Mercurial > hg-stable
view contrib/hg-ssh @ 49773:523cacdfd324
delta-find: set the default candidate chunk size to 10
I ran performance and storage tests on repositories of various sizes and shapes
for the following values of the config : 5, 10, 20, 50, 100, no-chunking
The performance tests do not show any statistical impact on computation
times for large pushes and pulls.
For searching for an individual delta, this can provide a significant
performance improvement with a minor degradation of space-quality on the
result. (see data at the end of the commit).
For overall store size, the change :
- does not have any impact on many small repositories,
- has an observable, but very negligible impact on most larger repositories.
- One private repository we use for testing sees a small increase in size
(1%) in the narrower version.
We will try to get more numbers on a larger version of that repository to
make sure nothing pathological happens.
We pick "10" as the limit as "5" seems a bit more risky.
There are room to improve the current code, by using more aggressive filtering
and better (i.e any) sorting of the candidates. However this is already a large
improvement for pathological cases, with little impact in the common
situations.
The initial motivation for this change is to fix performance of delta
computation for a file where the previous code ended up testing 20 000 possible
candidate-bases in one go, which is… slow. This affected about ½ of the file
revisions leading to atrocious performance, especially during some push/pull
operations.
Details about individual delta finding timing:
----------------------------------------------
The vast majority of benchmark cases are unchanged but the three below. The first
two do not see any impact on the final delta. The last one sees a change in
delta-size that is negligible compared to the full text size.
### data-env-vars.name = mozilla-try-2019-02-18-zstd-sparse-revlog
# benchmark.name = perf-delta-find
# benchmark.variants.rev = manifest-snapshot-many-tries-a (revision 756096)
∞: 5.844783
5: 4.473523 (-23.46%)
10: 4.970053 (-14.97%)
20: 5.770386 (-1.27%)
50 5.821358
100: 5.834887
MANIFESTLOG: rev = 756096: (no-limit)
delta-base = 301840
search-rounds = 6
try-count = 60
delta-type = snapshot
snap-depth = 7
delta-size = 179
MANIFESTLOG: rev=756096: (limit = 10)
delta-base=301840
search-rounds=9
try-count=51
delta-type=snapshot
snap-depth=7
delta-size=179
### data-env-vars.name = mozilla-try-2019-02-18-zstd-sparse-revlog
# benchmark.name = perf-delta-find
# benchmark.variants.rev = manifest-snapshot-many-tries-d (revision 754060)
∞: 5.017663
5: 3.655931 (-27.14%)
10: 4.095436 (-18.38%)
20: 4.828949 (-3.76%)
50 4.987574
100: 4.994889
MANIFESTLOG: rev=754060: (no limit)
delta-base=301840
search-rounds=5
try-count=53
delta-type=snapshot
snap-depth=7
delta-size = 179
MANIFESTLOG: rev=754060: (limite = 10)
delta-base=301840
search-rounds=8
try-count=45
delta-type=snapshot
snap-depth=7
delta-size = 179
### data-env-vars.name = mozilla-try-2019-02-18-zstd-sparse-revlog
# benchmark.name = perf-delta-find
# bin-env-vars.hg.flavor = rust
# benchmark.variants.rev = manifest-snapshot-many-tries-e (revision 693368)
∞: 4.869282
5: 2.039732 (-58.11%)
10: 2.413537 (-50.43%)
20: 4.449639 (-8.62%)
50 4.865863
100: 4.882649
MANIFESTLOG: rev=693368:
delta-base=693336
search-rounds=6
try-count=53
delta-type=snapshot
snap-depth=6
full-test-size=131065
delta-size=199
MANIFESTLOG: rev=693368:
delta-base=278023
search-rounds=5
try-count=21
delta-type=snapshot
snap-depth=4
full-test-size=131065
delta-size=278
Raw data for store size (in bytes) for various chunk size value below:
----------------------------------------------------------------------
440 134 384 5 pypy/.hg/store/
440 134 384 10 pypy/.hg/store/
440 134 384 20 pypy/.hg/store/
440 134 384 50 pypy/.hg/store/
440 134 384 100 pypy/.hg/store/
440 134 384 ... pypy/.hg/store/
666 987 471 5 netbsd-xsrc-2022-11-15/.hg/store/
666 987 471 10 netbsd-xsrc-2022-11-15/.hg/store/
666 987 471 20 netbsd-xsrc-2022-11-15/.hg/store/
666 987 471 50 netbsd-xsrc-2022-11-15/.hg/store/
666 987 471 100 netbsd-xsrc-2022-11-15/.hg/store/
666 987 471 ... netbsd-xsrc-2022-11-15/.hg/store/
852 844 884 5 netbsd-pkgsrc-2022-11-15/.hg/store/
852 844 884 10 netbsd-pkgsrc-2022-11-15/.hg/store/
852 844 884 20 netbsd-pkgsrc-2022-11-15/.hg/store/
852 844 884 50 netbsd-pkgsrc-2022-11-15/.hg/store/
852 844 884 100 netbsd-pkgsrc-2022-11-15/.hg/store/
852 844 884 ... netbsd-pkgsrc-2022-11-15/.hg/store/
1 504 227 981 5 netbeans-2018-08-01-sparse-zstd/.hg/store/
