Re: [PATCH 2/2] commit-graph: propagate topo_levels slab to all chain layers
From: Junio C Hamano <hidden>
Date: 2026-07-07 17:00:25
"Kristofer Karlsson via GitGitGadget" [off-list ref] writes:
From: Kristofer Karlsson <redacted> Fix a regression introduced in 199d452758 (commit-graph: fix "filling in" topological levels, 2025-04-07) where the loop
I guess the same comment from [1/2] applies. We might be chasing ghosts here. Is that elusive commit a total hallucination?
On a repository with 2.78M commits and a multi-layer split commit-graph, this caused a single incremental commit-graph write to spend ~3.7 seconds in the generation DFS instead of microseconds.
Nice.
quoted hunk ↗ jump to hunk
Signed-off-by: Kristofer Karlsson <redacted> --- commit-graph.c | 2 +- t/t5324-split-commit-graph.sh | 6 +----- 2 files changed, 2 insertions(+), 6 deletions(-)diff --git a/commit-graph.c b/commit-graph.c index 4e39a048c4..c2a711cceb 100644 --- a/commit-graph.c +++ b/commit-graph.c@@ -2610,7 +2610,7 @@ int write_commit_graph(struct odb_source *source, g = prepare_commit_graph(ctx.r); for (struct commit_graph *chain = g; chain; chain = chain->base_graph) - g->topo_levels = &topo_levels; + chain->topo_levels = &topo_levels; if (flags & COMMIT_GRAPH_WRITE_BLOOM_FILTERS) ctx.changed_paths = 1;diff --git a/t/t5324-split-commit-graph.sh b/t/t5324-split-commit-graph.sh index f9c57760f4..9e5ab7dbd0 100755 --- a/t/t5324-split-commit-graph.sh +++ b/t/t5324-split-commit-graph.sh@@ -738,11 +738,7 @@ test_expect_success 'incremental write reads topo levels from all layers' ' GIT_TRACE2_EVENT="$(pwd)/trace.txt" \ git commit-graph write --reachable --split=no-merge && - # BUG: topo levels from lower graph layers are not - # propagated, so the DFS re-walks from base-3 down to - # the root (7 steps) instead of reading topo levels - # from the existing graph (1 step). - test_trace2_data commit-graph generation-dfs-steps 7 <trace.txt + test_trace2_data commit-graph generation-dfs-steps 1 <trace.txt ) '