This patch series performs a decently-sized refactoring of the revision-walk machinery. Well, "refactoring" is probably the wrong word, as I don't actually remove the old code. Instead, when we see certain options in the 'rev_info' struct, we redirect the commit-walk logic to a new set of methods that distribute the workload differently. By using generation numbers in the commit-graph, we can significantly improve 'git log --graph' commands (and the underlying 'git rev-list --topo-order'). On the Linux repository, I got the following performance results when comparing to the previous version with or without a commit-graph: Test: git rev-list --topo-order -100 HEAD HEAD~1, no commit-graph: 6.80 s HEAD~1, w/ commit-graph: 0.77 s HEAD, w/ commit-graph: 0.02 s Test: git rev-list --topo-order -100 HEAD -- tools HEAD~1, no commit-graph: 9.63 s HEAD~1, w/ commit-graph: 6.06 s HEAD, w/ commit-graph: 0.06 s If you want to read this series but are unfamiliar with the commit-graph and generation numbers, then I recommend reading Documentation/technical/commit-graph.txt or a blob post [1] I wrote on the subject. In particular, the three-part walk described in "revision.c: refactor basic topo-order logic" is present (but underexplained) as an animated PNG [2]. Since revision.c is an incredibly important (and old) portion of the codebase -- and because there are so many orthogonal options in 'struct rev_info' -- I consider this submission to be "RFC quality". That is, I am not confident that I am not missing anything, or that my solution is the best it can be. I did merge this branch with ds/commit-graph-with-grafts and the "DO-NOT-MERGE: write and read commit-graph always" commit that computes a commit-graph with every 'git commit' command. The test suite passed with that change, available on GitHub [3]. To ensure that I cover at least the case I think are interesting, I added tests to t6600-test-reach.sh to verify the walks report the correct results for the three cases there (no commit-graph, full commit-graph, and a partial commit-graph so the walk starts at GENERATION_NUMBER_INFINITY). One notable case that is not included in this series is the case of a history comparison such as 'git rev-list --topo-order A..B'. The existing code in limit_list() has ways to cut the walk short when all pending commits are UNINTERESTING. Since this code depends on commit_list instead of the prio_queue we are using here, I chose to leave it untouched for now. We can revisit it in a separate series later. Since handle_commit() turns on revs->limited when a commit is UNINTERESTING, we do not hit the new code in this case. Removing this 'revs->limited = 1;' line yields correct results, but the performance is worse. This series was based on ds/reachable, but is now based on 'master' to not conflict with 182070 "commit: use timestamp_t for author_date_slab". There is a small conflict with md/filter-trees, because it renamed a flag in revisions.h in the line before I add new flags. Hopefully this conflict is not too difficult to resolve. Changes in V3: I added a new patch that updates the tab-alignment for flags in revision.h before adding new ones (Thanks, Ævar!). Also, I squashed the recommended changes to run_three_modes and test_three_modes from Szeder and Junio. Thanks! Thanks, -Stolee [1] https://blogs.msdn.microsoft.com/devops/2018/07/09/supercharging-the-git-commit-graph-iii-generations/ Supercharging the Git Commit Graph III: Generations and Graph Algorithms [2] https://msdnshared.blob.core.windows.net/media/2018/06/commit-graph-topo-order-b-a.png Animation showing three-part walk [3] https://github.com/derrickstolee/git/tree/topo-order/testA branch containing this series along with commits to compute commit-graph in entire test suite. Cc: avarab@gmail.comCc: szeder.dev@xxxxxxxxx Derrick Stolee (7): prio-queue: add 'peek' operation test-reach: add run_three_modes method test-reach: add rev-list tests revision.c: begin refactoring --topo-order logic commit/revisions: bookkeeping before refactoring revision.h: add whitespace in flag definitions revision.c: refactor basic topo-order logic commit.c | 11 +- commit.h | 8 ++ object.h | 4 +- prio-queue.c | 9 ++ prio-queue.h | 6 + revision.c | 232 ++++++++++++++++++++++++++++++++++++- revision.h | 34 +++--- t/helper/test-prio-queue.c | 10 +- t/t6600-test-reach.sh | 96 ++++++++++++++- 9 files changed, 374 insertions(+), 36 deletions(-) base-commit: 2d3b1c576c85b7f5db1f418907af00ab88e0c303 Published-As: https://github.com/gitgitgadget/git/releases/tags/pr-25%2Fderrickstolee%2Ftopo-order%2Fprogress-v3 Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-25/derrickstolee/topo-order/progress-v3 Pull-Request: https://github.com/gitgitgadget/git/pull/25 Range-diff vs v2: 1: cc1ec4c270 = 1: cc1ec4c270 prio-queue: add 'peek' operation 2: 404c918608 ! 