bug#69071: Emacs master branch: c-ts-mode is slow with large C functions.

[Yuan Fu]

> On Feb 15, 2024, at 12:36 AM, Eli Zaretskii <eliz@gnu.org> wrote:
> 
>> Date: Mon, 12 Feb 2024 11:30:00 +0000
>> From: Alan Mackenzie <acm@muc.de>
>> 
>> Using Emacs master:
>> 
>> c-ts-mode is slow on large C functions when editing towards the end of
>> such a function.
>> 
>> As an extreme example, there is a function proto_register_rrc in the
>> file packet-rrc.c which is part of Wireshark.  This file is "available"
>> from Github, but sadly no longer freely available - you need to allow
>> Microsoft's scripts to run on your machine.  I'm willing to send this
>> file by email to anybody who needs it.  It is almost 10 MB in size.
>> 
>> proto_register_rrc is around 50,000 lines long, total size about 2¼ MB.
>> 
>> Near the end of the function, after typing a character, there is a delay
>> of between 9 and 10 seconds (on my 7 year old machine) before redisplay
>> happens.  This is too long.  Some optimisation seems needed.
>> 
>> On disabling font-lock-mode, the response becomes instantaneous.
> 
> Yuan, could you please look into this?

Oops, didn’t see this. I’ll take a look.

Yuan