From: Eli Zaretskii <eliz@gnu.org>
Date: Sat, 21 Aug 2021 06:33:34 +0000 (+0300)
Subject: * etc/TODO: Entry about markers being non-scalable.  (Bug#49127)
X-Git-Tag: emacs-28.0.90~1406
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=77d0ab967d1a2a0cb3f2164583fd4f1a99331c58;p=emacs.git

* etc/TODO: Entry about markers being non-scalable.  (Bug#49127)
---

diff --git a/etc/TODO b/etc/TODO
index 1d6824c470a..e199e6b02d6 100644
--- a/etc/TODO
+++ b/etc/TODO
@@ -1538,6 +1538,14 @@ cannot represent in Unicode.
 
 *** Performance
 
+**** Make the implementation of markers more eifficient
+Markers are implemented as a non-sorted singly linked list of markers.
+This makes them scale badly when thousands of markers are created in a
+buffer for some purpose, because some low-level primitives in Emacs
+traverse the markers' list (e.g., when converting between character
+and byte positions), and also because searching for a marker (e.g.,
+with 'buffer-has-markers-at') becomes very slow.
+
 **** Explore whether overlay-recenter can cure overlays performance problems
 
 **** Cache schemas.  Need to have list of files and mtimes