Mercurial > hg
view tests/test-merge-closedheads.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 $REPO --config experimental.dirstate-tree.in-memory=1
then visualizing the recorded JSON file in https://www.speedscope.app/
Differential Revision: https://phab.mercurial-scm.org/D10554
author | Simon Sapin <simon.sapin@octobus.net> |
---|---|
date | Fri, 30 Apr 2021 14:22:14 +0200 |
parents | 8197b395710e |
children |
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$ hgcommit() { > hg commit -u user "$@" > } $ hg init clhead $ cd clhead $ touch foo && hg add && hgcommit -m 'foo' adding foo $ touch bar && hg add && hgcommit -m 'bar' adding bar $ touch baz && hg add && hgcommit -m 'baz' adding baz $ echo "flub" > foo $ hgcommit -m "flub" $ echo "nub" > foo $ hgcommit -m "nub" $ hg up -C 2 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ echo "c1" > c1 $ hg add c1 $ hgcommit -m "c1" created new head $ echo "c2" > c1 $ hgcommit -m "c2" $ hg up -C 2 0 files updated, 0 files merged, 1 files removed, 0 files unresolved $ echo "d1" > d1 $ hg add d1 $ hgcommit -m "d1" created new head $ echo "d2" > d1 $ hgcommit -m "d2" $ hg tag -l good fail with three heads $ hg up -C good 0 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg merge abort: branch 'default' has 3 heads - please merge with an explicit rev (run 'hg heads .' to see heads, specify rev with -r) [255] close one of the heads $ hg up -C 6 1 files updated, 0 files merged, 1 files removed, 0 files unresolved $ hgcommit -m 'close this head' --close-branch succeed with two open heads $ hg up -C good 1 files updated, 0 files merged, 1 files removed, 0 files unresolved $ hg up -C good 0 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg merge 1 files updated, 0 files merged, 0 files removed, 0 files unresolved (branch merge, don't forget to commit) $ hgcommit -m 'merged heads' hg update -C 8 $ hg update -C 8 1 files updated, 0 files merged, 0 files removed, 0 files unresolved hg branch some-branch $ hg branch some-branch marked working directory as branch some-branch (branches are permanent and global, did you want a bookmark?) hg commit $ hgcommit -m 'started some-branch' hg commit --close-branch $ hgcommit --close-branch -m 'closed some-branch' hg update default $ hg update default 1 files updated, 0 files merged, 0 files removed, 0 files unresolved hg merge some-branch $ hg merge some-branch 0 files updated, 0 files merged, 0 files removed, 0 files unresolved (branch merge, don't forget to commit) hg commit (no reopening of some-branch) $ hgcommit -m 'merge with closed branch' $ cd ..