mirror of
https://github.com/git/git
synced 2024-10-30 14:03:28 +00:00
dc5d40f5bc
When running 'read-tree' with a single tree and no prefix,
'prime_cache_tree()' is called after the tree is unpacked. In that
situation, skip a redundant call to 'cache_tree_update()' in
'unpack_trees()' by enabling the 'skip_cache_tree_update' unpack option.
Removing the redundant cache tree update provides a substantial performance
improvement to 'git read-tree <tree-ish>', as shown by a test added to
'p0006-read-tree-checkout.sh':
Test before after
----------------------------------------------------------------------
read-tree br_ballast_plus_1 3.94(1.80+1.57) 3.00(1.14+1.28) -23.9%
Note that the 'read-tree' in 't1022-read-tree-partial-clone.sh' is updated
to read two trees, rather than one. The test was first introduced in
d3da223f22 (cache-tree: prefetch in partial clone read-tree, 2021-07-23) to
exercise the 'cache_tree_update()' code path, as used in 'git merge'. Since
this patch drops the call to 'cache_tree_update()' in single-tree 'git
read-tree', change the test to use the two-tree variant so that
'cache_tree_update()' is called as intended.
Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
75 lines
2.2 KiB
Bash
Executable file
75 lines
2.2 KiB
Bash
Executable file
#!/bin/sh
|
|
#
|
|
# This test measures the performance of various read-tree
|
|
# and checkout operations. It is primarily interested in
|
|
# the algorithmic costs of index operations and recursive
|
|
# tree traversal -- and NOT disk I/O on thousands of files.
|
|
|
|
test_description="Tests performance of read-tree"
|
|
|
|
. ./perf-lib.sh
|
|
|
|
test_perf_default_repo
|
|
|
|
# If the test repo was generated by ./repos/many-files.sh
|
|
# then we know something about the data shape and branches,
|
|
# so we can isolate testing to the ballast-related commits
|
|
# and setup sparse-checkout so we don't have to populate
|
|
# the ballast files and directories.
|
|
#
|
|
# Otherwise, we make some general assumptions about the
|
|
# repo and consider the entire history of the current
|
|
# branch to be the ballast.
|
|
|
|
test_expect_success "setup repo" '
|
|
if git rev-parse --verify refs/heads/p0006-ballast^{commit}
|
|
then
|
|
echo Assuming synthetic repo from many-files.sh &&
|
|
git branch br_base master &&
|
|
git branch br_ballast p0006-ballast^ &&
|
|
git branch br_ballast_alias p0006-ballast^ &&
|
|
git branch br_ballast_plus_1 p0006-ballast &&
|
|
git config --local core.sparsecheckout 1 &&
|
|
cat >.git/info/sparse-checkout <<-EOF
|
|
/*
|
|
!ballast/*
|
|
EOF
|
|
else
|
|
echo Assuming non-synthetic repo... &&
|
|
git branch br_base $(git rev-list HEAD | tail -n 1) &&
|
|
git branch br_ballast HEAD^ || error "no ancestor commit from current head" &&
|
|
git branch br_ballast_alias HEAD^ &&
|
|
git branch br_ballast_plus_1 HEAD
|
|
fi &&
|
|
git checkout -q br_ballast &&
|
|
nr_files=$(git ls-files | wc -l)
|
|
'
|
|
|
|
test_perf "read-tree br_base br_ballast ($nr_files)" '
|
|
git read-tree -n -m br_base br_ballast
|
|
'
|
|
|
|
test_perf "read-tree br_ballast_plus_1 ($nr_files)" '
|
|
# Run read-tree 100 times for clearer performance results & comparisons
|
|
for i in $(test_seq 100)
|
|
do
|
|
git read-tree -n -m br_ballast_plus_1 || return 1
|
|
done
|
|
'
|
|
|
|
test_perf "switch between br_base br_ballast ($nr_files)" '
|
|
git checkout -q br_base &&
|
|
git checkout -q br_ballast
|
|
'
|
|
|
|
test_perf "switch between br_ballast br_ballast_plus_1 ($nr_files)" '
|
|
git checkout -q br_ballast_plus_1 &&
|
|
git checkout -q br_ballast
|
|
'
|
|
|
|
test_perf "switch between aliases ($nr_files)" '
|
|
git checkout -q br_ballast_alias &&
|
|
git checkout -q br_ballast
|
|
'
|
|
|
|
test_done
|