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From: Eli Zaretskii <eliz@gnu.org>
To: "Andreas Röhler" <andreas.roehler@online.de>
Cc: emacs-devel@gnu.org
Subject: Re: C and Emacs Lisp code parts
Date: Fri, 01 Jul 2016 16:01:11 +0300	[thread overview]
Message-ID: <83twg9tsvc.fsf@gnu.org> (raw)
In-Reply-To: <54f5d80c-f20b-31aa-b438-401984fcb5b8@online.de> (message from Andreas Röhler on Fri, 1 Jul 2016 14:25:22 +0200)

> Cc: emacs-devel@gnu.org
> From: Andreas Röhler <andreas.roehler@online.de>
> Date: Fri, 1 Jul 2016 14:25:22 +0200
> 
> On 01.07.2016 11:25, Eli Zaretskii wrote:
> >
> > So yes, we need numbers to make rational decisions about this.
> 
> Sorry, but that's irrational.

??? Comparing without numbers, based on "feelings", is irrational!

It is a well-known fact that reasoning about code optimizations
without measurements is a fallacy that causes optimizations in wrong
places.

> Compare doesn't need numbers. To compare implementations in C an
> exec is needed - which doesn't exist yet. If written, the reason
> basically is gone, because C will be faster - unless something went
> wrong, which is a case for debugging rather than benchmarks.

I'm not against writing it, I'm just saying that before accepting a C
implementation instead of a Lisp one, we should consider the speedup
factor, because rewriting in C has its downsides (which you mentioned)
that have to be weighed against the advantages.



  reply	other threads:[~2016-07-01 13:01 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-01  8:03 C and Emacs Lisp code parts Andreas Röhler
2016-07-01  8:13 ` Eli Zaretskii
2016-07-01  8:39   ` Andreas Röhler
2016-07-01  9:16     ` Alan Mackenzie
2016-07-01 12:07       ` Andreas Röhler
2016-07-01 13:04         ` Eli Zaretskii
2016-07-05 22:48           ` John Wiegley
2016-07-06  7:25             ` Andreas Röhler
2016-07-06  7:31               ` Andreas Röhler
2016-07-06 15:27               ` Phillip Lord
2016-07-01  9:17     ` John Wiegley
2016-07-01 13:26       ` Andreas Röhler
2016-07-01  9:25     ` Eli Zaretskii
2016-07-01 12:25       ` Andreas Röhler
2016-07-01 13:01         ` Eli Zaretskii [this message]
2016-07-01 13:05         ` Andy Moreton
2016-07-01 15:14           ` Karl Fogel
2016-07-01 16:52             ` Andreas Röhler
2016-07-01 17:13               ` Eli Zaretskii
2016-07-01 17:36                 ` Andreas Röhler
2016-07-01 17:38                   ` Eli Zaretskii
2016-07-02 16:41                     ` Fabrice Popineau
2016-07-02 17:16                       ` Eli Zaretskii
2016-07-01 17:55                   ` Alan Mackenzie
2016-07-01 18:31                     ` Andreas Röhler
2016-07-01 18:57                       ` Alan Mackenzie
2016-07-01 20:04                         ` Andreas Röhler
2016-07-01 20:31                           ` Davis Herring
2016-07-02  6:34                             ` Andreas Röhler
2016-07-02 11:29                               ` Paul Eggert
2016-07-05 17:02                               ` Davis Herring
2016-07-05 19:35                                 ` Andreas Röhler
2016-07-02  6:32                           ` Eli Zaretskii
2016-07-02  7:01                             ` Andreas Röhler
2016-07-02  8:15                               ` Eli Zaretskii
2016-07-02  3:32 ` Tom Tromey
2016-07-02  3:42   ` Clément Pit--Claudel

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