git@vger.kernel.org list mirror (unofficial, one of many)
 help / color / mirror / code / Atom feed
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

  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 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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

  List information: http://vger.kernel.org/majordomo-info.html

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=FEA805F3-A6BA-4C76-B2C7-E28C00FDD801@wincent.com \
    --to=win@wincent.com \
    --cc=boost@digitalmars.com \
    --cc=git@vger.kernel.org \
    --subject='Re: [RFC] Convert builin-mailinfo.c to use The Better String Library.' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Code repositories for project(s) associated with this inbox:

	https://80x24.org/mirrors/git.git

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).