Slow straight bootstrap

[haji-ali]

How long is bootstrapping straight expected to take?
Right now it is taking an average of 1.7 seconds on my machine (compared to the rest of my config which takes less than 0.5 seconds). I benchmarked bootstrap.el and it seems that executing these lines

https://github.com/raxod502/straight.el/blob/e1390a933b6f5a15079d6dec91eac97a17aad10c/bootstrap.el#L82-L84

Takes an average of 1.6 seconds.

Is this expected? If so, is there a way to speed this up?

[progfolio]

Does the bootstrap process take that long when using straight-bug-report?

[haji-ali]

No, it seems to run much faster. Running

(straight-bug-report
  :pre-bootstrap
  (setq my//bootstrap-start (current-time))
  :post-bootstrap
  (message "Bootstrapping done in %.03fs"
           (float-time (time-subtract (current-time) my//bootstrap-start)))
  :user-dir "/tmp/straight.el-test"
  :preserve t)

the second time takes 0.1 to 0.2 seconds.

This might be a bug in Radian then. Is there a more verbose mode of straight that I can enable to get diagnostics of what straight is doing?

[progfolio]

Is there a more verbose mode of straight that I can enable to get diagnostics of what straight is doing?

In this situation I would recommend using Emac's elisp profiler:

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

You could advise straight-use-recipes and conditionally start/stop the profiler when
the package is melpa. Try adding something like this prior to straight's bootstrap code (I'm not familiar enough with Radian to say exactly where):

(defun +straight-profile-use-recipes (advised recipe)
  (let ((melpa (eq (car recipe) 'melpa)))
    (when melpa (profiler-start 'cpu+mem))
    (prog1
        (funcall advised recipe)
      (when melpa (profiler-stop)))))

(advice-add #'straight-use-recipes :around #'+straight-profile-use-recipes)

This will add the advice and start the profiler when the melpa recipe is passed to straight-use-recipes.

Then after init, you can M-x profiler-report. This will pop open the profiler buffer. You should be able to see where most of the CPU time is being spent there by drilling down through the report. If nothing looks amiss, you may have to move the call to profiler-start sooner. In that case I would ditch the advice and just insert the calls into your init file.

Does that help?

[haji-ali]

Thank you! This is a really nice way to profile.

I found out that the reason is that straight--cache-package-modifications is being called at start-up which is really slow.
This is because straight-check-for-modifications has find-at-startup by default and I have many files in my straight repo directory. Removing this flag improved my Emacs startup time considerably.

[raxod502]

Right, see https://github.com/raxod502/straight.el/tree/e1390a933b6f5a15079d6dec91eac97a17aad10c#summary-of-options-for-package-modification-detection. There are tradeoffs between startup time, reliability of modification detection, and number of system dependencies for the different strategies for modification detection.

See also #694 (comment), in @progfolio came up with an idea that might be able to get all the advantages without any real downsides.