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Re: [PATCH] write-tree performance problems

From
DWDavid Willmore <davidwillmore@gmail.com>
Date
Apr 20, 2005, 16:10 UTC
Message-ID
<1cddf4cc05042009101b151139@mail.gmail.com>
In-Reply-To
<Pine.LNX.4.58.0504200833580.6467@ppc970.osdl.org>
On 4/20/05, Linus Torvalds <torvalds@osdl.org> wrote:
> It really _shouldn't_ be faster. It still does the compression, and throws
> the end result away.

Am I misunderstanding or is the proglem that doing: <file with unknown status> -> compress -> sha1 -> compare with existing hash

is expensive?

What about doing: <file it's supposed to be equal to> -> uncompress -> compare with unknown status file

It's more file I/O, but the uncompress is much cheaper than the compress.

On a second issue, what's the format of the main 'index' file? Is it: <pathspec> <sha1hash> <pathspec> <sha1hash> ? If so, that's not going to compress well. A file like: <pathspec1> <pathspec2>

<sha1hash1> <sha1hash2>

Will compress better.

Stop me if I'm way off base--I'm just following the mailing list, I haven't tried out the code.

Cheers, David

Previous: Linus TorvaldsNext: Linus Torvalds
Message 33 of 54 in “write-tree performance problems”
  1. write-tree performance problemsChris Mason, Apr 19, 2005
  2. Linus TorvaldsApr 19, 2005
  3. Chris MasonApr 19, 2005
  4. Linus TorvaldsApr 19, 2005
  5. Chris MasonApr 19, 2005
  6. Linus TorvaldsApr 19, 2005
  7. Chris MasonApr 20, 2005
  8. Linus TorvaldsApr 20, 2005
  9. Linus TorvaldsApr 20, 2005
  10. H. Peter AnvinApr 20, 2005
  11. WARNING! Object DB conversion (was Re: [PATCH] write-tree performance problems)Linus Torvalds, Apr 20, 2005
  12. Ingo MolnarApr 20, 2005
  13. Jon SeymourApr 20, 2005
  14. Martin UeckerApr 20, 2005
  15. Morten WelinderApr 20, 2005
  16. Jon SeymourApr 20, 2005
  17. C. Scott AnanianApr 20, 2005
  18. Martin UeckerApr 20, 2005
  19. C. Scott AnanianApr 20, 2005
  20. Martin UeckerApr 20, 2005
  21. Martin UeckerApr 20, 2005
  22. Blob chunking code. [First look.]C. Scott Ananian, Apr 20, 2005
  23. Blob chunking code. [Second look]C. Scott Ananian, Apr 20, 2005
  24. David WoodhouseApr 20, 2005
  25. Linus TorvaldsApr 20, 2005
  26. David WoodhouseApr 20, 2005
  27. Chris MasonApr 20, 2005
  28. C. Scott AnanianApr 20, 2005
  29. Linus TorvaldsApr 20, 2005
  30. C. Scott AnanianApr 20, 2005
  31. Linus TorvaldsApr 20, 2005
  32. Linus TorvaldsApr 20, 2005
  33. David WillmoreApr 20, 2005
  34. Linus TorvaldsApr 20, 2005
  35. Linus TorvaldsApr 20, 2005
  36. Chris MasonApr 20, 2005
  37. Linus TorvaldsApr 20, 2005
  38. Chris MasonApr 20, 2005
  39. Linus TorvaldsApr 20, 2005
  40. Chris MasonApr 20, 2005
  41. Linus TorvaldsApr 20, 2005
  42. Linus TorvaldsApr 20, 2005
  43. David S. MillerApr 20, 2005
  44. David LangApr 19, 2005
  45. Linus TorvaldsApr 19, 2005
  46. David LangApr 19, 2005
  47. Linus TorvaldsApr 19, 2005
  48. David LangApr 19, 2005
  49. Linus TorvaldsApr 19, 2005
  50. Christopher LiApr 19, 2005
  51. Olivier GalibertApr 19, 2005
  52. C. Scott AnanianApr 19, 2005
  53. Linus TorvaldsApr 20, 2005
  54. C. Scott AnanianApr 20, 2005

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