Mercurial > hg
view tests/test-convert-bzr-treeroot.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 | 5abc47d4ca6b |
children | 26127236b229 |
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#require bzr $ . "$TESTDIR/bzr-definitions" $ cat > treeset.py <<EOF > import sys > from bzrlib import workingtree > wt = workingtree.WorkingTree.open('.') > > message, rootid = sys.argv[1:] > wt.set_root_id('tree_root-%s' % rootid) > wt.commit(message) > EOF change the id of the tree root $ mkdir test-change-treeroot-id $ cd test-change-treeroot-id $ bzr init -q source $ cd source $ echo content > file $ bzr add -q file $ bzr commit -q -m 'Initial add' $ "$PYTHON" ../../treeset.py 'Changed root' new $ cd .. $ hg convert source source-hg initializing destination source-hg repository scanning source... sorting... converting... 1 Initial add 0 Changed root $ manifest source-hg tip % manifest of tip 644 file $ cd ..