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bug#45248: 28.0.50; Emacs freezes with big C functions
From: |
Ravine Var |
Subject: |
bug#45248: 28.0.50; Emacs freezes with big C functions |
Date: |
Sat, 19 Dec 2020 09:58:48 +0530 |
User-agent: |
mu4e 1.5.7; emacs 28.0.50 |
Alan Mackenzie <acm@muc.de> writes:
> Let's be clear about the situation: CC Mode does just too much
> processing in refontification for current hardware to be able to scroll
> smoothly through a buffer at normal auto-repeat speeds. Setting
> fast-but-imprecise-scrolling to non-nil is a handy workaround, but it
> isn't good enough to make the scrolling appear to be smooth when one
> holds down C-v. I think (and hope) this is what you mean by
> "stuttering".
Yes, that's what I meant. These are my keyboard settings:
$ xset q | grep "repeat rate"
auto repeat delay: 200 repeat rate: 30
> The bug which I'm hoping to have fixed was that in the large struct in
> Wireshark's function proto_register_rrc, the scrolling got slower and
> slower as one got further into the struct. On my machine, 80% of the
> way through that struct, scrolling a single screen (62 lines) was taking
> between four and five seconds, which was unacceptably slow. With the
> bug fix, this scrolling takes about 75 milliseconds, regardless of the
> position in the struct. This is apart from the first screen drawing in
> the neighbourhood, which takes a little time to fill the new cache
> entry.
>
> Could you please confirm that you see the same uniformity in scrolling
> speed anywhere inside a large struct, and that the speed is acceptably
> close to instantaneous for a single scrolling operation. Or do you see
> something different? Thanks!
I still see the behavior that you have described. With the patch,
scrolling becomes slower and slower rapidly and the screen locks up
(using emacs -Q). I tested with a single C file containing just
the function proto_register_rrc().