GNU bug report logs - #52753
29.0.50; Printing long list-like structures fails

Previous Next

Package: emacs;

Reported by: Ihor Radchenko <yantar92 <at> gmail.com>

Date: Thu, 23 Dec 2021 11:06:01 UTC

Severity: normal

Found in version 29.0.50

Done: Mattias Engdegård <mattiase <at> acm.org>

Bug is archived. No further changes may be made.

Full log

View this message in rfc822 format

From: Mattias Engdegård <mattiase <at> acm.org>
To: Ihor Radchenko <yantar92 <at> gmail.com>
Cc: 52753 <at> debbugs.gnu.org
Subject: bug#52753: 29.0.50; Printing long list-like structures fails
Date: Sun, 30 Jan 2022 11:16:24 +0100

30 jan. 2022 kl. 10.16 skrev Ihor Radchenko <yantar92 <at> gmail.com>:

> the speedup will only be relevant when
> explicitly allocated C arrays are used to store B-tree segments: all the
> tree data must be physically located within continuous segment of RAM
> address space.

Lisp vectors are contiguous in memory, and your keys are small integers and thus unboxed.

> People do say
> that splay trees can be good, but never have real world examples.

The trouble with splay trees seems to be that they require a very skewed access distribution to be worthwhile -- every read of something that isn't the latest accessed element becomes a tree modification. But that implies that the access pattern exhibits spatial and/or temporal locality, which makes caching an attractive alternative (explicit or those in your computer).
This bug report was last modified 2 years and 349 days ago.

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.