All of lore.kernel.org
 help / color / mirror / Atom feed
* [PATCH 0/7] Sparse index: integrate with 'git stash'
@ 2022-04-25 17:49 Victoria Dye via GitGitGadget
  2022-04-25 17:49 ` [PATCH 1/7] stash: expand sparse-checkout compatibility testing Victoria Dye via GitGitGadget
                   ` (8 more replies)
  0 siblings, 9 replies; 42+ messages in thread
From: Victoria Dye via GitGitGadget @ 2022-04-25 17:49 UTC (permalink / raw)
  To: git; +Cc: derrickstolee, newren, gitster, Victoria Dye

This series, in combination with the sparse index integrations of reset [1],
update-index [2], checkout-index [2], clean [2], and read-tree [3], allows
most subcommands of 'git stash' to use the sparse index end-to-end without
index expansion.

Like the earlier series, this series starts with new tests ensuring
compatibility of the sparse index with non-sparse index full and sparse
checkouts [1/7]. Next, sparse index is trivially enabled [2/7].
Functionally, sparse index-enabled sparse-checkouts remain compatible with
non-sparse index sparse-checkouts, but there are still some cases where the
index (or a temporary index) is expanded unnecessarily. These cases are
fixed in three parts:

 * First, 'git stash -u' is made sparse index-compatible by ensuring the
   "temporary" index holding the stashed, untracked files is created as a
   sparse index whenever possible (per repo settings &
   'is_sparse_index_allowed()'). Patch [3/7] exposes
   'is_sparse_index_allowed()' to files outside of 'sparse-index.c', then
   patch [4/7] uses that function to mark the temporary index sparse when
   appropriate.
 * Next, 'git stash (apply|pop)' are made sparse index-compatible by
   changing their internal "merge" function (executed via
   'merge_recursive_generic()') from 'merge_recursive()' to
   'merge_ort_recursive()'. This requires first allowing
   'merge_recursive_generic()' to accept a merge function as an input
   (rather than hardcoding use of 'merge_recursive()') in patch [5/7], then
   changing the call in 'stash.c' to specify 'merge_ort_recursive()' in
   patch [6/7]. See note [4] for possible alternate implementations.
 * Finally, while patches 5 & 6 avoid index expansion for most cases of 'git
   stash (apply|pop)', applying a stash that includes untracked files still
   expands the index. This is a result of an internal 'read-tree' execution
   (specifically in its 'unpack_trees' call) creating a result index that is
   never sparse in-core, thus forcing the index to be unnecessarily
   collapsed and re-expanded in 'do_write_locked_index()'. In patch [7/7],
   'unpack_trees' is updated to set the default sparsity of the resultant
   index to "sparse" if allowed by repo settings and
   'is_sparse_index_allowed()' (similar to the change in patch 4).

Performance results (from the 'p2000' tests):

(git stash &&
 git stash pop)              master            this series
---------------------------------------------------------------------
full-v3                      4.07(2.42+1.34)   3.98(2.42+1.32) -2.2%
full-v4                      4.05(2.46+1.31)   4.00(2.49+1.29) -1.2%
sparse-v3                    7.48(4.81+2.57)   1.53(0.26+1.61) -79.5%
sparse-v4                    7.35(4.74+2.54)   1.59(0.27+1.63) -78.4%

(echo >>new &&
 git stash -u &&
 git stash pop)              master            this series
---------------------------------------------------------------------
full-v3                      4.21(2.62+1.45)   4.11(2.55+1.44) -2.4%
full-v4                      4.11(2.51+1.41)   4.02(2.49+1.41) -2.2%
sparse-v3                    7.35(4.64+2.66)   1.70(0.32+1.64) -76.9%
sparse-v4                    7.74(4.87+2.83)   1.70(0.32+1.66) -78.0%


[1]
https://lore.kernel.org/git/pull.1048.v6.git.1638201164.gitgitgadget@gmail.com/
[2]
https://lore.kernel.org/git/pull.1109.v2.git.1641924306.gitgitgadget@gmail.com/
[3]
https://lore.kernel.org/git/pull.1157.v3.git.1646166271.gitgitgadget@gmail.com/
[4] I went with changing 'stash' to always use 'merge-ort' in
'merge_recursive_generic()' as a sort of "middle ground" between "replace
'merge_recursive()' with 'merge_ort_recursive()' in all of its hardcoded
internal usage" and "only use 'merge-ort' if using a sparse index in 'git
stash', otherwise 'merge-recursive'". The former would extend the use of
'merge-ort' to 'git am' and 'git merge-recursive', whereas the latter is a
more cautious/narrowly-focused option. If anyone has any other thoughts, I'm
interested in hearing them.

Thanks!

