kernel/git - git - PowerEL Git System

Author	SHA1	Message	Date
Derrick Stolee	7b8a21dba1	commit-graph: lazy-load trees for commits The commit-graph file provides quick access to commit data, including the OID of the root tree for each commit in the graph. When performing a deep commit-graph walk, we may not need to load most of the trees for these commits. Delay loading the tree object for a commit loaded from the graph until requested via get_commit_tree(). Do not lazy-load trees for commits not in the graph, since that requires duplicate parsing and the relative peformance improvement when trees are not needed is small. On the Linux repository, performance tests were run for the following command: git log --graph --oneline -1000 Before: 0.92s After: 0.66s Rel %: -28.3% Adding '-- kernel/' to the command requires loading the root tree for every commit that is walked. There was no measureable performance change as a result of this patch. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	7 years ago
Derrick Stolee	2e27bd7731	treewide: replace maybe_tree with accessor methods In anticipation of making trees load lazily, create a Coccinelle script (contrib/coccinelle/commit.cocci) to ensure that all references to the 'maybe_tree' member of struct commit are either mutations or accesses through get_commit_tree() or get_commit_tree_oid(). Apply the Coccinelle script to create the rest of the patch. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	7 years ago
Derrick Stolee	891435d55d	treewide: rename tree to maybe_tree Using the commit-graph file to walk commit history removes the large cost of parsing commits during the walk. This exposes a performance issue: lookup_tree() takes a large portion of the computation time, even when Git never uses those trees. In anticipation of lazy-loading these trees, rename the 'tree' member of struct commit to 'maybe_tree'. This serves two purposes: it hints at the future role of possibly being NULL even if the commit has a valid tree, and it allows for unambiguous transformation from simple member access (i.e. commit->maybe_tree) to method access. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	7 years ago
Derrick Stolee	7547b95b4f	commit-graph: implement "--append" option Teach git-commit-graph to add all commits from the existing commit-graph file to the file about to be written. This should be used when adding new commits without performing garbage collection. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	7 years ago
Derrick Stolee	3d5df01b5e	commit-graph: build graph from starting commits Teach git-commit-graph to read commits from stdin when the --stdin-commits flag is specified. Commits reachable from these commits are added to the graph. This is a much faster way to construct the graph than inspecting all packed objects, but is restricted to known tips. For the Linux repository, 700,000+ commits were added to the graph file starting from 'master' in 7-9 seconds, depending on the number of packfiles in the repo (1, 24, or 120). Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	7 years ago
Derrick Stolee	049d51a2bb	commit-graph: read only from specific pack-indexes Teach git-commit-graph to inspect the objects only in a certain list of pack-indexes within the given pack directory. This allows updating the commit graph iteratively. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	7 years ago
Derrick Stolee	177722b344	commit: integrate commit graph with commit parsing Teach Git to inspect a commit graph file to supply the contents of a struct commit when calling parse_commit_gently(). This implementation satisfies all post-conditions on the struct commit, including loading parents, the root tree, and the commit date. If core.commitGraph is false, then do not check graph files. In test script t5318-commit-graph.sh, add output-matching conditions on read-only graph operations. By loading commits from the graph instead of parsing commit buffers, we save a lot of time on long commit walks. Here are some performance results for a copy of the Linux repository where 'master' has 678,653 reachable commits and is behind 'origin/master' by 59,929 commits. \| Command \| Before \| After \| Rel % \| \|----------------------------------\|--------\|--------\|-------\| \| log --oneline --topo-order -1000 \| 8.31s \| 0.94s \| -88% \| \| branch -vv \| 1.02s \| 0.14s \| -86% \| \| rev-list --all \| 5.89s \| 1.07s \| -81% \| \| rev-list --all --objects \| 66.15s \| 58.45s \| -11% \| Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	7 years ago
Derrick Stolee	4f2542b49e	commit-graph: close under reachability Teach write_commit_graph() to walk all parents from the commits discovered in packfiles. This prevents gaps given by loose objects or previously-missed packfiles. Also automatically add commits from the existing graph file, if it exists. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	7 years ago
Derrick Stolee	2a2e32bdc5	commit-graph: implement git commit-graph read Teach git-commit-graph to read commit graph files and summarize their contents. Use the read subcommand to verify the contents of a commit graph file in the tests. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	7 years ago
Derrick Stolee	08fd81c9b6	commit-graph: implement write_commit_graph() Teach Git to write a commit graph file by checking all packed objects to see if they are commits, then store the file in the given object directory. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	7 years ago