From: Eli Zaretskii <eliz@gnu.org>
To: Stefan Monnier <monnier@IRO.UMontreal.CA>
Cc: sva-news@mygooglest.com, 15876@debbugs.gnu.org, dmantipov@yandex.ru
Subject: bug#15876: 24.3.50; Highly degraded performance between rev 114715 and 115006
Date: Fri, 13 Dec 2013 20:53:24 +0200 [thread overview]
Message-ID: <83txec4m6z.fsf@gnu.org> (raw)
In-Reply-To: <jwveh5g3dnv.fsf-monnier+emacsbugs@gnu.org>
> From: Stefan Monnier <monnier@IRO.UMontreal.CA>
> Cc: Eli Zaretskii <eliz@gnu.org>,
> Jan Djärv
> <jan.h.d@swipnet.se>,
> sva-news@mygooglest.com, 15876@debbugs.gnu.org
> Date: Fri, 13 Dec 2013 11:45:15 -0500
>
> > aren't typical use cases, holding ~200M which we can't reuse is worth
> > trying to fix, IMHO.
>
> Actually, we *can* reuse that memory, but only by selecting those
> fonts again. I agree with Eli: the benefit is very small.
The problem is not with fonts, it is with font-entities stored in a
font cache. For some reason that I cannot understand, Emacs needs to
consult the font cache when it looks for a font suitable for
displaying a character, even when the character was already displayed,
and the face (including the font) used for its display was already
realized and cached in the frame's face cache. I don't understand the
font selection machinery enough to see why is that necessary. But the
upshot of all this is that the face and the font do exist, but the
face-entities for that font are GC'ed, and that triggers the whole
process of discovering the available fonts in the available fontsets
again, each time Emacs displays the character. So if that discovery
process conses a lot, it is likely to trigger GC, which will discard
the font-entities, etc. etc.
next prev parent reply other threads:[~2013-12-13 18:53 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-12 15:32 bug#15876: 24.3.50; Highly degraded performance between rev 114715 and 115006 Sebastien Vauban
2013-11-12 17:11 ` Glenn Morris
[not found] ` <wzwqkdfsts.fsf-iW7gFb+/I3LZHJUXO5efmti2O/JbrIOy@public.gmane.org>
2013-11-12 19:13 ` Sebastien Vauban
2013-11-13 11:43 ` Dani Moncayo
[not found] ` <mailman.5954.1384343055.10748.bug-gnu-emacs@gnu.org>
2013-11-13 13:58 ` Sebastien Vauban
[not found] ` <mailman.5925.1384283656.10748.bug-gnu-emacs@gnu.org>
[not found] ` <mailman.5925.1384283656.10748.bug-gnu-emacs-mXXj517/zsQ@public.gmane.org>
2013-11-13 14:04 ` Sebastien Vauban
2013-11-13 16:11 ` Eli Zaretskii
[not found] ` <83fvr01du4.fsf-mXXj517/zsQ@public.gmane.org>
2013-11-13 20:23 ` Sebastien Vauban
2013-11-13 20:35 ` Eli Zaretskii
2013-11-14 3:05 ` Glenn Morris
[not found] ` <jxeh6j1y4x.fsf-iW7gFb+/I3LZHJUXO5efmti2O/JbrIOy@public.gmane.org>
2013-11-14 10:05 ` Sebastien Vauban
[not found] ` <mailman.6048.1384423574.10748.bug-gnu-emacs@gnu.org>
2013-11-14 10:13 ` Sebastien Vauban
2013-11-14 17:04 ` Glenn Morris