-Victoria

Victoria Dye (7):
  stash: expand sparse-checkout compatibility testing
  stash: integrate with sparse index
  sparse-index: expose 'is_sparse_index_allowed()'
  read-cache: set sparsity when index is new
  merge-recursive: add merge function arg to 'merge_recursive_generic'
  stash: merge applied stash with merge-ort
  unpack-trees: preserve index sparsity

 builtin/am.c                             |  2 +-
 builtin/merge-recursive.c                |  2 +-
 builtin/stash.c                          |  6 +-
 merge-ort.c                              |  3 +-
 merge-recursive.c                        |  4 +-
 merge-recursive.h                        |  9 ++-
 read-cache.c                             | 18 ++++-
 sparse-index.c                           |  2 +-
 sparse-index.h                           |  1 +
 t/perf/p2000-sparse-operations.sh        |  2 +
 t/t1092-sparse-checkout-compatibility.sh | 94 +++++++++++++++++++++---
 unpack-trees.c                           |  6 ++
 12 files changed, 131 insertions(+), 18 deletions(-)


base-commit: 6cd33dceed60949e2dbc32e3f0f5e67c4c882e1e
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1171%2Fvdye%2Fsparse%2Fstash-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1171/vdye/sparse/stash-v1
Pull-Request: https://github.com/gitgitgadget/git/pull/1171
-- 
gitgitgadget

^ permalink raw reply	[flat|nested] 42+ messages in thread

end of thread, other threads:[~2022-05-12 16:56 UTC | newest]

Thread overview: 42+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-04-25 17:49 [PATCH 0/7] Sparse index: integrate with 'git stash' Victoria Dye via GitGitGadget
2022-04-25 17:49 ` [PATCH 1/7] stash: expand sparse-checkout compatibility testing Victoria Dye via GitGitGadget
2022-04-25 17:49 ` [PATCH 2/7] stash: integrate with sparse index Victoria Dye via GitGitGadget
2022-04-25 21:34   ` Junio C Hamano
2022-04-26 12:53   ` Derrick Stolee
2022-04-26 15:26     ` Victoria Dye
2022-04-26 16:21     ` Junio C Hamano
2022-04-25 17:49 ` [PATCH 3/7] sparse-index: expose 'is_sparse_index_allowed()' Victoria Dye via GitGitGadget
2022-04-25 17:49 ` [PATCH 4/7] read-cache: set sparsity when index is new Victoria Dye via GitGitGadget
2022-04-25 21:35   ` Junio C Hamano
2022-04-25 17:49 ` [PATCH 5/7] merge-recursive: add merge function arg to 'merge_recursive_generic' Victoria Dye via GitGitGadget
2022-04-25 21:38   ` Junio C Hamano
2022-04-26 12:57     ` Derrick Stolee
2022-04-25 17:49 ` [PATCH 6/7] stash: merge applied stash with merge-ort Victoria Dye via GitGitGadget
2022-04-26 13:02   ` Derrick Stolee
2022-04-25 17:49 ` [PATCH 7/7] unpack-trees: preserve index sparsity Victoria Dye via GitGitGadget
2022-04-26 12:49 ` [PATCH 0/7] Sparse index: integrate with 'git stash' Derrick Stolee
2022-04-26 13:09   ` Derrick Stolee
2022-04-27 18:16 ` [PATCH v2 " Victoria Dye via GitGitGadget
2022-04-27 18:16   ` [PATCH v2 1/7] stash: expand sparse-checkout compatibility testing Victoria Dye via GitGitGadget
2022-04-27 18:16   ` [PATCH v2 2/7] stash: integrate with sparse index Victoria Dye via GitGitGadget
2022-04-27 18:16   ` [PATCH v2 3/7] sparse-index: expose 'is_sparse_index_allowed()' Victoria Dye via GitGitGadget
2022-04-27 18:16   ` [PATCH v2 4/7] read-cache: set sparsity when index is new Victoria Dye via GitGitGadget
2022-04-27 18:16   ` [PATCH v2 5/7] merge-recursive: add merge function arg to 'merge_recursive_generic' Victoria Dye via GitGitGadget
2022-05-06  7:23     ` Elijah Newren
2022-05-09 19:24       ` Victoria Dye
2022-05-10  7:06         ` Elijah Newren
2022-04-27 18:16   ` [PATCH v2 6/7] stash: merge applied stash with merge-ort Victoria Dye via GitGitGadget
2022-04-27 18:16   ` [PATCH v2 7/7] unpack-trees: preserve index sparsity Victoria Dye via GitGitGadget
2022-05-06  7:46   ` [PATCH v2 0/7] Sparse index: integrate with 'git stash' Elijah Newren
2022-05-10 23:32   ` [PATCH v3 0/6] " Victoria Dye via GitGitGadget
2022-05-10 23:32     ` [PATCH v3 1/6] stash: expand sparse-checkout compatibility testing Victoria Dye via GitGitGadget
2022-05-10 23:32     ` [PATCH v3 2/6] stash: integrate with sparse index Victoria Dye via GitGitGadget
2022-05-10 23:32     ` [PATCH v3 3/6] sparse-index: expose 'is_sparse_index_allowed()' Victoria Dye via GitGitGadget
2022-05-10 23:32     ` [PATCH v3 4/6] read-cache: set sparsity when index is new Victoria Dye via GitGitGadget
2022-05-10 23:32     ` [PATCH v3 5/6] stash: apply stash using 'merge_ort_nonrecursive()' Victoria Dye via GitGitGadget
2022-05-11  0:26       ` Junio C Hamano
2022-05-12  1:01       ` Jonathan Tan
2022-05-12 14:52         ` Elijah Newren
2022-05-12 16:55           ` Jonathan Tan
2022-05-12 14:51       ` Elijah Newren
2022-05-10 23:32     ` [PATCH v3 6/6] unpack-trees: preserve index sparsity Victoria Dye via GitGitGadget

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.