From: Wincent Colaiuta <win@wincent.com>
To: Walter Bright <boost@digitalmars.com>
Cc: git@vger.kernel.org
Subject: Re: [RFC] Convert builin-mailinfo.c to use The Better String Library.
Date: Fri, 7 Sep 2007 13:52:01 +0200 [thread overview]
Message-ID: <FEA805F3-A6BA-4C76-B2C7-E28C00FDD801@wincent.com> (raw)
In-Reply-To: <fbr2iv$ugg$1@sea.gmane.org>
El 7/9/2007, a las 10:36, Walter Bright escribió:
> Wincent Colaiuta wrote:
>> Git is all about speed, and C is the best choice for speed,
>> especially in context of Git's workload.
>
> I can appreciate that. I originally got into writing compilers
> because my game (Empire) ran too slowly and I thought the existing
> compilers could be dramatically improved.
>
> And technically, yes, you can write code in C that is >= the speed
> of any other language (other than asm). But practically, this isn't
> necessarily so, for the following reasons:
>
> 1) You wind up having to implement the complex, dirty details of
> things yourself. The consequences of this are:
>
> a) you pick a simpler algorithm (which is likely less efficient
> - I run across bubble sorts all the time in code)
>
> b) once you implement, tune, and squeeze all the bugs out of
> those complex, dirty details, you're reluctant to change it. You're
> reluctant to try a different algorithm to see if it's faster. I've
> seen this effect a lot in my own code. (I translated a large body
> of my own C++ code that I'd spent months tuning to D, and quickly
> managed to get significantly more speed out of it, because it was
> much simpler to try out different algorithms/data structures.)
While I accept that this is generally true, I think Git is somewhat
of a special case. From a design perspective the data structures and
algorithms are remarkably simple -- therein lies its elegance. I
think it's precisely the kind of problem that can be tackled well
with a close-to-the-metal language like C.
> 2) Garbage collection has an interesting and counterintuitive
> consequence. If you compare n malloc/free's with n gcnew/
> collections, the malloc/free will come out faster, and you conclude
> that gc is slow. But that misses one huge speed advantage of gc -
> you can do FAR fewer allocations! For example, I've done a lot of
> string manipulating programs in C. The basic problem is keeping
> track of who owns each string. This is done by, when in doubt, make
> a copy of the string.
>
> But if you have gc, you don't worry about who owns the string. You
> just make another pointer to it. D takes this a step further with
> the concept of array slicing, where one creates windows on existing
> arrays, or windows on windows on windows, and no allocations are
> ever done. It's just pointer fiddling.
This mirrors my experience in desktop application development.
Despite GC being "slower" the app actually runs faster and a lot of
nasty problems (shared resources, locking etc) just magically go
away. Development is easier too.
But once again I think Git falls into a special category where the
design makes the "hassle" of developing in C worth it.
Wincent
next prev parent reply other threads:[~2007-09-07 11:52 UTC|newest]
Thread overview: 102+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-04 20:50 [RFC] Convert builin-mailinfo.c to use The Better String Library Lukas Sandström
2007-09-04 21:38 ` Alex Riesen
2007-09-04 23:01 ` Pierre Habouzit
