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Re: [PATCH 3/3] revision: insert unsorted, then sort in prepare_revision_walk()

From
MFMartin Fick <mfick@codeaurora.org>
Date
Apr 2, 2012, 16:49 UTC
Message-ID
<201204021049.04901.mfick@codeaurora.org>
In-Reply-To
<CAJo=hJshOBg4pT8nuWZ=eZvj=E9x+4b9M_EANa=02x=NFW2OfQ@mail.gmail.com>
On Monday, April 02, 2012 10:39:59 am Shawn Pearce wrote:
> On Mon, Apr 2, 2012 at 09:24, Martin Fick 
<mfick@codeaurora.org> wrote:
> > On Saturday, March 31, 2012 04:11:01 pm René Scharfe 
wrote:
Show 6 quoted lines
> Git can't really do the same thing as "cache the
> RevWalk". Its spawning a new process that needs to
> decompress and parse each commit object to determine its
> timestamp so the commits can be sorted into the priority
> queue. This is still an O(N) operation given N
> references.

While I suspect this has been suggested before, an ondisk cache of commits to timestamps would probably help here with large repos. Such a cache could make even new processes able to create this list much quicker. Since this cache would contain immutable data, even if it is out of date it would likely provided significant improvements by providing most of the timestamps leaving only a few to parse from newer commits?

-Martin
-- 
Employee of Qualcomm Innovation Center, Inc. which is a 
member of Code Aurora Forum
Previous: Shawn PearceNext: Shawn Pearce
Message 19 of 37 in “Git push performance problems with ~100K refs”
  1. Martin FickMar 30, 2012
  2. Junio C HamanoMar 30, 2012
  3. Martin FickMar 30, 2012
  4. Jeff KingMar 30, 2012
  5. Jeff KingMar 30, 2012
  6. Martin FickMar 30, 2012
  7. 1/3 add mergesort() for linked listsRené Scharfe, Mar 31, 2012
  8. Junio C HamanoApr 5, 2012
  9. René ScharfeApr 8, 2012
  10. Junio C HamanoApr 9, 2012
  11. Stephen BoydApr 11, 2012
  12. Junio C HamanoApr 11, 2012
  13. 2/3 commit: use mergesort() in commit_list_sort_by_date()René Scharfe, Mar 31, 2012
  14. 3/3 revision: insert unsorted, then sort in prepare_revision_walk()René Scharfe, Mar 31, 2012
  15. Martin FickMar 31, 2012
  16. Junio C HamanoMar 31, 2012
  17. Martin FickApr 2, 2012
  18. Shawn PearceApr 2, 2012
  19. Martin FickApr 2, 2012
  20. Shawn PearceApr 2, 2012
  21. Jeff KingApr 2, 2012
  22. Jeff KingApr 2, 2012
  23. Martin FickApr 2, 2012
  24. Nguyen Thai Ngoc DuyApr 3, 2012
  25. Martin FickApr 3, 2012
  26. 0/3 Commit cacheNguyễn Thái Ngọc Duy, Apr 3, 2012
  27. 1/3 parse_commit_buffer: rename a confusing variable nameNguyễn Thái Ngọc Duy, Apr 3, 2012
  28. 2/3 Add commit cache to help speed up commit traversalNguyễn Thái Ngọc Duy, Apr 3, 2012
  29. 3/3 Add parse_commit_for_rev() to take advantage of sha1-cacheNguyễn Thái Ngọc Duy, Apr 3, 2012
  30. Nguyen Thai Ngoc DuyApr 5, 2012
  31. Shawn PearceApr 6, 2012
  32. Nguyen Thai Ngoc DuyApr 7, 2012
  33. Nguyen Thai Ngoc DuyApr 3, 2012
  34. Jeff KingApr 2, 2012
  35. René ScharfeApr 2, 2012
  36. Jeff KingApr 3, 2012
  37. Jeff KingApr 3, 2012

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