Mercurial > hg
view tests/test-update-atomic.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 | 0826d684a1b5 |
children | 1d075b857c90 |
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#require execbit unix-permissions no-chg Checking that experimental.atomic-file works. $ cat > $TESTTMP/show_mode.py <<EOF > from __future__ import print_function > import os > import stat > import sys > ST_MODE = stat.ST_MODE > > for file_path in sys.argv[1:]: > file_stat = os.stat(file_path) > octal_mode = oct(file_stat[ST_MODE] & 0o777).replace('o', '') > print("%s:%s" % (file_path, octal_mode)) > > EOF $ hg init repo $ cd repo $ cat > .hg/showwrites.py <<EOF > from __future__ import print_function > from mercurial import pycompat > from mercurial.utils import stringutil > def uisetup(ui): > from mercurial import vfs > class newvfs(vfs.vfs): > def __call__(self, *args, **kwargs): > print(pycompat.sysstr(stringutil.pprint( > ('vfs open', args, sorted(list(kwargs.items())))))) > return super(newvfs, self).__call__(*args, **kwargs) > vfs.vfs = newvfs > EOF $ for v in a1 a2 b1 b2 c ro; do echo $v > $v; done $ chmod +x b* $ hg commit -Aqm _ # We check that # - the changes are actually atomic # - that permissions are correct (all 4 cases of (executable before) * (executable after)) # - that renames work, though they should be atomic anyway # - that it works when source files are read-only (but directories are read-write still) $ for v in a1 a2 b1 b2 ro; do echo changed-$v > $v; done $ chmod -x *1; chmod +x *2 $ hg rename c d $ hg commit -qm _ Check behavior without update.atomic-file $ hg update -r 0 -q $ hg update -r 1 --config extensions.showwrites=.hg/showwrites.py 2>&1 | grep "a1'.*wb" ('vfs open', ('a1', 'wb'), [('atomictemp', False), ('backgroundclose', True)]) $ $PYTHON $TESTTMP/show_mode.py * a1:0644 a2:0755 b1:0644 b2:0755 d:0644 ro:0644 Add a second revision for the ro file so we can test update when the file is present or not $ echo "ro" > ro $ hg commit -qm _ Check behavior without update.atomic-file first $ hg update -C -r 0 -q $ hg update -r 1 6 files updated, 0 files merged, 1 files removed, 0 files unresolved $ $PYTHON $TESTTMP/show_mode.py * a1:0644 a2:0755 b1:0644 b2:0755 d:0644 ro:0644 Manually reset the mode of the read-only file $ chmod a-w ro $ $PYTHON $TESTTMP/show_mode.py ro ro:0444 Now the file is present, try to update and check the permissions of the file $ hg up -r 2 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ $PYTHON $TESTTMP/show_mode.py ro ro:0644 # The file which was read-only is now writable in the default behavior Check behavior with update.atomic-files $ cat >> .hg/hgrc <<EOF > [experimental] > update.atomic-file = true > EOF $ hg update -C -r 0 -q $ hg update -r 1 --config extensions.showwrites=.hg/showwrites.py 2>&1 | grep "a1'.*wb" ('vfs open', ('a1', 'wb'), [('atomictemp', True), ('backgroundclose', True)]) $ hg st -A --rev 1 C a1 C a2 C b1 C b2 C d C ro Check the file permission after update $ $PYTHON $TESTTMP/show_mode.py * a1:0644 a2:0755 b1:0644 b2:0755 d:0644 ro:0644 Manually reset the mode of the read-only file $ chmod a-w ro $ $PYTHON $TESTTMP/show_mode.py ro ro:0444 Now the file is present, try to update and check the permissions of the file $ hg update -r 2 --traceback 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ $PYTHON $TESTTMP/show_mode.py ro ro:0644 # The behavior is the same as without atomic update