[darcs-users] [patch351] Optimize darcs diff.

[Petr Ročkai]

New submission from Petr Ročkai <me at mornfall.net>:

Hi,

I have changed the diff code to only write those files that actually changed in
the temporary locations. On my other project (less than 1000 working copy
files):

(with cold cache)
head: darcs diff  1,09s user 0,58s system 9% cpu 16,752 total
now:  darcs diff  0,14s user 0,04s system 6% cpu 2,978 total

(with hot cache)
head: darcs diff  0,36s user 0,18s system 98% cpu 0,548 total
now:  darcs diff  0,06s user 0,01s system 86% cpu 0,078 total

Yours,
   Petr.

PS: Presumably, it would be yet more efficient to not write anything out and
not call an external diff tool in cases that can be avoided. I might release a
cabal library for formatting diffs, so if we know how to handle the options and
no explicit --diff-command is given, we could just do the diffing internally. I
guess the win is not going to be as big as from this change, though.

PPS: The bundle depends on the path refactor one, since I became too frustrated
with converting the paths half dozen times to satisfy the typechecker (I gave
up facing a FilePath -> SubPath conversion, which would probably require
another couple lines of path conversion code...)

8 patches for repository http://darcs.net/:

Wed Aug 11 17:39:29 CEST 2010  Petr Rockai <me at mornfall.net>
  * First stab at a hashed-storage 0.6 port.

Thu Aug 12 00:09:46 CEST 2010  Petr Rockai <me at mornfall.net>
  * Make SubPath just another alias for Relative.

Wed Aug 11 21:45:04 CEST 2010  Petr Rockai <me at mornfall.net>
  * Make FileName an alias to Relative (from Hashed.Storage.Path).

Thu Aug 12 00:02:43 CEST 2010  Petr Rockai <me at mornfall.net>
  * Replace FilePath with FileName in SelectChanges and ChooseTouching.

Thu Aug 12 00:16:21 CEST 2010  Petr Rockai <me at mornfall.net>
  * Introduce a new Darcs.Path module to centralise path handling.

Thu Aug 12 00:36:15 CEST 2010  Petr Rockai <me at mornfall.net>
  * Merge Darcs.Patch.FileName into Darcs.Path.

Thu Aug 12 00:47:39 CEST 2010  Petr Rockai <me at mornfall.net>
  * Remove the now-redundant sp2fn.

Wed Aug 18 22:53:38 CEST 2010  Petr Rockai <me at mornfall.net>
  * Optimize darcs diff.

----------
files: first-stab-at-a-hashed_storage-0_6-port_.dpatch, unnamed
messages: 12224
nosy: mornfall
status: needs-review
title: Optimize darcs diff.

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Darcs bug tracker <bugs at darcs.net>
<http://bugs.darcs.net/patch351>
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