functions eats up most performance. And then selectivly deactivate stuff or optimize their behaviour.

[CeleritasCelery]

Also keep in mind that Spacemacs can only optimize load time performance. The individual package owners control the preformace of their code. Therefore if a package or combination of packages are slowing you down, then there is not much Spacemacs can do. You can either disable packages or live with the preformace. @scriptmode's suggestion about profiling may be a good idea if you are looking for packages to disable. But you may just want to start with removing the packages and minor-modes you use the least.

[CeleritasCelery]

On another note, if you ever dealing with really large files (over 10,000 lines) you should consider vlf-mode

[ghost]

@scriptmode, @CeleritasCelery: Thanks for your suggestions. These sound really logical. I will monitor my Emacs's performance.

[ghost]

Hi, just a follow-up question.

I profiled the CPU usage and found out that the CPU consumption for redisplay_internal is quite high, especially the feature spacline-ml-tddsg, which is a customized version of spaceline. Is abnormal for the redisplay function?

In addition, the CPU usage of spaceline-ml-tddsg is 17%, but all its sub-items add up to only 6%. (2% + 1% + 1% + 1% + 1%). Where is the other 11%?

- redisplay_internal (C function)                                 420  21%
 - eval                                                           389  19%
  - spaceline-ml-tddsg                                            355  17%
   + powerline-raw                                                 46   2%
   + powerline-buffer-id                                           35   1%
   + mapcar                                                        29   1%
   + flycheck-has-current-errors-p                                 27   1%
   + run-hooks                                                     20   1%
   + powerline-wave-right                                          19   0%
   + powerline-wave-left                                           14   0%
     powerline-render                                              11   0%
     vc-state                                                       8   0%
   + powerline-width                                                7   0%
   + s-trim                                                         5   0%
   + powerline-hud                                                  4   0%
     eyebrowse--get                                                 4   0%
     file-remote-p                                                  4   0%
     get-frame-persp                                                2   0%
  + concat                                                         14   0%
    if                                                              4   0%
 + jit-lock-function                                               31   1%

[CeleritasCelery]

spaceline is notorious for causing problems with redisplay_internal (see #8462, #8060, #6120, #5063, #4730, or #4552). Some users have found that dotspacemacs-mode-line-unicode-symbols nil helps significantly. Others just disable the package all together. This seems to be a "works fine for some people, crashes everything for others" kind of problem.

[zeka0]

I encountered similar problem, but the file I was editing is small (less than 50 lines).
Spacemacs is slow when moving cursors using j or w, and what is odd is that,
when you press j multiple times, the cursor simply disappeared then reappeared at the expected position.
I was running Spacemacs on a virtual machine consisting of only 2G ram with 4 threads 2 core CPU.
Any ideas what might cause the problem and how to improve it?

[CeleritasCelery]

@zeka0 The problem is probably "running Spacemacs on a virtual machine consisting of only 2G ram with 4 threads 2 core CPU". You can take the advice mentioned above if you want to improve performance.

[armnrd]

Hi, just a follow-up question.

I profiled the CPU usage and found out that the CPU consumption for redisplay_internal is quite high, especially the feature spacline-ml-tddsg, which is a customized version of spaceline. Is abnormal for the redisplay function?

In addition, the CPU usage of spaceline-ml-tddsg is 17%, but all its sub-items add up to only 6%. (2% + 1% + 1% + 1% + 1%). Where is the other 11%?

- redisplay_internal (C function)                                 420  21%
 - eval                                                           389  19%
  - spaceline-ml-tddsg                                            355  17%
   + powerline-raw                                                 46   2%
   + powerline-buffer-id                                           35   1%
   + mapcar                                                        29   1%
   + flycheck-has-current-errors-p                                 27   1%
   + run-hooks                                                     20   1%
   + powerline-wave-right                                          19   0%
   + powerline-wave-left                                           14   0%
     powerline-render                                              11   0%
     vc-state                                                       8   0%
   + powerline-width                                                7   0%
   + s-trim                                                         5   0%
   + powerline-hud                                                  4   0%
     eyebrowse--get                                                 4   0%
     file-remote-p                                                  4   0%
     get-frame-persp                                                2   0%
  + concat                                                         14   0%
    if                                                              4   0%
 + jit-lock-function                                               31   1%

I am new to Emacs, and am not familiar with the profiler. Could you tell me how you did this?
My attempt:

M-x profiler-start
M-x profiler-stop
M-x profiler-report

This doesn't seem to do anything.

[duianto]

• profiler-start
• Choose cpu, mem or cpu+mem
• Perform the action you want to profile
• profiler-report opens the report buffer(s)
• profiler-stop when your done profiling.

https://www.gnu.org/software/emacs/manual/html_node/elisp/Profiling.html

[armnrd]

Thanks, that helps.

[elvinzeng]

• redisplay_internal (C function) 12618 76%
• evil-escape-pre-command-hook 2158 13%
• command-execute 703 4%
• timer-event-handler 466 2%
• ... 415 2%
• flycheck-handle-signal 66 0%
• flycheck-perform-deferred-syntax-check 6 0%
• which-key--hide-popup 3 0%
• evil--jump-hook 3 0%
  global-hl-line-unhighlight 3 0%

Mine is worse

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[darrenkenny]

I certainly experience a lot of lag when using either the spaceline or doom mode lines on MacOS - but only if running as a GUI, not if I use it in a terminal, in a terminal it flies along, but I lack the benefits then of the GUI mode.

In the reading that I've done this appears to be mainly down to the font rendering - suggestions that I've looked at has been to disable unicode characters and pick some specific fonts - some had minor benefits, but nothing reduced the lag as much as switching to the 'vanilla' mode line.

While not as pretty, it certainly helps for usability to avoid the lag.

[fab6]

Hi,
for me it is the same like @darrenkenny described. Using spacemacs development and emacs 27.1 on macos.

[lebensterben]

@darrenkenny
There is middle ground between terminal Emacs and full-GUI Emacs.
If you run an Emacs server in background daemon mode, then you are able to launch "terminal" Emacs in a GUI window. That is to say, you still have GUI only features like menubar, scroll bar, etc. But meanwhile, it's actually an terminal Emacs sessionl.

[fab6]

@lebensterben Could you elaborate on this a bit more; I understand that I could start a server with emacs-gui with server-start and open a file using emacsclient from the terminal with emacsclient file.
Is this what you meant?
Thank you!

[lebensterben]

@fab6
You can use systemd, for example, to register a service that starts emacs as a background daemon upon system starts.
Then, use "emacslient -a ''" to start the client. The additional option instructs it to start the server if it's not already on. You can create a new .desktop file with this command.

[fab6]

ok, thank you very much! I will check you I can get it to run with macos.. it seems that that the gui is not started from iterm, but the terminal emacs version.

[fab6]

and it looks actually here https://emacs.stackexchange.com/questions/18507/os-x-and-daemon-mode that this is not so easy to get the middle ground running on macos...

[lebensterben]

@fab6
it's just a one time set-up.

[fab6]

@lebensterben yes, that would not be the problem but I understood this part

that it might not even possible to get this running on macos without be plainly using gui... but maybe I misunderstood it

[lebensterben]

Best solution is to use Linux. bugOS is hard to use.

[fab6]

yes, that's right...

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This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Please let us know if this issue is still valid!