1 504 227 871 10 netbeans-2018-08-01-sparse-zstd/.hg/store/
1 504 227 813 20 netbeans-2018-08-01-sparse-zstd/.hg/store/
1 504 227 813 50 netbeans-2018-08-01-sparse-zstd/.hg/store/
1 504 227 813 100 netbeans-2018-08-01-sparse-zstd/.hg/store/
1 504 227 813 ... netbeans-2018-08-01-sparse-zstd/.hg/store/
3 875 801 068 5 netbsd-src-2022-11-15/.hg/store/
3 875 696 767 10 netbsd-src-2022-11-15/.hg/store/
3 875 696 757 20 netbsd-src-2022-11-15/.hg/store/
3 875 696 653 50 netbsd-src-2022-11-15/.hg/store/
3 875 696 653 100 netbsd-src-2022-11-15/.hg/store/
3 875 696 653 ... netbsd-src-2022-11-15/.hg/store/
4 531 441 314 5 mozilla-central/.hg/store/
4 531 435 157 10 mozilla-central/.hg/store/
4 531 432 045 20 mozilla-central/.hg/store/
4 531 429 119 50 mozilla-central/.hg/store/
4 531 429 119 100 mozilla-central/.hg/store/
4 531 429 119 ... mozilla-central/.hg/store/
4 875 861 390 5 mozilla-unified/.hg/store/
4 875 855 155 10 mozilla-unified/.hg/store/
4 875 852 027 20 mozilla-unified/.hg/store/
4 875 848 851 50 mozilla-unified/.hg/store/
4 875 848 851 100 mozilla-unified/.hg/store/
4 875 848 851 ... mozilla-unified/.hg/store/
11 498 764 601 5 mozilla-try/.hg/store/
11 497 968 858 10 mozilla-try/.hg/store/
11 497 958 730 20 mozilla-try/.hg/store/
11 497 927 156 50 mozilla-try/.hg/store/
11 497 925 963 100 mozilla-try/.hg/store/
11 497 923 428 ... mozilla-try/.hg/store/
10 047 914 031 5 private-repo
9 969 132 101 10 private-repo
9 944 745 015 20 private-repo
9 939 756 703 50 private-repo
9 939 833 016 100 private-repo
9 939 822 035 ... private-repo
author | Pierre-Yves David <pierre-yves.david@octobus.net> |
---|---|
date | Wed, 23 Nov 2022 19:08:27 +0100 |
parents | 6000f5b25c9b |
children |
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#!/usr/bin/env python3 # # Copyright 2005-2007 by Intevation GmbH <intevation@intevation.de> # # Author(s): # Thomas Arendsen Hein <thomas@intevation.de> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. """ hg-ssh - a wrapper for ssh access to a limited set of mercurial repos To be used in ~/.ssh/authorized_keys with the "command" option, see sshd(8): command="hg-ssh path/to/repo1 /path/to/repo2 ~/repo3 ~user/repo4" ssh-dss ... (probably together with these other useful options: no-port-forwarding,no-X11-forwarding,no-agent-forwarding) This allows pull/push over ssh from/to the repositories given as arguments. If all your repositories are subdirectories of a common directory, you can allow shorter paths with: command="cd path/to/my/repositories && hg-ssh repo1 subdir/repo2" You can use pattern matching of your normal shell, e.g.: command="cd repos && hg-ssh user/thomas/* projects/{mercurial,foo}" You can also add a --read-only flag to allow read-only access to a key, e.g.: command="hg-ssh --read-only repos/*" """ import os import re import shlex import sys # enable importing on demand to reduce startup time import hgdemandimport hgdemandimport.enable() from mercurial import ( dispatch, pycompat, ui as uimod, ) def main(): # Prevent insertion/deletion of CRs dispatch.initstdio() cwd = os.getcwd() if os.name == 'nt': # os.getcwd() is inconsistent on the capitalization of the drive # letter, so adjust it. see https://bugs.python.org/issue40368 if re.match('^[a-z]:', cwd): cwd = cwd[0:1].upper() + cwd[1:] readonly = False args = sys.argv[1:] while len(args): if args[0] == '--read-only': readonly = True args.pop(0) else: break allowed_paths = [ os.path.normpath(os.path.join(cwd, os.path.expanduser(path))) for path in args ] orig_cmd = os.getenv('SSH_ORIGINAL_COMMAND', '?') try: cmdargv = shlex.split(orig_cmd) except ValueError as e: sys.stderr.write('Illegal command "%s": %s\n' % (orig_cmd, e)) sys.exit(255) if cmdargv[:2] == ['hg', '-R'] and cmdargv[3:] == ['serve', '--stdio']: path = cmdargv[2] repo = os.path.normpath(os.path.join(cwd, os.path.expanduser(path))) if repo in allowed_paths: cmd = [b'-R', pycompat.fsencode(repo), b'serve', b'--stdio'] req = dispatch.request(cmd) if readonly: if not req.ui: req.ui = uimod.ui.load() req.ui.setconfig( b'hooks', b'pretxnopen.hg-ssh', b'python:__main__.rejectpush', b'hg-ssh', ) req.ui.setconfig( b'hooks', b'prepushkey.hg-ssh', b'python:__main__.rejectpush', b'hg-ssh', ) dispatch.dispatch(req) else: sys.stderr.write('Illegal repository "%s"\n' % repo) sys.exit(255) else: sys.stderr.write('Illegal command "%s"\n' % orig_cmd) sys.exit(255) def rejectpush(ui, **kwargs): ui.warn((b"Permission denied\n")) # mercurial hooks use unix process conventions for hook return values # so a truthy return means failure return True if __name__ == '__main__': main()