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Re: [PATCH v2 6/9] index-format: update preamble to cached tree extension

From
Junio C Hamano <gitster@pobox.com>
Date
Jan 7, 2021, 20:12 UTC
Message-ID
<xmqqv9c8ld5h.fsf@gitster.c.googlers.com>
In-Reply-To
<5a1a51c1-7ada-6f66-a6d0-2fc01303d334@gmail.com>
Derrick Stolee <stolee@gmail.com> writes:
Show 8 quoted lines
>> We later found out that we rather often compare the index against
>> the tree of HEAD (think: "git status"), and diff-lib.c::diff_cache()
>> does take advantage of the fact that an entire directory can be
>> skipped if the tree object taken from the HEAD side exactly matches
>> the tree recorded for the subdirectory in the cache tree extension.
>
> I need to read more about this. traverse_by_cache_tree() seems to
> be a good place to start. Thanks.
Ah, that one I forgot about.

What I had in mind was a different optimization that is far more aggressive in unpack-trees.c::unpack_callback(); look for a comment that begins with "Everything under the name matches". The block allows us to skip an entire subdirectory hierarchy.

Previous: Derrick StoleeNext: Junio C Hamano
Message 37 of 53 in “Cleanups around index operations”
  1. 0/8 Cleanups around index operationsDerrick Stolee via GitGitGadget, Dec 30, 2020
  2. 1/8 tree-walk: report recursion countsDerrick Stolee via GitGitGadget, Dec 30, 2020
  3. Elijah NewrenDec 30, 2020
  4. Derrick StoleeDec 30, 2020
  5. 3/8 cache-tree: use trace2 in cache_tree_update()Derrick Stolee via GitGitGadget, Dec 30, 2020
  6. 2/8 unpack-trees: add trace2 regionsDerrick Stolee via GitGitGadget, Dec 30, 2020
  7. Elijah NewrenDec 30, 2020
  8. 4/8 cache-tree: trace regions for I/ODerrick Stolee via GitGitGadget, Dec 30, 2020
  9. 6/8 index-format: update preamble to cached tree extensionDerrick Stolee via GitGitGadget, Dec 30, 2020
  10. Elijah NewrenDec 30, 2020
  11. 8/8 cache-tree: avoid path comparison loop when silentDerrick Stolee via GitGitGadget, Dec 30, 2020
  12. Elijah NewrenDec 30, 2020
  13. Junio C HamanoJan 6, 2021
  14. Derrick StoleeJan 6, 2021
  15. René ScharfeDec 31, 2020
  16. Derrick StoleeDec 31, 2020
  17. René ScharfeJan 1, 2021
  18. cache-tree: use ce_namelen() instead of strlen()René Scharfe, Jan 2, 2021
  19. Derrick StoleeJan 4, 2021
  20. Junio C HamanoJan 5, 2021
  21. René ScharfeJan 2, 2021
  22. 5/8 cache-tree: trace regions for prime_cache_treeDerrick Stolee via GitGitGadget, Dec 30, 2020
  23. Elijah NewrenDec 30, 2020
  24. Derrick StoleeDec 30, 2020
  25. 7/8 index-format: discuss recursion of cached-tree betterDerrick Stolee via GitGitGadget, Dec 30, 2020
  26. Elijah NewrenDec 30, 2020
  27. Derrick StoleeDec 30, 2020
  28. 0/9 Cleanups around index operationsDerrick Stolee via GitGitGadget, Jan 4, 2021
  29. 2/9 unpack-trees: add trace2 regionsDerrick Stolee via GitGitGadget, Jan 4, 2021
  30. 4/9 cache-tree: trace regions for I/ODerrick Stolee via GitGitGadget, Jan 4, 2021
  31. 1/9 tree-walk: report recursion countsDerrick Stolee via GitGitGadget, Jan 4, 2021
  32. 3/9 cache-tree: use trace2 in cache_tree_update()Derrick Stolee via GitGitGadget, Jan 4, 2021
  33. 5/9 cache-tree: trace regions for prime_cache_treeDerrick Stolee via GitGitGadget, Jan 4, 2021
  34. 6/9 index-format: update preamble to cached tree extensionDerrick Stolee via GitGitGadget, Jan 4, 2021
  35. Junio C HamanoJan 7, 2021
  36. Derrick StoleeJan 7, 2021
  37. Junio C HamanoJan 7, 2021
  38. Junio C HamanoJan 7, 2021
  39. 7/9 index-format: discuss recursion of cached-tree betterDerrick Stolee via GitGitGadget, Jan 4, 2021
  40. 9/9 cache-tree: speed up consecutive path comparisonsDerrick Stolee via GitGitGadget, Jan 4, 2021
  41. 8/9 cache-tree: use ce_namelen() instead of strlen()René Scharfe via GitGitGadget, Jan 4, 2021
  42. 00/10 Cleanups around index operationsDerrick Stolee via GitGitGadget, Jan 7, 2021
  43. 01/10 tree-walk: report recursion countsDerrick Stolee via GitGitGadget, Jan 7, 2021
  44. 02/10 unpack-trees: add trace2 regionsDerrick Stolee via GitGitGadget, Jan 7, 2021
  45. 03/10 cache-tree: use trace2 in cache_tree_update()Derrick Stolee via GitGitGadget, Jan 7, 2021
  46. 04/10 cache-tree: trace regions for I/ODerrick Stolee via GitGitGadget, Jan 7, 2021
  47. 06/10 index-format: use 'cache tree' over 'cached tree'Derrick Stolee via GitGitGadget, Jan 7, 2021
  48. 08/10 index-format: discuss recursion of cached-tree betterDerrick Stolee via GitGitGadget, Jan 7, 2021
  49. 09/10 cache-tree: use ce_namelen() instead of strlen()René Scharfe via GitGitGadget, Jan 7, 2021
  50. 10/10 cache-tree: speed up consecutive path comparisonsDerrick Stolee via GitGitGadget, Jan 7, 2021
  51. 05/10 cache-tree: trace regions for prime_cache_treeDerrick Stolee via GitGitGadget, Jan 7, 2021
  52. 07/10 index-format: update preamble to cache tree extensionDerrick Stolee via GitGitGadget, Jan 7, 2021
  53. Junio C HamanoJan 16, 2021

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