From: Leo Liu <sdl.web@gmail.com>
To: emacs-devel@gnu.org
Subject: Re: why is reverse a string in-place so much slower than a vector?
Date: Fri, 25 Apr 2014 16:17:42 +0800 [thread overview]
Message-ID: <m338h1n7q1.fsf@gmail.com> (raw)
In-Reply-To: m37g6dn7z3.fsf@gmail.com
On 2014-04-25 16:12 +0800, Leo Liu wrote:
> (defun rev (a)
> (let ((l (length a)))
> (dotimes (i (floor l 2) a)
> (cl-rotatef (aref a i) (aref a (1- (- l i)))))))
Sorry didn't finish the post.
Assume we are in a buffer visiting subr.el:
(benchmark-run 1 (rev (buffer-string)))
(11.774416366 1 0.060193897999999635)
(benchmark-run 1 (rev (cl-coerce (buffer-string) 'vector)))
(0.067042623 0 0.0)
So why is this so much slower on string?
Leo
next prev parent reply other threads:[~2014-04-25 8:17 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-25 8:12 why is reverse a string in-place so much slower than a vector? Leo Liu
2014-04-25 8:17 ` Leo Liu [this message]
2014-04-25 8:55 ` Rüdiger Sonderfeld
2014-04-25 9:14 ` Andreas Schwab
2014-04-25 9:35 ` Leo Liu
2014-04-25 11:00 ` Andreas Schwab
2014-04-26 0:19 ` Leo Liu
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