##// END OF EJS Templates
compression: introduce a `storage.revlog.zlib.level` configuration...
compression: introduce a `storage.revlog.zlib.level` configuration This option control the zlib compression level used when compression revlog chunk. This is also a good excuse to pave the way for a similar configuration option for the zstd compression engine. Having a dedicated option for each compression algorithm is useful because they don't support the same range of values. Using a higher zlib compression impact CPU consumption at compression time, but does not directly affected decompression time. However dealing with small compressed chunk can directly help decompression and indirectly help other revlog logic. I ran some basic test on repositories using different level. I am using the mercurial, pypy, netbeans and mozilla-central clone from our benchmark suite. All tested repository use sparse-revlog and got all their delta recomputed. The different compression level has a small effect on the repository size (about 10% variation in the total range). My quick analysis is that revlog mostly store small delta, that are not affected by the compression level much. So the variation probably mostly comes from better compression of the snapshots revisions, and snapshot revision only represent a small portion of the repository content. I also made some basic timings measurements. The "read" timings are gathered using simple run of `hg perfrevlogrevisions`, the "write" timings using `hg perfrevlogwrite` (restricted to the last 5000 revisions for netbeans and mozilla central). The timings are gathered on a generic machine, (not one of our performance locked machine), so small variation might not be meaningful. However large trend remains relevant. Keep in mind that these numbers are not pure compression/decompression time. They also involve the full revlog logic. In particular the difference in chunk size has an impact on the delta chain structure, affecting performance when writing or reading them. On read/write performance, the compression level has a bigger impact. Counter-intuitively, the higher compression levels improve "write" performance for the large repositories in our tested setting. Maybe because the last 5000 delta chain end up having a very different shape in this specific spot? Or maybe because of a more general trend of better delta chains thanks to the smaller chunk and snapshot. This series does not intend to change the default compression level. However, these result call for a deeper analysis of this performance difference in the future. Full data ========= repo level .hg/store size 00manifest.d read write ---------------------------------------------------------------- mercurial 1 49,402,813 5,963,475 0.170159 53.250304 mercurial 6 47,197,397 5,875,730 0.182820 56.264320 mercurial 9 47,121,596 5,849,781 0.189219 56.293612 pypy 1 370,830,572 28,462,425 2.679217 460.721984 pypy 6 340,112,317 27,648,747 2.768691 467.537158 pypy 9 338,360,736 27,639,003 2.763495 476.589918 netbeans 1 1,281,847,810 165,495,457 122.477027 520.560316 netbeans 6 1,205,284,353 159,161,207 139.876147 715.930400 netbeans 9 1,197,135,671 155,034,586 141.620281 678.297064 mozilla 1 2,775,497,186 298,527,987 147.867662 751.263721 mozilla 6 2,596,856,420 286,597,671 170.572118 987.056093 mozilla 9 2,587,542,494 287,018,264 163.622338 739.803002

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transport.py
132 lines | 4.9 KiB | text/x-python | PythonLexer
# -*- coding: utf-8 -*-
# Copyright (C) 2007 Daniel Holth <dholth@fastmail.fm>
# This is a stripped-down version of the original bzr-svn transport.py,
# Copyright (C) 2006 Jelmer Vernooij <jelmer@samba.org>
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
# You should have received a copy of the GNU General Public License
# along with this program; if not, see <http://www.gnu.org/licenses/>.
from __future__ import absolute_import
import svn.client
import svn.core
import svn.ra
Pool = svn.core.Pool
SubversionException = svn.core.SubversionException
from mercurial import (
util,
)
# Some older versions of the Python bindings need to be
# explicitly initialized. But what we want to do probably
# won't work worth a darn against those libraries anyway!
svn.ra.initialize()
svn_config = None
def _create_auth_baton(pool):
"""Create a Subversion authentication baton. """
import svn.client
# Give the client context baton a suite of authentication
# providers.h
providers = [
svn.client.get_simple_provider(pool),
svn.client.get_username_provider(pool),
svn.client.get_ssl_client_cert_file_provider(pool),
svn.client.get_ssl_client_cert_pw_file_provider(pool),
svn.client.get_ssl_server_trust_file_provider(pool),
]
# Platform-dependent authentication methods
getprovider = getattr(svn.core, 'svn_auth_get_platform_specific_provider',
None)
if getprovider:
# Available in svn >= 1.6
for name in ('gnome_keyring', 'keychain', 'kwallet', 'windows'):
for type in ('simple', 'ssl_client_cert_pw', 'ssl_server_trust'):
p = getprovider(name, type, pool)
if p:
providers.append(p)
else:
if util.safehasattr(svn.client, 'get_windows_simple_provider'):
providers.append(svn.client.get_windows_simple_provider(pool))
return svn.core.svn_auth_open(providers, pool)
class NotBranchError(SubversionException):
pass
class SvnRaTransport(object):
"""
Open an ra connection to a Subversion repository.
"""
def __init__(self, url="", ra=None):
self.pool = Pool()
self.svn_url = url
self.username = ''
self.password = ''
# Only Subversion 1.4 has reparent()
if ra is None or not util.safehasattr(svn.ra, 'reparent'):
self.client = svn.client.create_context(self.pool)
ab = _create_auth_baton(self.pool)
self.client.auth_baton = ab
global svn_config
if svn_config is None:
svn_config = svn.core.svn_config_get_config(None)
self.client.config = svn_config
try:
self.ra = svn.client.open_ra_session(
self.svn_url,
self.client, self.pool)
except SubversionException as xxx_todo_changeme:
(inst, num) = xxx_todo_changeme.args
if num in (svn.core.SVN_ERR_RA_ILLEGAL_URL,
svn.core.SVN_ERR_RA_LOCAL_REPOS_OPEN_FAILED,
svn.core.SVN_ERR_BAD_URL):
raise NotBranchError(url)
raise
else:
self.ra = ra
svn.ra.reparent(self.ra, self.svn_url.encode('utf8'))
class Reporter(object):
def __init__(self, reporter_data):
self._reporter, self._baton = reporter_data
def set_path(self, path, revnum, start_empty, lock_token, pool=None):
svn.ra.reporter2_invoke_set_path(self._reporter, self._baton,
path, revnum, start_empty, lock_token, pool)
def delete_path(self, path, pool=None):
svn.ra.reporter2_invoke_delete_path(self._reporter, self._baton,
path, pool)
def link_path(self, path, url, revision, start_empty, lock_token,
pool=None):
svn.ra.reporter2_invoke_link_path(self._reporter, self._baton,
path, url, revision, start_empty, lock_token,
pool)
def finish_report(self, pool=None):
svn.ra.reporter2_invoke_finish_report(self._reporter,
self._baton, pool)
def abort_report(self, pool=None):
svn.ra.reporter2_invoke_abort_report(self._reporter,
self._baton, pool)
def do_update(self, revnum, path, *args, **kwargs):
return self.Reporter(svn.ra.do_update(self.ra, revnum, path,
*args, **kwargs))