From: Andrey Orst <andreyorst@gmail.com>
To: Eli Zaretskii <eliz@gnu.org>
Cc: 46350@debbugs.gnu.org
Subject: bug#46350: 28.0.50; touchpad-scrolling-eats-lots-of-cpu-samples
Date: Sun, 7 Feb 2021 21:33:25 +0300 [thread overview]
Message-ID: <CAAKhXoYcXnhs0EwTVA8BCyC6aFmb9nOW-qD3JQnzaSxXCUs=YA@mail.gmail.com> (raw)
In-Reply-To: <83h7mnn4y6.fsf@gnu.org>
On Sun, Feb 7, 2021 at 8:49 PM Eli Zaretskii <eliz@gnu.org> wrote:
> 1350 calls during what time, approximately? less than a second?
If you've watched the video I've linked you can get a sense of what
time it takes -- about 15 seconds. Or more if I continue swyping
rapidly, since Emacs just sits at the bottom eating all input until I
stop.
Touchpad generates about 20-30 inputs per swipe, so I think ~90 inputs
is maximum human can produce in 1 second
> I don't think Emacs can scroll so fast, one line at a time. Note that
> when you scroll with the scroll-bar, Emacs doesn't call
> scroll-up/down, it just goes to a suitably calculated buffer position.
> Which is why scroll-bar scrolling is much faster. But I don't see how
> we can do something similar with the mouse-wheel, since it doesn't
> allow to calculate the buffer position to go to; Emacs needs to do
> that calculation itself, and that what makes the scrolling so much
> slower.
Can Emacs poll mouse events less frequently? Maybe some libinput stuff
needs tweaking?
> > > What is the size of the buffer that it scrolls almost instantly to
> > > BOB? How many lines?
> >
> > 1405 lines. I'm testing this on bundled lisp-mode.el
>
> Which explains why it scrolls in one go: 1405 ≅ 1350.
>
> So, once we've established that the touchpad injects 1-line scroll
> requests at such a high rate, what else needs to be investigated here?
There I was talking about progressive speed turned on, as it builds up
almost instantly with my touchpad producing 30 inputs per swipe.
--
Best regards,
Andrey Listopadov
next prev parent reply other threads:[~2021-02-07 18:33 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-06 17:33 bug#46350: 28.0.50; touchpad-scrolling-eats-lots-of-cpu-samples Andrey Orst
2021-02-06 17:59 ` Eli Zaretskii
2021-02-06 18:34 ` Andrey Orst
2021-02-06 18:55 ` Andrey Orst
2021-02-06 19:05 ` Eli Zaretskii
2021-02-06 19:02 ` Eli Zaretskii
2021-02-06 19:47 ` Andrey Orst
2021-02-06 20:03 ` Eli Zaretskii
2021-02-07 17:23 ` Andrey Orst
2021-02-07 17:49 ` Eli Zaretskii
2021-02-07 18:33 ` Andrey Orst [this message]
2021-02-07 18:44 ` Eli Zaretskii
2021-02-07 18:52 ` Andrey Orst
2021-02-07 19:05 ` Eli Zaretskii
2021-02-07 19:37 ` Lars Ingebrigtsen
2021-02-07 19:47 ` Eli Zaretskii
2021-02-07 20:54 ` Lars Ingebrigtsen
2021-02-07 22:16 ` Alan Third
2021-02-07 22:22 ` Andrey Orst
2021-02-07 22:24 ` Alan Third
2021-02-07 22:30 ` Andrey Orst
2021-02-08 10:12 ` Andrey Orst
2021-02-08 14:35 ` Andrey Orst
2021-02-08 15:28 ` Eli Zaretskii
2021-02-08 15:31 ` Andrey Orst
2021-02-08 15:19 ` Eli Zaretskii
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