bug#57207: 29.0.50; Fontification is slow after e7b5912b23 (Improvements to long lines handling)

[Ihor Radchenko]

Gregory Heytings <gregory@heytings.org> writes:

>> Do you have any idea what could be going wrong or how to debug things 
>> further?
>>
>
> Can you (a) provide a MRE so that we could track down what's going on 
> and/or (b) try to set long-line-threshold to a larger value (20000, 50000, 
> 100000) and see when the performance degradation disappears?

(a) It is hard. The problem appears when using a combination of a 20Mb
Org file and WIP Org mode branch.

(b) Setting long-line-threshold to nil makes the slowdown disappear.
Increasing long-line-threshold to 100000 made Emacs hang. I had to kill
it using kill -9.

-- 
Ihor Radchenko,
Org mode contributor,
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