##// END OF EJS Templates
discovery: slowly increase sampling size...
discovery: slowly increase sampling size Some pathological discovery runs can requires many roundtrip. When this happens things can get very slow. To make the algorithm more resilience again such pathological case. We slowly increase the sample size with each roundtrip (+5%). This will have a negligible impact on "normal" discovery with few roundtrips, but a large positive impact of case with many roundtrips. Asking more question per roundtrip helps to reduce the undecided set faster. Instead of reducing the undecided set a linear speed (in the worst case), we reduce it as a guaranteed (small) exponential rate. The data below show this slow ramp up in sample size: round trip | 1 | 5 | 10 | 20 | 50 | 100 | 130 | sample size | 200 | 254 | 321 | 517 | 2 199 | 25 123 | 108 549 | covered nodes | 200 | 1 357 | 2 821 | 7 031 | 42 658 | 524 530 | 2 276 755 | To be a bit more concrete, lets take a very pathological case as an example. We are doing discovery from a copy of Mozilla-try to a more recent version of mozilla-unified. Mozilla-unified heads are unknown to the mozilla-try repo and there are over 1 million "missing" changesets. (the discovery is "local" to avoid network interference) Without this change, the discovery: - last 1858 seconds (31 minutes), - does 1700 round trip, - asking about 340 000 nodes. With this change, the discovery: - last 218 seconds (3 minutes, 38 seconds a -88% improvement), - does 94 round trip (-94%), - asking about 344 211 nodes (+1%). Of course, this is an extreme case (and 3 minutes is still slow). However this give a good example of how this sample size increase act as a safety net catching any bad situations. We could image a steeper increase than 5%. For example 10% would give the following number: round trip | 1 | 5 | 10 | 20 | 50 | 75 | 100 | sample size | 200 | 321 | 514 | 1 326 | 23 060 | 249 812 | 2 706 594 | covered nodes | 200 | 1 541 | 3 690 | 12 671 | 251 871 | 2 746 254 | 29 770 966 | In parallel, it is useful to understand these pathological cases and improve them. However the current change provides a general purpose safety net to smooth the impact of pathological cases. To avoid issue with older http server, the increase in sample size only occurs if the protocol has not limit on command argument size.

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rcutil.py
99 lines | 3.1 KiB | text/x-python | PythonLexer
# rcutil.py - utilities about config paths, special config sections etc.
#
# Copyright Mercurial Contributors
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
from __future__ import absolute_import
import os
from . import (
encoding,
pycompat,
util,
)
if pycompat.iswindows:
from . import scmwindows as scmplatform
else:
from . import scmposix as scmplatform
fallbackpager = scmplatform.fallbackpager
systemrcpath = scmplatform.systemrcpath
userrcpath = scmplatform.userrcpath
def _expandrcpath(path):
'''path could be a file or a directory. return a list of file paths'''
p = util.expandpath(path)
if os.path.isdir(p):
join = os.path.join
return sorted(join(p, f) for f, k in util.listdir(p)
if f.endswith('.rc'))
return [p]
def envrcitems(env=None):
'''Return [(section, name, value, source)] config items.
The config items are extracted from environment variables specified by env,
used to override systemrc, but not userrc.
If env is not provided, encoding.environ will be used.
'''
if env is None:
env = encoding.environ
checklist = [
('EDITOR', 'ui', 'editor'),
('VISUAL', 'ui', 'editor'),
('PAGER', 'pager', 'pager'),
]
result = []
for envname, section, configname in checklist:
if envname not in env:
continue
result.append((section, configname, env[envname], '$%s' % envname))
return result
def defaultrcpath():
'''return rc paths in default.d'''
path = []
defaultpath = os.path.join(util.datapath, 'default.d')
if os.path.isdir(defaultpath):
path = _expandrcpath(defaultpath)
return path
def rccomponents():
'''return an ordered [(type, obj)] about where to load configs.
respect $HGRCPATH. if $HGRCPATH is empty, only .hg/hgrc of current repo is
used. if $HGRCPATH is not set, the platform default will be used.
if a directory is provided, *.rc files under it will be used.
type could be either 'path' or 'items', if type is 'path', obj is a string,
and is the config file path. if type is 'items', obj is a list of (section,
name, value, source) that should fill the config directly.
'''
envrc = ('items', envrcitems())
if 'HGRCPATH' in encoding.environ:
# assume HGRCPATH is all about user configs so environments can be
# overridden.
_rccomponents = [envrc]
for p in encoding.environ['HGRCPATH'].split(pycompat.ospathsep):
if not p:
continue
_rccomponents.extend(('path', p) for p in _expandrcpath(p))
else:
normpaths = lambda paths: [('path', os.path.normpath(p)) for p in paths]
_rccomponents = normpaths(defaultrcpath() + systemrcpath())
_rccomponents.append(envrc)
_rccomponents.extend(normpaths(userrcpath()))
return _rccomponents
def defaultpagerenv():
'''return a dict of default environment variables and their values,
intended to be set before starting a pager.
'''
return {'LESS': 'FRX', 'LV': '-c'}