Variable: image-dired-queue-active-limit
image-dired-queue-active-limit is a variable defined in
image-dired-external.el.gz.
Value
4
Documentation
Maximum number of concurrent jobs permitted for generating images.
Increase at your own risk. If you want to experiment with this,
consider setting image-dired-debug(var)/image-dired-debug(fun) to a non-nil value to see
the time spent on generating thumbnails. Run clear-image-cache
and remove the cached thumbnail files between each trial run.
Probably introduced at or before Emacs version 26.1.
Source Code
;; Defined in /usr/src/emacs/lisp/image/image-dired-external.el.gz
(defvar image-dired-queue-active-limit (min 4 (max 2 (/ (num-processors) 2)))
"Maximum number of concurrent jobs permitted for generating images.
Increase at your own risk. If you want to experiment with this,
consider setting `image-dired-debug' to a non-nil value to see
the time spent on generating thumbnails. Run `clear-image-cache'
and remove the cached thumbnail files between each trial run.")