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Re: heads-up: git-index-pack in "next" is broken

From
DLDavide Libenzi <davidel@xmailserver.org>
Date
Oct 18, 2006, 06:09 UTC
Message-ID
<Pine.LNX.4.64.0610172242430.17253@alien.or.mcafeemobile.com>
In-Reply-To
<Pine.LNX.4.64.0610171959180.3962@g5.osdl.org>
On Tue, 17 Oct 2006, Linus Torvalds wrote:
Show 8 quoted lines
> > Does this mean that, with your own change to xdiff that has just been 
> > committed, you actually created a "problem"?  Because this is a change 
> > that creates different behaviors whether a 32-bit or 64-bit architecture 
> > is used, Right?
> 
> If you go back to that discussion, I actually pointed out several times 
> that the whole bug _was_ actually introduced exactly because the xdiff 
> code used things that behave differently depending on word-size.

Ehm, I think there's a little bit of confusion. The incorrect golden ratio prime selection for 64 bits machines was coalescing hash indexes into a very limited number of buckets, hence creating very bad performance on diff operations. The result of the diff would have been exacly the same, just coming out after the time for a cup of coffee and a croissant ;)

> So the bug in xdiff was _exactly_ that somebody - totally incorrectly - 
> thought it should work "better" on 64-bits. 

Haha, not exactly. I had just forgot about the incoming 64 bits world at the time.

- Davide
Previous: Linus TorvaldsNext: Linus Torvalds
Message 18 of 33 in “heads-up: git-index-pack in "next" is broken”
  1. Junio C HamanoOct 17, 2006
  2. Nicolas PitreOct 17, 2006
  3. Junio C HamanoOct 17, 2006
  4. Nicolas PitreOct 17, 2006
  5. Junio C HamanoOct 17, 2006
  6. Nicolas PitreOct 17, 2006
  7. Sergey VlasovOct 17, 2006
  8. Junio C HamanoOct 17, 2006
  9. Nicolas PitreOct 17, 2006
  10. Nicolas PitreOct 17, 2006
  11. Linus TorvaldsOct 17, 2006
  12. Nicolas PitreOct 17, 2006
  13. Linus TorvaldsOct 17, 2006
  14. Nicolas PitreOct 18, 2006
  15. Linus TorvaldsOct 18, 2006
  16. Nicolas PitreOct 18, 2006
  17. Linus TorvaldsOct 18, 2006
  18. Davide LibenziOct 18, 2006
  19. Linus TorvaldsOct 18, 2006
  20. Davide LibenziOct 18, 2006
  21. Linus TorvaldsOct 18, 2006
  22. Davide LibenziOct 18, 2006
  23. Linus TorvaldsOct 18, 2006
  24. Davide LibenziOct 18, 2006
  25. Junio C HamanoOct 18, 2006
  26. Nicolas PitreOct 18, 2006
  27. Junio C HamanoOct 18, 2006
  28. Junio C HamanoOct 18, 2006
  29. Johannes SchindelinOct 18, 2006
  30. Nicolas PitreOct 18, 2006
  31. Nicolas PitreOct 18, 2006
  32. Junio C HamanoOct 17, 2006
  33. Nicolas PitreOct 18, 2006

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