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. This is unused on MS-Windows when w32image-create-thumbnail is used instead of ImageMagick or GraphicsMagick commands. In addition, even if those commands are available, the actual number of concurrent jobs will be limited by 30 from above, since Emacs on MS-Windows cannot have too many concurrent sub-processes.

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.
This is unused on MS-Windows when `w32image-create-thumbnail' is
used instead of ImageMagick or GraphicsMagick commands.
In addition, even if those commands are available, the actual number
of concurrent jobs will be limited by 30 from above, since Emacs
on MS-Windows cannot have too many concurrent sub-processes.")