[not found] ` <mailman.6048.1384423574.10748.bug-gnu-emacs-mXXj517/zsQ@public.gmane.org>
2013-11-19 22:52 ` Sebastien Vauban
2013-11-20 1:47 ` Stefan Monnier
2013-11-20 3:53 ` Eli Zaretskii
2013-11-20 3:48 ` Eli Zaretskii
[not found] ` <mailman.6579.1384912163.10748.bug-gnu-emacs@gnu.org>
[not found] ` <mailman.6579.1384912163.10748.bug-gnu-emacs-mXXj517/zsQ@public.gmane.org>
2013-11-20 8:48 ` Sebastien Vauban
[not found] ` <mailman.6575.1384901595.10748.bug-gnu-emacs@gnu.org>
[not found] ` <mailman.6575.1384901595.10748.bug-gnu-emacs-mXXj517/zsQ@public.gmane.org>
2013-11-20 22:32 ` Sebastien Vauban
2013-11-21 3:42 ` Eli Zaretskii
[not found] ` <mailman.6739.1385005456.10748.bug-gnu-emacs@gnu.org>
[not found] ` <mailman.6739.1385005456.10748.bug-gnu-emacs-mXXj517/zsQ@public.gmane.org>
2013-11-26 20:52 ` Sebastien Vauban
2013-11-26 21:04 ` Eli Zaretskii
[not found] ` <mailman.7212.1385499914.10748.bug-gnu-emacs@gnu.org>
[not found] ` <mailman.7212.1385499914.10748.bug-gnu-emacs-mXXj517/zsQ@public.gmane.org>
2013-11-29 21:01 ` Sebastien Vauban
2013-12-01 16:31 ` Eli Zaretskii
2013-12-02 10:45 ` Dmitry Antipov
2013-12-02 11:43 ` Dmitry Antipov
2013-12-02 18:00 ` Eli Zaretskii
2013-12-02 17:52 ` Eli Zaretskii
2013-12-03 9:57 ` Dmitry Antipov
2013-12-03 13:16 ` Eli Zaretskii
2013-12-03 15:09 ` Dmitry Antipov
2013-12-04 17:53 ` Eli Zaretskii
2013-12-05 6:29 ` Dmitry Antipov
2013-12-05 17:36 ` Eli Zaretskii
2013-12-11 6:52 ` Dmitry Antipov
2013-12-11 7:16 ` bug#15876: [SPAM] " Jarek Czekalski
2013-12-11 9:24 ` Dmitry Antipov
2013-12-11 16:28 ` Eli Zaretskii
2013-12-11 18:00 ` Dmitry Antipov
2013-12-11 18:12 ` Eli Zaretskii
2013-12-11 19:50 ` Jan Djärv
2013-12-13 15:22 ` Eli Zaretskii
2013-12-13 16:12 ` Dmitry Antipov
2013-12-13 16:45 ` Stefan Monnier
2013-12-13 18:53 ` Eli Zaretskii [this message]
2013-12-13 18:44 ` Eli Zaretskii
2013-12-16 8:05 ` Dmitry Antipov
2013-12-13 16:50 ` Stefan Monnier
2013-12-13 18:55 ` Eli Zaretskii
2013-12-14 2:13 ` Stefan Monnier
2013-12-14 8:47 ` Jan Djärv
[not found] ` <mailman.7746.1385915595.10748.bug-gnu-emacs@gnu.org>
[not found] ` <mailman.7746.1385915595.10748.bug-gnu-emacs-mXXj517/zsQ@public.gmane.org>
2013-12-01 20:20 ` Sebastien Vauban
2013-12-01 20:37 ` Eli Zaretskii
[not found] ` <mailman.7763.1385930292.10748.bug-gnu-emacs@gnu.org>
[not found] ` <mailman.7763.1385930292.10748.bug-gnu-emacs-mXXj517/zsQ@public.gmane.org>
2013-12-01 21:51 ` Sebastien Vauban
2013-12-02 3:45 ` Eli Zaretskii
[not found] ` <mailman.7786.1385955973.10748.bug-gnu-emacs@gnu.org>
[not found] ` <mailman.7786.1385955973.10748.bug-gnu-emacs-mXXj517/zsQ@public.gmane.org>
2013-12-02 9:29 ` Sebastien Vauban
2013-11-13 16:52 ` Stefan Monnier
2013-11-14 11:03 ` Jarek Czekalski
2013-11-14 16:35 ` Eli Zaretskii
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