From: Andreas Politz <politza@hochschule-trier.de>
To: Stefan Monnier <monnier@iro.umontreal.ca>
Cc: emacs-devel@gnu.org
Subject: Re: Overlays as an AA-tree
Date: Fri, 24 Feb 2017 09:43:16 +0100 [thread overview]
Message-ID: <87vas07zdn.fsf@luca> (raw)
In-Reply-To: <jwvefyrml0q.fsf-monnier+gmane.emacs.devel@gnu.org> (Stefan Monnier's message of "Tue, 21 Feb 2017 14:18:44 -0500")
Stefan Monnier <monnier@iro.umontreal.ca> writes:
> Is there a reason why "struct Lisp_Overlay" and "struct interval_node"
> are separate?
The main reason is that it can't be used for anything else, once the
nodes are all Lisp_Overlay's . There are at least two other balanced
trees in Emacs and maybe, at some time, there should be only one. (Also,
initially I didn't need to worry about the Emacs side.)
> [...] That means an overlay takes up about twice the size of a marker.
>
> Should we then (re)implement markers as degenerate overlays? [it's not
> as simple as it sounds: contrary to overlays markers can be GC'd if not
> referenced, so we'd need to add support for "weakly referenced
> overlays". Furthermore markers are used to speed up byte<->char
> conversions, so we'd need to replace that code accordingly. ]
Could we use the end attribute as byte value ? Also, does Emacs create
extra markers for this lookup or can this be called a "opportunistic
optimization" ?
I did some comparisons between marker and empty overlays regarding
insertions and deletions. *-before and *-after insert/delete at
point-min resp. -max, scatter means randomly. In each case 4096
single character were inserted/deleted.
===============================================
32K 64K
------------ -------------
4096 edits ma ov ma ov
-----------------------------------------------
insert-before 4.20 0.22 16.66 0.44
insert-after 3.28 0.12 12.96 0.20
insert-scatter 4.84 0.21 18.74 0.37
delete-before 4.09 60.32 16.16 277.75
delete-after 3.75 35.49 14.74 160.91
delete-scatter 4.02 0.36 15.64 0.86
===============================================
As you can see the delete-before/after cases are still somewhat
problematic. Maybe we should think about using a single node per
position combined with a list. What do you think ?
-ap
next prev parent reply other threads:[~2017-02-24 8:43 UTC|newest]
Thread overview: 110+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-20 10:32 Overlays as an AA-tree Joakim Jalap
2016-09-20 12:14 ` Clément Pit--Claudel
2016-09-20 12:43 ` Lars Ingebrigtsen
2016-09-20 16:19 ` Joakim Jalap
2016-09-20 23:19 ` Richard Stallman
2016-09-20 14:40 ` Eli Zaretskii
2016-09-20 17:13 ` Joakim Jalap
2016-09-21 16:14 ` Eli Zaretskii
2016-09-22 10:35 ` Joakim Jalap
2016-09-22 12:24 ` Stefan Monnier
2016-09-21 14:52 ` Stefan Monnier
2016-09-21 15:58 ` Eli Zaretskii
2016-09-21 16:24 ` Stefan Monnier
2016-09-21 16:43 ` Eli Zaretskii
2016-09-21 18:41 ` Stefan Monnier
2016-09-21 19:28 ` Eli Zaretskii
2016-09-22 10:35 ` Joakim Jalap
2016-09-22 12:17 ` Stefan Monnier
2016-09-22 20:11 ` Joakim Jalap
2016-09-23 1:29 ` Stefan Monnier
2016-09-27 6:26 ` Joakim Jalap
