Mercurial > hg
view tests/md5sum.py @ 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 | c102b704edb5 |
children | 6000f5b25c9b |
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#!/usr/bin/env python3 # # Based on python's Tools/scripts/md5sum.py # # This software may be used and distributed according to the terms # of the PYTHON SOFTWARE FOUNDATION LICENSE VERSION 2, which is # GPL-compatible. from __future__ import absolute_import import hashlib import os import sys try: import msvcrt msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY) msvcrt.setmode(sys.stderr.fileno(), os.O_BINARY) except ImportError: pass for filename in sys.argv[1:]: try: fp = open(filename, 'rb') except IOError as msg: sys.stderr.write('%s: Can\'t open: %s\n' % (filename, msg)) sys.exit(1) m = hashlib.md5() try: for data in iter(lambda: fp.read(8192), b''): m.update(data) except IOError as msg: sys.stderr.write('%s: I/O error: %s\n' % (filename, msg)) sys.exit(1) sys.stdout.write('%s %s\n' % (m.hexdigest(), filename)) sys.exit(0)