2007-09-05 14:54 ` Kristian Høgsberg
2007-09-05 17:29 ` Matthieu Moy
2007-09-06 2:30 ` Miles Bader
2007-09-06 4:48 ` Dmitry Kakurin
2007-09-06 4:59 ` Shawn O. Pearce
2007-09-06 9:12 ` Andreas Ericsson
2007-09-06 9:35 ` Junio C Hamano
2007-09-06 10:21 ` Andreas Ericsson
2007-09-06 9:52 ` David Kastrup
2007-09-06 5:03 ` Miles Bader
2007-09-06 12:08 ` Johannes Schindelin
2007-09-06 17:50 ` Linus Torvalds
2007-09-07 0:21 ` Dmitry Kakurin
2007-09-07 0:38 ` Linus Torvalds
2007-09-07 1:08 ` Dmitry Kakurin
2007-09-07 1:27 ` Linus Torvalds
2007-09-07 3:09 ` Dmitry Kakurin
2007-09-07 5:48 ` David Symonds
2007-09-07 6:15 ` Theodore Tso
2007-09-20 14:06 ` Steven Burns
2007-09-20 14:56 ` Andreas Ericsson
2007-09-07 6:31 ` Andreas Ericsson
2007-09-07 22:17 ` Dmitry Kakurin
2007-09-07 22:28 ` David Kastrup
2007-09-08 0:37 ` Dmitry Kakurin
2007-09-08 6:25 ` David Kastrup
2007-09-09 0:29 ` Andreas Ericsson
2007-09-07 6:52 ` David Kastrup
2007-09-07 10:28 ` Johannes Schindelin
2007-09-07 10:26 ` Johannes Schindelin
2007-09-07 6:50 ` David Kastrup
2007-09-07 1:12 ` Linus Torvalds
2007-09-07 1:40 ` alan
2007-09-07 5:09 ` Walter Bright
2007-09-07 7:40 ` David Kastrup
2007-09-07 8:15 ` Walter Bright
2007-09-07 8:26 ` David Kastrup
2007-09-07 9:14 ` Walter Bright
2007-09-07 9:31 ` David Kastrup
2007-09-07 20:22 ` Walter Bright
2007-09-07 20:27 ` David Kastrup
2007-09-07 23:16 ` Walter Bright
2007-09-08 23:50 ` Andreas Ericsson
2007-09-09 0:37 ` Pierre Habouzit
2007-09-09 1:36 ` Andreas Ericsson
2007-09-07 11:36 ` Wincent Colaiuta
2007-09-07 9:41 ` Pierre Habouzit
2007-09-07 19:03 ` Walter Bright
2007-09-07 19:31 ` David Kastrup
2007-09-07 20:49 ` Walter Bright
2007-09-07 19:41 ` Pierre Habouzit
2007-09-07 19:51 ` David Kastrup
2007-09-07 19:59 ` Pierre Habouzit
2007-09-07 20:40 ` Walter Bright
2007-09-07 20:56 ` Pierre Habouzit
2007-09-07 22:54 ` Walter Bright
2007-09-08 0:56 ` John 'Z-Bo' Zabroski
2007-09-08 6:36 ` David Kastrup
2007-09-19 19:56 ` Steven Burns
2007-09-07 3:06 ` Wincent Colaiuta
2007-09-07 4:06 ` Paul Wankadia
2007-09-07 4:30 ` Nicolas Pitre
2007-09-07 9:19 ` Wincent Colaiuta
2007-09-07 6:25 ` Andreas Ericsson
2007-09-07 10:56 ` Johannes Schindelin
2007-09-07 11:54 ` Andreas Ericsson
2007-09-07 12:33 ` Wincent Colaiuta
2007-09-07 12:55 ` Karl Hasselström
2007-09-07 13:58 ` Andreas Ericsson
2007-09-07 14:13 ` Wincent Colaiuta
2007-09-09 0:09 ` Andreas Ericsson
2007-09-07 16:09 ` David Kastrup
2007-09-07 11:30 ` Wincent Colaiuta
2007-09-07 8:36 ` Walter Bright
2007-09-07 9:41 ` Andreas Ericsson
2007-09-07 19:23 ` Walter Bright
2007-09-07 19:40 ` David Kastrup
2007-09-09 0:25 ` Andreas Ericsson
2009-09-17 16:23 ` Bernd Jendrissek
2007-09-07 11:52 ` Wincent Colaiuta [this message]
2007-09-07 19:25 ` Walter Bright
2007-09-22 16:52 ` Steven Burns
2007-09-07 6:47 ` David Kastrup
2007-09-07 7:41 ` Andy Parkins
2007-09-07 8:08 ` David Kastrup
2007-09-07 10:21 ` Johannes Schindelin
2007-09-08 0:32 ` Dmitry Kakurin
2007-09-08 6:24 ` David Kastrup
2007-09-08 23:25 ` Alex Riesen
2007-09-24 13:41 ` figo
2007-09-24 13:57 ` David Kastrup
2007-09-25 19:19 ` Steven Burns
2007-09-25 19:55 ` David Kastrup
2012-05-22 18:30 ` Syed M Raihan
2010-06-10 19:12 ` Ian Molton
2010-06-11 12:23 ` Jakub Narebski
2010-06-11 13:33 ` Dario Rodriguez
2007-09-05 15:27 ` Kristian Høgsberg
2007-09-07 10:47 ` Lukas Sandström
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