2: b2a1ade148 test-reach: add run_three_modes method @@ -11,10 +11,6 @@ run_three_modes method that executes the given command and tests the actual output to the expected output. - While inspecting this code, I realized that the final test for - 'commit_contains --tag' is silently dropping the '--tag' argument. - It should be quoted to include both. - Signed-off-by: Derrick Stolee <dstolee@xxxxxxxxxxxxx> diff --git a/t/t6600-test-reach.sh b/t/t6600-test-reach.sh @@ -28,31 +24,22 @@ +run_three_modes () { test_when_finished rm -rf .git/objects/info/commit-graph && - test-tool reach $1 <input >actual && -+ $1 <input >actual && ++ "$@" <input >actual && test_cmp expect actual && cp commit-graph-full .git/objects/info/commit-graph && - test-tool reach $1 <input >actual && -+ $1 <input >actual && ++ "$@" <input >actual && test_cmp expect actual && cp commit-graph-half .git/objects/info/commit-graph && - test-tool reach $1 <input >actual && -+ $1 <input >actual && ++ "$@" <input >actual && test_cmp expect actual } +test_three_modes () { -+ run_three_modes "test-tool reach $1" ++ run_three_modes test-tool reach "$@" +} + test_expect_success 'ref_newer:miss' ' cat >input <<-\EOF && A:commit-5-7 -@@ - EOF - echo "commit_contains(_,A,X,_):1" >expect && - test_three_modes commit_contains && -- test_three_modes commit_contains --tag -+ test_three_modes "commit_contains --tag" - ' - - test_expect_success 'commit_contains:miss' ' 3: 30dee58c61 ! 3: b0ceb96076 test-reach: add rev-list tests @@ -30,7 +30,7 @@ + commit-6-2 commit-5-2 commit-4-2 commit-3-2 commit-2-2 commit-1-2 \ + commit-6-1 commit-5-1 commit-4-1 commit-3-1 commit-2-1 commit-1-1 \ + >expect && -+ run_three_modes "git rev-list --topo-order commit-6-6" ++ run_three_modes git rev-list --topo-order commit-6-6 +' + +test_expect_success 'rev-list: first-parent topo-order' ' @@ -42,7 +42,7 @@ + commit-6-2 \ + commit-6-1 commit-5-1 commit-4-1 commit-3-1 commit-2-1 commit-1-1 \ + >expect && -+ run_three_modes "git rev-list --first-parent --topo-order commit-6-6" ++ run_three_modes git rev-list --first-parent --topo-order commit-6-6 +' + +test_expect_success 'rev-list: range topo-order' ' @@ -54,7 +54,7 @@ + commit-6-2 commit-5-2 commit-4-2 \ + commit-6-1 commit-5-1 commit-4-1 \ + >expect && -+ run_three_modes "git rev-list --topo-order commit-3-3..commit-6-6" ++ run_three_modes git rev-list --topo-order commit-3-3..commit-6-6 +' + +test_expect_success 'rev-list: range topo-order' ' @@ -66,7 +66,7 @@ + commit-6-2 commit-5-2 commit-4-2 \ + commit-6-1 commit-5-1 commit-4-1 \ + >expect && -+ run_three_modes "git rev-list --topo-order commit-3-8..commit-6-6" ++ run_three_modes git rev-list --topo-order commit-3-8..commit-6-6 +' + +test_expect_success 'rev-list: first-parent range topo-order' ' @@ -78,7 +78,7 @@ + commit-6-2 \ + commit-6-1 commit-5-1 commit-4-1 \ + >expect && -+ run_three_modes "git rev-list --first-parent --topo-order commit-3-8..commit-6-6" ++ run_three_modes git rev-list --first-parent --topo-order commit-3-8..commit-6-6 +' + +test_expect_success 'rev-list: ancestry-path topo-order' ' @@ -88,7 +88,7 @@ + commit-6-4 commit-5-4 commit-4-4 commit-3-4 \ + commit-6-3 commit-5-3 commit-4-3 \ + >expect && -+ run_three_modes "git rev-list --topo-order --ancestry-path commit-3-3..commit-6-6" ++ run_three_modes git rev-list --topo-order --ancestry-path commit-3-3..commit-6-6 +' + +test_expect_success 'rev-list: symmetric difference topo-order' ' @@ -102,7 +102,7 @@ + commit-3-8 commit-2-8 commit-1-8 \ + commit-3-7 commit-2-7 commit-1-7 \ + >expect && -+ run_three_modes "git rev-list --topo-order commit-3-8...commit-6-6" ++ run_three_modes git rev-list --topo-order commit-3-8...commit-6-6 +' + test_done 4: a74ae13d4e = 4: fd1a0ab7cd revision.c: begin refactoring --topo-order logic 5: 0e64fc144c = 5: e86f304082 commit/revisions: bookkeeping before refactoring -: ---------- > 6: fa6d5ef152 revision.h: add whitespace in flag definitions 6: 3b185ac3b1 ! 7: 020b2f50c5 revision.c: refactor basic topo-order logic @@ -404,11 +404,11 @@ --- a/revision.h +++ b/revision.h @@ - #define USER_GIVEN (1u<<25) /* given directly by the user */ - #define TRACK_LINEAR (1u<<26) - #define ALL_REV_FLAGS (((1u<<11)-1) | USER_GIVEN | TRACK_LINEAR) -+#define TOPO_WALK_EXPLORED (1u<<27) -+#define TOPO_WALK_INDEGREE (1u<<28) + #define USER_GIVEN (1u<<25) /* given directly by the user */ + #define TRACK_LINEAR (1u<<26) + #define ALL_REV_FLAGS (((1u<<11)-1) | USER_GIVEN | TRACK_LINEAR) ++#define TOPO_WALK_EXPLORED (1u<<27) ++#define TOPO_WALK_INDEGREE (1u<<28) #define DECORATE_SHORT_REFS 1 #define DECORATE_FULL_REFS 2 -- gitgitgadget
