Mercurial > hg
view tests/test-remotefilelog-wireproto.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 | 0800d9e6e216 |
children | dcaa2df1f688 |
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#require no-windows $ . "$TESTDIR/remotefilelog-library.sh" $ hg init master $ cd master $ cat >> .hg/hgrc <<EOF > [remotefilelog] > server=True > EOF $ echo x > x $ hg commit -qAm x $ echo y >> x $ hg commit -qAm y $ echo z >> x $ hg commit -qAm z $ hg update 1 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ echo w >> x $ hg commit -qAm w $ cd .. Shallow clone and activate getflogheads testing extension $ hgcloneshallow ssh://user@dummy/master shallow --noupdate streaming all changes 2 files to transfer, 908 bytes of data transferred 908 bytes in * seconds (*/sec) (glob) searching for changes no changes found $ cd shallow $ cat >> .hg/hgrc <<EOF > [extensions] > getflogheads=$TESTDIR/remotefilelog-getflogheads.py > EOF Get heads of a remotefilelog $ hg getflogheads x 2797809ca5e9c2f307d82b1345e832f655fb99a2 ca758b402ddc91e37e3113e1a97791b537e1b7bb Get heads of a non-existing remotefilelog $ hg getflogheads y EMPTY