From: "Derrick Stolee via GitGitGadget" <gitgitgadget@gmail.com>
To: git@vger.kernel.org
Cc: Junio C Hamano <gitster@pobox.com>
Subject: [PATCH 0/6] Use generation numbers for --topo-order
Date: Mon, 27 Aug 2018 13:41:21 -0700 (PDT) [thread overview]
Message-ID: <pull.25.git.gitgitgadget@gmail.com> (raw)
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 is based on ds/reachable.
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.
Derrick Stolee (6):
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.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 | 6 +
t/helper/test-prio-queue.c | 10 +-
t/t6600-test-reach.sh | 98 +++++++++++++++-
9 files changed, 361 insertions(+), 23 deletions(-)
base-commit: 6cc017431c1c48f80d1c6512fdcc9866cf4b7f55
Published-As: https://github.com/gitgitgadget/git/releases/tags/pr-25%2Fderrickstolee%2Ftopo-order%2Fprogress-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-25/derrickstolee/topo-order/progress-v1
Pull-Request: https://github.com/gitgitgadget/git/pull/25
--
gitgitgadget
next reply other threads:[~2018-08-27 20:41 UTC|newest]
Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-27 20:41 Derrick Stolee via GitGitGadget [this message]
2018-08-27 20:41 ` [PATCH 1/6] prio-queue: add 'peek' operation Derrick Stolee via GitGitGadget
2018-08-27 20:41 ` [PATCH 2/6] test-reach: add run_three_modes method Derrick Stolee via GitGitGadget
2018-08-27 20:41 ` [PATCH 3/6] test-reach: add rev-list tests Derrick Stolee via GitGitGadget
2018-08-27 20:41 ` [PATCH 4/6] revision.c: begin refactoring --topo-order logic Derrick Stolee via GitGitGadget
2018-08-27 20:41 ` [PATCH 5/6] commit/revisions: bookkeeping before refactoring Derrick Stolee via GitGitGadget
2018-08-27 20:41 ` [PATCH 6/6] revision.c: refactor basic topo-order logic Derrick Stolee via GitGitGadget
2018-08-27 21:23 ` [PATCH 0/6] Use generation numbers for --topo-order Junio C Hamano
2018-09-18 4:08 ` [PATCH v2 " Derrick Stolee via GitGitGadget
2018-09-18 4:08 ` [PATCH v2 1/6] prio-queue: add 'peek' operation Derrick Stolee via GitGitGadget
2018-09-18 4:08 ` [PATCH v2 2/6] test-reach: add run_three_modes method Derrick Stolee via GitGitGadget
2018-09-18 18:02 ` SZEDER Gábor
2018-09-19 19:31 ` Junio C Hamano
2018-09-19 19:38 ` Junio C Hamano
2018-09-20 21:18 ` Junio C Hamano
2018-09-18 4:08 ` [PATCH v2 3/6] test-reach: add rev-list tests Derrick Stolee via GitGitGadget
2018-09-18 4:08 ` [PATCH v2 4/6] revision.c: begin refactoring --topo-order logic Derrick Stolee via GitGitGadget
2018-09-18 4:08 ` [PATCH v2 5/6] commit/revisions: bookkeeping before refactoring Derrick Stolee via GitGitGadget
2018-09-18 4:08 ` [PATCH v2 6/6] revision.c: refactor basic topo-order logic Derrick Stolee via GitGitGadget
2018-09-18 5:51 ` Ævar Arnfjörð Bjarmason
2018-09-18 6:05 ` [PATCH v2 0/6] Use generation numbers for --topo-order Ævar Arnfjörð Bjarmason
2018-09-21 15:47 ` Derrick Stolee
2018-09-21 17:39 ` [PATCH v3 0/7] " Derrick Stolee via GitGitGadget
2018-09-21 17:39 ` [PATCH v3 1/7] prio-queue: add 'peek' operation Derrick Stolee via GitGitGadget
2018-09-26 19:15 ` Derrick Stolee
2018-10-11 13:54 ` Jeff King
2018-09-21 17:39 ` [PATCH v3 2/7] test-reach: add run_three_modes method Derrick Stolee via GitGitGadget
2018-10-11 13:57 ` Jeff King
2018-09-21 17:39 ` [PATCH v3 3/7] test-reach: add rev-list tests Derrick Stolee via GitGitGadget
2018-10-11 13:58 ` Jeff King
2018-10-12 4:34 ` Junio C Hamano
