Mercurial > hg
view tests/test-unrelated-pull.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 $REPO --config experimental.dirstate-tree.in-memory=1
then visualizing the recorded JSON file in https://www.speedscope.app/
Differential Revision: https://phab.mercurial-scm.org/D10554
author | Simon Sapin <simon.sapin@octobus.net> |
---|---|
date | Fri, 30 Apr 2021 14:22:14 +0200 |
parents | eb586ed5d8ce |
children |
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$ hg init a $ cd a $ echo 123 > a $ hg add a $ hg commit -m "a" -u a $ cd .. $ hg init b $ cd b $ echo 321 > b $ hg add b $ hg commit -m "b" -u b $ hg pull ../a pulling from ../a searching for changes abort: repository is unrelated [255] $ hg pull -f ../a pulling from ../a searching for changes warning: repository is unrelated requesting all changes adding changesets adding manifests adding file changes added 1 changesets with 1 changes to 1 files (+1 heads) new changesets 9a79c33a9db3 (run 'hg heads' to see heads, 'hg merge' to merge) $ hg heads changeset: 1:9a79c33a9db3 tag: tip parent: -1:000000000000 user: a date: Thu Jan 01 00:00:00 1970 +0000 summary: a changeset: 0:01f8062b2de5 user: b date: Thu Jan 01 00:00:00 1970 +0000 summary: b $ cd ..