Mercurial > hg
view tests/test-casecollision.t @ 47120:7109a38830c9
dirstate-tree: Fold "tracked descendants" counter update in main walk
For the purpose of implementing `has_tracked_dir` (which means "has tracked
descendants) without an expensive sub-tree traversal, we maintaing a counter
of tracked descendants on each "directory" node of the tree-shaped dirstate.
Before this changeset, mutating or inserting a node at a given path would
involve:
* Walking the tree from root through ancestors to find the node or the spot
where to insert it
* Looking at the previous node if any to decide what counter update is needed
* Performing any node mutation
* Walking the tree *again* to update counters in ancestor nodes
When profiling `hg status` on a large repo, this second walk takes times
while loading a the dirstate from disk.
It turns out we have enough information to decide before he first tree walk
what counter update is needed. This changeset merges the two walks, gaining
~10% of the total time for `hg update` (in the same hyperfine benchmark as
the previous changeset).
---
Profiling was done by compiling with this `.cargo/config`:
[profile.release]
debug = true
then running with:
py-spy record -r 500 -n -o /tmp/hg.json --format speedscope -- \
./hg status -R $REPO --config experimental.dirstate-tree.in-memory=1
then visualizing the recorded JSON file in https://www.speedscope.app/
Differential Revision: https://phab.mercurial-scm.org/D10554
author | Simon Sapin <simon.sapin@octobus.net> |
---|---|
date | Fri, 30 Apr 2021 14:22:14 +0200 |
parents | 7a9cbb315d84 |
children | 0b8e076e878c |
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#require no-icasefs test file addition with colliding case $ hg init repo1 $ cd repo1 $ echo a > a $ echo A > A $ hg add a $ hg st A a ? A $ hg add --config ui.portablefilenames=abort A abort: possible case-folding collision for A [255] $ hg st A a ? A $ hg add A warning: possible case-folding collision for A $ hg st A A A a $ hg forget A $ hg st A a ? A $ hg add --config ui.portablefilenames=no A $ hg st A A A a $ mkdir b $ touch b/c b/D $ hg add b adding b/D adding b/c $ touch b/d b/C $ hg add b/C warning: possible case-folding collision for b/C $ hg add b/d warning: possible case-folding collision for b/d $ touch b/a1 b/a2 $ hg add b adding b/a1 adding b/a2 $ touch b/A2 b/a1.1 $ hg add b/a1.1 b/A2 warning: possible case-folding collision for b/A2 $ touch b/f b/F $ hg add b/f b/F warning: possible case-folding collision for b/f $ touch g G $ hg add g G warning: possible case-folding collision for g $ mkdir h H $ touch h/x H/x $ hg add h/x H/x warning: possible case-folding collision for h/x $ touch h/s H/s $ hg add h/s $ hg add H/s warning: possible case-folding collision for H/s case changing rename must not warn or abort $ echo c > c $ hg ci -qAmx $ hg mv c C $ cd ..