2016-09-27 11:50 ` Stefan Monnier
2016-09-27 14:38 ` Eli Zaretskii
2016-09-27 16:07 ` Joakim Jalap
2016-11-21 17:32 ` Clément Pit--Claudel
2016-11-22 8:09 ` Joakim Jalap
2016-11-22 13:44 ` Stefan Monnier
2016-11-23 6:58 ` Joakim Jalap
2016-11-22 13:44 ` Clément Pit--Claudel
2016-11-22 13:55 ` Evgeny Roubinchtein
2016-11-23 7:16 ` Joakim Jalap
2016-11-23 15:42 ` Eli Zaretskii
2016-11-23 16:06 ` Stefan Monnier
2016-11-24 18:33 ` Evgeny Roubinchtein
2016-11-23 7:13 ` Joakim Jalap
2017-02-03 8:49 ` Andreas Politz
2017-02-03 9:13 ` Eli Zaretskii
2017-02-03 10:24 ` Andreas Politz
2017-02-03 11:33 ` Joakim Jalap
2017-02-03 12:44 ` Andreas Politz
2017-02-03 14:11 ` Joakim Jalap
2017-02-03 15:02 ` Andreas Politz
2017-02-03 15:23 ` Joakim Jalap
2017-02-03 15:54 ` Andreas Politz
2017-02-04 21:22 ` Stefan Monnier
2017-02-04 23:10 ` Andreas Politz
2017-02-06 9:56 ` Joakim Jalap
2017-02-06 11:33 ` Andreas Politz
2017-02-06 15:33 ` Joakim Jalap
2017-02-06 15:46 ` Stefan Monnier
2017-02-06 16:52 ` Joakim Jalap
2017-02-06 17:34 ` Stefan Monnier
2017-02-06 17:32 ` Andreas Politz
2017-02-07 12:35 ` Andreas Politz
2017-02-07 14:46 ` Joakim Jalap
2017-02-07 22:00 ` Andreas Politz
2017-02-08 0:36 ` Andreas Politz
2017-02-08 6:53 ` Joakim Jalap
2017-02-08 7:34 ` Andreas Politz
2017-02-08 8:18 ` Joakim Jalap
2017-02-08 8:44 ` Andreas Politz
2017-02-08 16:34 ` Andreas Politz
2017-02-08 17:38 ` Eli Zaretskii
2017-02-08 13:04 ` Stefan Monnier
2017-02-08 22:27 ` Andreas Politz
2017-02-08 22:34 ` Stefan Monnier
2017-02-09 9:34 ` Andreas Politz
2017-02-09 10:05 ` Joakim Jalap
2017-02-09 10:19 ` Andreas Politz
2017-02-13 3:44 ` Andreas Politz
2017-02-13 6:11 ` Eli Zaretskii
2017-02-13 9:04 ` Andreas Politz
2017-02-13 14:36 ` Eli Zaretskii
2017-02-14 10:07 ` Andreas Politz
2017-02-17 4:58 ` Andreas Politz
2017-02-17 7:12 ` Eli Zaretskii
2017-02-19 22:39 ` Andreas Politz
2017-02-19 23:10 ` Stefan Monnier
2017-02-19 23:44 ` Andreas Politz
2017-02-20 15:34 ` Eli Zaretskii
2017-02-21 6:56 ` Andreas Politz
2017-02-21 15:11 ` Stefan Monnier
2017-02-21 18:26 ` Andreas Politz
2017-02-21 19:18 ` Stefan Monnier
2017-02-21 23:36 ` Andreas Politz
2017-02-24 8:43 ` Andreas Politz [this message]
2017-04-08 13:28 ` Clément Pit-Claudel
2017-05-03 19:20 ` Andreas Politz
2017-05-03 19:40 ` Stefan Monnier
2017-05-05 20:39 ` Andreas Politz
2017-05-04 0:54 ` Clément Pit-Claudel
2017-05-05 20:10 ` Andreas Politz
2017-05-05 22:22 ` Clément Pit-Claudel
2017-05-06 8:05 ` Andreas Politz
2017-05-04 14:21 ` Eli Zaretskii
2017-05-05 20:08 ` Andreas Politz
2017-05-05 21:41 ` Eli Zaretskii
2017-09-24 13:09 ` Clément Pit-Claudel
2017-10-04 8:17 ` Andreas Politz
2017-10-04 9:22 ` Eli Zaretskii
2017-10-04 20:36 ` Andreas Politz
2017-02-14 0:45 ` Richard Stallman
2017-02-14 8:32 ` Andreas Politz
2017-02-06 13:51 ` Stefan Monnier
2017-02-06 14:26 ` Andreas Politz
2017-02-06 15:06 ` Stefan Monnier
2017-02-06 15:40 ` Joakim Jalap
2017-02-06 16:24 ` Clément Pit-Claudel
2017-02-03 13:55 ` Stefan Monnier
2017-02-03 15:14 ` Andreas Politz
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