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From: "Eric D. Mudama" <edmudama@gmail.com>
To: Roman Zippel <zippel@linux-m68k.org>
Cc: Linus Torvalds <torvalds@osdl.org>,
	David Woodhouse <dwmw2@infradead.org>,
	Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: Kernel SCM saga..
Date: Sat, 9 Apr 2005 10:52:30 -0600	[thread overview]
Message-ID: <311601c905040909525ef8242e@mail.gmail.com> (raw)
In-Reply-To: <Pine.LNX.4.61.0504072318010.15339@scrub.home>

On Apr 8, 2005 4:52 PM, Roman Zippel <zippel@linux-m68k.org> wrote:
> The problem is you pay a price for this. There must be a reason developers
> were adding another GB of memory just to run BK.
> Preserving the complete merge history does indeed make repeated merges
> simpler, but it builds up complex meta data, which has to be managed
> forever. I doubt that this is really an advantage in the long term. I
> expect that we were better off serializing changesets in the main
> repository. For example bk does something like this:
> 
>         A1 -> A2 -> A3 -> BM
>           \-> B1 -> B2 --^
> 
> and instead of creating the merge changeset, one could merge them like
> this:
> 
>         A1 -> A2 -> A3 -> B1 -> B2
> 
> This results in a simpler repository, which is more scalable and which
> is easier for users to work with (e.g. binary bug search).
> The disadvantage would be it will cause more minor conflicts, when changes
> are pulled back into the original tree, but which should be easily
> resolvable most of the time.

The kicker comes that B1 was developed based on A1, so any test
results were based on B1 being a single changeset delta away from A1. 
If the resulting 'BM' fails testing, and you've converted into the
linear model above where B2 has failed, you lose the ability to
isolate B1's changes and where they came from, to revalidate the
developer's results.

With bugs and fixes that can be validated in a few hours, this may not
be a problem, but when chasing a bug that takes days or weeks to
manifest, that a developer swears they fixed, one has to be able to
reproduce their exact test environment.

I believe that flattening the change graph makes history reproduction
impossible, or alternately, you are imposing on each developer to test
the merge results at B1 + A1..3 before submission, but in doing so,
the test time may require additional test periods etc and with
sufficient velocity, might never close.  This is the problem CVS has
if you don't create micro branches for every single modification.

--eric

  parent reply	other threads:[~2005-04-09 16:52 UTC|newest]