2018-09-21 17:39 ` [PATCH v3 4/7] revision.c: begin refactoring --topo-order logic Derrick Stolee via GitGitGadget
2018-10-11 14:06 ` Jeff King
2018-10-12 6:33 ` Junio C Hamano
2018-10-12 12:32 ` Derrick Stolee
2018-10-12 16:15 ` Johannes Sixt
2018-10-13 8:05 ` Junio C Hamano
2018-09-21 17:39 ` [PATCH v3 5/7] commit/revisions: bookkeeping before refactoring Derrick Stolee via GitGitGadget
2018-10-11 14:21 ` Jeff King
2018-09-21 17:39 ` [PATCH v3 6/7] revision.h: add whitespace in flag definitions Derrick Stolee via GitGitGadget
2018-09-21 17:39 ` [PATCH v3 7/7] revision.c: refactor basic topo-order logic Derrick Stolee via GitGitGadget
2018-09-27 17:57 ` Derrick Stolee
2018-10-06 16:56 ` Jakub Narebski
2018-10-11 15:35 ` Jeff King
2018-10-11 16:21 ` Derrick Stolee
2018-10-25 9:43 ` Jeff King
2018-10-25 13:00 ` Derrick Stolee
2018-10-11 22:32 ` Stefan Beller
2018-09-21 21:22 ` [PATCH v3 0/7] Use generation numbers for --topo-order Junio C Hamano
2018-10-16 22:36 ` [PATCH v4 " Derrick Stolee via GitGitGadget
2018-10-16 22:36 ` [PATCH v4 1/7] prio-queue: add 'peek' operation Derrick Stolee via GitGitGadget
2018-10-16 22:36 ` [PATCH v4 2/7] test-reach: add run_three_modes method Derrick Stolee via GitGitGadget
2018-10-16 22:36 ` [PATCH v4 3/7] test-reach: add rev-list tests Derrick Stolee via GitGitGadget
2018-10-21 10:21 ` Jakub Narebski
2018-10-21 15:28 ` Derrick Stolee
2018-10-16 22:36 ` [PATCH v4 4/7] revision.c: begin refactoring --topo-order logic Derrick Stolee via GitGitGadget
2018-10-21 15:55 ` Jakub Narebski
2018-10-22 1:12 ` Junio C Hamano
2018-10-22 1:51 ` Derrick Stolee
2018-10-22 1:55 ` [RFC PATCH] revision.c: use new algorithm in A..B case Derrick Stolee
2018-10-25 8:28 ` [PATCH v4 4/7] revision.c: begin refactoring --topo-order logic Junio C Hamano
2018-10-26 20:56 ` Jakub Narebski
2018-10-16 22:36 ` [PATCH v4 5/7] commit/revisions: bookkeeping before refactoring Derrick Stolee via GitGitGadget
2018-10-21 21:17 ` Jakub Narebski
2018-10-16 22:36 ` [PATCH v4 6/7] revision.c: generation-based topo-order algorithm Derrick Stolee via GitGitGadget
2018-10-22 13:37 ` Jakub Narebski
2018-10-23 13:54 ` Derrick Stolee
2018-10-26 16:55 ` Jakub Narebski
2018-10-16 22:36 ` [PATCH v4 7/7] t6012: make rev-list tests more interesting Derrick Stolee via GitGitGadget
2018-10-23 15:48 ` Jakub Narebski
2018-10-21 12:57 ` [PATCH v4 0/7] Use generation numbers for --topo-order Jakub Narebski
2018-11-01 5:21 ` Junio C Hamano
2018-11-01 13:49 ` Derrick Stolee
2018-11-01 23:54 ` Junio C Hamano
2018-11-01 13:46 ` [PATCH v5 " Derrick Stolee
2018-11-01 13:46 ` [PATCH v5 1/7] prio-queue: add 'peek' operation Derrick Stolee
2018-11-01 13:46 ` [PATCH v5 2/7] test-reach: add run_three_modes method Derrick Stolee
2018-11-01 13:46 ` [PATCH v5 3/7] test-reach: add rev-list tests Derrick Stolee
2018-11-01 13:46 ` [PATCH v5 4/7] revision.c: begin refactoring --topo-order logic Derrick Stolee
2018-11-01 13:46 ` [PATCH v5 5/7] commit/revisions: bookkeeping before refactoring Derrick Stolee
2018-11-01 13:46 ` [PATCH v5 6/7] revision.c: generation-based topo-order algorithm Derrick Stolee
2018-11-01 15:48 ` SZEDER Gábor
2018-11-01 16:12 ` Derrick Stolee
2019-11-08 2:50 ` Mike Hommey
2019-11-11 1:07 ` Derrick Stolee
2019-11-18 23:04 ` SZEDER Gábor
2018-11-01 13:46 ` [PATCH v5 7/7] t6012: make rev-list tests more interesting Derrick Stolee
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