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author | Derrick Stolee <dstolee@microsoft.com> | 2019-11-21 22:04:41 +0000 |
---|---|---|
committer | Junio C Hamano <gitster@pobox.com> | 2019-11-22 16:11:44 +0900 |
commit | 96cc8ab5318cd57c8bc203b8f064b35883b2386f (patch) | |
tree | 34c7c46a9525f853ba710fe070fd191060ac2cdd /unpack-trees.c | |
parent | sparse-checkout: add 'cone' mode (diff) | |
download | tgif-96cc8ab5318cd57c8bc203b8f064b35883b2386f.tar.xz |
sparse-checkout: use hashmaps for cone patterns
The parent and recursive patterns allowed by the "cone mode"
option in sparse-checkout are restrictive enough that we
can avoid using the regex parsing. Everything is based on
prefix matches, so we can use hashsets to store the prefixes
from the sparse-checkout file. When checking a path, we can
strip path entries from the path and check the hashset for
an exact match.
As a test, I created a cone-mode sparse-checkout file for the
Linux repository that actually includes every file. This was
constructed by taking every folder in the Linux repo and creating
the pattern pairs here:
/$folder/
!/$folder/*/
This resulted in a sparse-checkout file sith 8,296 patterns.
Running 'git read-tree -mu HEAD' on this file had the following
performance:
core.sparseCheckout=false: 0.21 s (0.00 s)
core.sparseCheckout=true: 3.75 s (3.50 s)
core.sparseCheckoutCone=true: 0.23 s (0.01 s)
The times in parentheses above correspond to the time spent
in the first clear_ce_flags() call, according to the trace2
performance traces.
While this example is contrived, it demonstrates how these
patterns can slow the sparse-checkout feature.
Helped-by: Eric Wong <e@80x24.org>
Helped-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'unpack-trees.c')
-rw-r--r-- | unpack-trees.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/unpack-trees.c b/unpack-trees.c index 01a05ff66d..a90d71845d 100644 --- a/unpack-trees.c +++ b/unpack-trees.c @@ -1482,6 +1482,7 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options o->skip_sparse_checkout = 1; if (!o->skip_sparse_checkout) { char *sparse = git_pathdup("info/sparse-checkout"); + pl.use_cone_patterns = core_sparse_checkout_cone; if (add_patterns_from_file_to_list(sparse, "", 0, &pl, NULL) < 0) o->skip_sparse_checkout = 1; else |