Thread overview: 201+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-04-06 15:42 Kernel SCM saga Linus Torvalds
2005-04-06 16:00 ` Greg KH
2005-04-07 16:40   ` Rik van Riel
2005-04-08  0:53     ` Jesse Barnes
2005-04-06 16:09 ` Daniel Phillips
2005-04-06 19:07 ` Jon Smirl
2005-04-06 19:24   ` Matan Peled
2005-04-06 19:49     ` Jon Smirl
2005-04-06 20:34       ` Hua Zhong
2005-04-07  1:31       ` Christoph Lameter
2005-04-06 19:39 ` Paul P Komkoff Jr
2005-04-07  1:40   ` Martin Pool
2005-04-07  1:47     ` Jeff Garzik
2005-04-07  2:26       ` Martin Pool
2005-04-07  2:32         ` David Lang
2005-04-07  5:38           ` Martin Pool
2005-04-07 23:27             ` Linus Torvalds
2005-04-08  5:56               ` Martin Pool
2005-04-08  6:41                 ` Linus Torvalds
2005-04-08  8:38                   ` Andrea Arcangeli
2005-04-08 23:38                     ` Daniel Phillips
2005-04-09  2:54                       ` Andrea Arcangeli
2005-04-09  0:12                     ` Linus Torvalds
2005-04-09  2:27                       ` Andrea Arcangeli
2005-04-09  2:32                         ` David Lang
2005-04-09  3:08                         ` Brian Gerst
2005-04-09  3:15                           ` Andrea Arcangeli
2005-04-09  5:45                         ` Linus Torvalds
2005-04-09 22:55                           ` David S. Miller
2005-04-09 23:13                             ` Linus Torvalds
2005-04-10  0:14                               ` Chris Wedgwood
2005-04-10  1:56                                 ` Paul Jackson
2005-04-10 12:03                                   ` Ingo Molnar
2005-04-10 17:38                                     ` Paul Jackson
2005-04-10 17:46                                       ` Ingo Molnar
2005-04-10 17:56                                         ` Paul Jackson
2005-04-10  0:22                             ` Paul Jackson
2005-04-10 11:33                             ` Ingo Molnar
2005-04-10 17:55                         ` Matthias Andree
2005-04-09 16:33                       ` Roman Zippel
2005-04-09 23:31                         ` Tupshin Harper
2005-04-10 17:24                         ` Code snippet to reconstruct ancestry graph from bk repo Paul P Komkoff Jr
2005-04-10 18:19                           ` Roman Zippel
2005-04-08 16:46                   ` Kernel SCM saga Catalin Marinas
2005-04-07  8:14           ` Magnus Damm
2005-04-07  7:53       ` Zwane Mwaikambo
2005-04-07  3:35     ` Daniel Phillips
2005-04-07 15:08       ` Daniel Phillips
2005-04-07  6:36   ` bert hubert
2005-04-06 23:22 ` Jon Masters
2005-04-07  6:51 ` Paul Mackerras
2005-04-07  7:48   ` Arjan van de Ven
2005-04-07 15:10   ` Linus Torvalds
2005-04-07 17:00     ` Daniel Phillips
2005-04-07 17:38       ` Linus Torvalds
2005-04-07 17:47         ` Chris Wedgwood
2005-04-07 18:06         ` Magnus Damm
2005-04-07 18:36         ` Daniel Phillips
2005-04-08  3:35         ` Jeff Garzik
2005-04-07 19:56       ` Sam Ravnborg
2005-04-07 23:21     ` Dave Airlie
2005-04-07  7:18 ` David Woodhouse
2005-04-07  8:50   ` Andrew Morton
2005-04-07  9:20     ` Paul Mackerras
2005-04-07  9:46       ` Andrew Morton
2005-04-07 11:17         ` Paul Mackerras
2005-04-07 10:41       ` Geert Uytterhoeven
2005-04-07  9:25     ` David Woodhouse
2005-04-07  9:49       ` Andrew Morton
2005-04-07  9:55       ` Russell King
2005-04-07 10:11         ` David Woodhouse
2005-04-07  9:40     ` David Vrabel
2005-04-07  9:24   ` Sergei Organov
2005-04-07 10:30     ` Matthias Andree
2005-04-07 10:54       ` Andrew Walrond
2005-04-09 16:17       ` David Roundy
2005-04-10  9:24         ` Giuseppe Bilotta
2005-04-10 13:51           ` David Roundy
2005-04-07 15:32   ` Linus Torvalds
2005-04-07 17:09     ` Daniel Phillips
2005-04-07 17:10     ` Al Viro
2005-04-07 17:47       ` Linus Torvalds
2005-04-07 18:04         ` Jörn Engel
2005-04-07 18:27           ` Daniel Phillips
2005-04-07 20:54           ` Arjan van de Ven
2005-04-08  3:41         ` Jeff Garzik
2005-04-07 17:52       ` Bartlomiej Zolnierkiewicz
2005-04-07 17:54       ` Daniel Phillips
2005-04-07 18:13         ` Dmitry Yusupov
2005-04-07 18:29           ` Daniel Phillips
2005-04-10 22:33             ` Troy Benjegerdes
2005-04-11  0:00               ` Christian Parpart
2005-04-08 17:24         ` Jon Masters
2005-04-08 22:05           ` Daniel Phillips
2005-04-08 22:52     ` Roman Zippel
2005-04-08 23:46       ` Tupshin Harper
2005-04-09  1:00         ` Roman Zippel
2005-04-09  1:23           ` Tupshin Harper
2005-04-09 16:52       ` Eric D. Mudama [this message]
2005-04-09 17:40         ` Roman Zippel
2005-04-09 18:56           ` Ray Lee
2005-04-07  7:44 ` Jan Hudec
