Re: macOS metal rendering engine in mac port

[Eli Zaretskii]

> From: Dmitry Gutov <dgutov@yandex.ru>
> Date: Sat, 29 May 2021 21:00:42 +0300
> Cc: alan@idiocy.org, emacs-devel@gnu.org
> 
> On 29.05.2021 20:43, Eli Zaretskii wrote:
> > So it's a difference of 10ms, and you are able to feel such a small
> > difference?  AFAIK, it's way below the threshold of human's ability to
> > perceive time intervals.  Anything below 100ms is intangible.
> 
> That's not quite true: 100ms might be the limit of human reaction to 
> unanticipated events

No, not "reaction", "perception".  (Reaction to unanticipated events
is much slower, 1 to 2 sec.  Reaction to anticipated events can be
around 250ms.  But we are not talking about reaction, because
perceiving a delay doesn't require any reaction.)

This:

  https://www.britannica.com/science/time-perception/Perceived-duration

says 0.1 sec of visual experience is needed to perceive time duration.
And there are other similar sources.  It is also consistent with my
own experience, from the time when I measure performance of
bidirectional display and compared it with my subjective notion of
"delay": anything below 100ms was barely tangible, anything below 50ms
was perceived as "instantaneous".