bug#2530: 23/NS: redraws according to mouse-face are slow

[Christian Kruse <cjk@defunct.ch>]

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Hi,

Andrew Hyatt <ahyatt@gmail.com> writes:

> There's a bunch of discussion before, in 2009, but as of now, for Emacs
> 25, I don't notice any particular slowness on El Capitan.  Can anyone
> still reproduce a problem here?

Compared to Linux (the Linux hardware is slower, a Notebook from 2011
and the OS X notebook is a Macbook Pro Retina from 2014), the OS X
version is *pretty* slow. While everything I do with Emacs is nearly
instant when using Linux there is a notably delay when using Emacs with
OS X. The worst example is Magit, which I already profiled because it is
*so* slow: when using Linux `magit-status` shows up instantly. It takes
about 1.5 seconds when using OS X (hold it, I am aware that this is not
the place to discuss Magit performance, it is just an example :-) Every
buffer with lots of lines (e.g. a notmuch buffer with 26k mails, my
archive of the pg-hackers list) is lightning fast when using Linux, but
takes round about 30 seconds when using OS X.

Although I’m not sure that it is only the rendering engine (of course it
could also be the elisp interpreter being slower) it occurs to me that
it plays its part: especially redraw actions seem to be very slow. For
example mu4e is unbearable slow when displaying maildirs with a lot of
mails (e.g. the 26k mails maildir I mentioned above) but works fine for
small mailboxes; and while the content of the maildir is loading, the
buffer is flickering all the time as if it gets redrawn all the time.

Best regards,
-- 
Christian Kruse
https://wwwtech.de/about

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