Hello,

I like to use ido mode for everything, including very large lists (like M-x
or info). Unfortunately ido is not suitable for such lists. On my old
notebook, performance is not amazing, so I took the challenge and spend
some time with profiler.

I improved the performance in several steps:

- inlined several functions
- disabled ido-case-fold for some completions (eg commands)
- prunning collections based on character bitmaps
- caching character bitmaps during completion or for same completions
- caching intermediate completion lists when adding new characters

You can view my changes on github:

- https://github.com/orfelyus/ido-speed-hack
- https://github.com/orfelyus/ido-mode-el

- (and optionally) https://github.com/orfelyus/ido-better-flex

ido-speed-hack includes large changes (bitmaps) while ido-mode-el includes
minor changes to ido.el

The changes made huge speed improvements on my notebook and ido does not
feel sluggish even with very large lists.

Could you please test my improvements? I would appreciate any feedback.
Dan

ps: I am not subscribed to the mailing list, please keep me in Cc