Re: Timings for 'make check' with and without symbols with position

[Eli Zaretskii]

> Date: Sun, 27 Feb 2022 12:15:14 +0000
> From: Alan Mackenzie <acm@muc.de>
> Cc: ofv@wanadoo.es, deng@randomsample.de, mattiase@acm.org, 
> emacs-devel@gnu.org,
>  gregory@heytings.org, larsi@gnus.org
> 
> Char-tables seem to have something to do with it.  The perf output for
> mark_char_table increase from 2.98% to 3.79%.  Adding the 12.6% factor
> onto the 3.79% gives us 4.27%.  That's a factor of ~1.5 increase.
> 
> I'm still slogging through the detailed output for mark_char_table,
> which is not easy in the optimised build.  I suspect that somehow,
> somewhere, symbols with position have got themselves into a char-table,
> and they take (a lot) longer to process than bare symbols (for which
> mark_char_table is optimised).  I've not yet managed to find such a
> char-table though.

We do have a few char-tables whose slots are symbols or include
symbols.  unicode-category-table is one, for example;
composition-function-table is another.

Thanks for working on this.