2005-04-08  6:14   ` Matthias Urlichs
2005-04-09  1:01   ` Marcin Dalecki
2005-04-09  8:32     ` Jan Hudec
2005-04-11  2:26     ` Miles Bader
2005-04-11  2:56       ` Marcin Dalecki
2005-04-11  6:36         ` Jan Hudec
2005-04-07 10:56 ` Andrew Walrond
2005-04-08  0:57 ` Ian Wienand
2005-04-08  4:13 ` Chris Wedgwood
2005-04-08  4:42   ` Linus Torvalds
2005-04-08  5:04     ` Chris Wedgwood
2005-04-08  5:14       ` H. Peter Anvin
2005-04-08  7:05         ` Rogan Dawes
2005-04-08  7:21           ` Daniel Phillips
2005-04-08  7:49             ` H. Peter Anvin
2005-04-08  7:14     ` Andrea Arcangeli
2005-04-08 12:02       ` Matthias Andree
2005-04-08 12:21         ` Florian Weimer
2005-04-08 14:26       ` Linus Torvalds
2005-04-08 16:15         ` Matthias-Christian Ott
2005-04-08 17:14           ` Linus Torvalds
2005-04-08 17:15             ` Chris Wedgwood
2005-04-08 17:46               ` Linus Torvalds
2005-04-08 18:05                 ` Chris Wedgwood
2005-04-08 19:03                   ` Linus Torvalds
2005-04-08 19:16                     ` Chris Wedgwood
2005-04-08 19:38                       ` Florian Weimer
2005-04-08 19:48                         ` Chris Wedgwood
2005-04-08 19:39                       ` Linus Torvalds
2005-04-08 20:11                         ` Uncached stat performace [ Was: Re: Kernel SCM saga.. ] Ragnar Kjørstad
2005-04-08 20:14                           ` Chris Wedgwood
2005-04-08 20:50                       ` Kernel SCM saga Luck, Tony
2005-04-08 21:27                         ` Linus Torvalds
2005-04-09 17:14                           ` Roman Zippel
2005-04-09  7:20                     ` Willy Tarreau
2005-04-09 15:15                     ` Paul Jackson
2005-04-08 17:25             ` Matthias-Christian Ott
2005-04-08 18:14               ` Linus Torvalds
2005-04-08 18:28                 ` Jon Smirl
2005-04-08 18:58                   ` Florian Weimer
2005-04-09  1:11                   ` Marcin Dalecki
2005-04-09  1:50                     ` David Lang
2005-04-09 22:12                       ` Florian Weimer
2005-04-08 19:16                 ` Matthias-Christian Ott
2005-04-08 19:32                   ` Linus Torvalds
2005-04-08 19:44                     ` Matthias-Christian Ott
2005-04-09  1:09                 ` Marcin Dalecki
2005-04-08 17:35             ` Jeff Garzik
2005-04-08 18:47               ` Linus Torvalds
2005-04-08 18:56                 ` Chris Wedgwood
2005-04-09  7:37                   ` Willy Tarreau
2005-04-09  7:47                     ` Neil Brown
2005-04-09  8:00                       ` Willy Tarreau
2005-04-09  9:34                         ` Neil Brown
2005-04-09 15:40                 ` Paul Jackson
2005-04-09 16:16                   ` Linus Torvalds
2005-04-09 17:15                     ` Paul Jackson
2005-04-09 17:35                     ` Paul Jackson
2005-04-09  1:04             ` Marcin Dalecki
2005-04-09 15:42               ` Paul Jackson
2005-04-09 18:45                 ` Marcin Dalecki
2005-04-09  1:00           ` Marcin Dalecki
2005-04-09  1:09             ` Chris Wedgwood
2005-04-09  1:21               ` Marcin Dalecki
2005-04-08  7:17     ` ross
2005-04-08 15:50       ` Linus Torvalds
2005-04-09  2:53         ` Petr Baudis
2005-04-09  7:08           ` Randy.Dunlap
2005-04-09 18:06             ` [PATCH] " Petr Baudis
2005-04-10  1:01           ` Phillip Lougher
2005-04-10  1:42             ` Petr Baudis
2005-04-10  1:57               ` Phillip Lougher
2005-04-09 15:50         ` Paul Jackson
2005-04-09 16:26           ` Linus Torvalds
2005-04-09 17:08             ` Paul Jackson
2005-04-10  3:41             ` Paul Jackson
2005-04-10  8:39             ` David Lang
2005-04-10  9:40               ` Junio C Hamano
2005-04-10 16:46                 ` Bill Davidsen
2005-04-10 17:50                   ` Paul Jackson
2005-04-12 23:20                     ` Pavel Machek
2005-04-08  7:34     ` Marcel Lanz
2005-04-08  9:23       ` Geert Uytterhoeven
2005-04-08  8:38     ` Matt Johnston
2005-04-12  7:14     ` Kernel SCM saga.. (bk license?) Kedar Sovani
2005-04-12  9:34       ` Catalin Marinas
2005-04-13  4:04       ` Ricky Beam
2005-04-08 11:42   ` Kernel SCM saga Catalin Marinas
     [not found] <Pine.LNX.4.58.0504060800280.2215 () ppc970 ! osdl ! org>
2005-04-06 21:13 ` kfogel
2005-04-06 22:39   ` Jeff Garzik
2005-04-09  1:00   ` Marcin Dalecki
2005-04-08 22:27 Rajesh Venkatasubramanian
2005-04-08 23:29 ` Linus Torvalds
2005-04-09  0:29   ` Linus Torvalds
2005-04-09 16:20   ` Paul Jackson
2005-04-09  4:06 Walter Landry
2005-04-09 11:02 Samium Gromoff
2005-04-09 11:29 Samium Gromoff
2005-04-10  4:20 Albert Cahalan

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