changelog: specify checkambig=True to revlog.__init__, to avoid ambiguity
If steps below occurs at "the same time in sec", all of mtime, ctime
and size are same between (1) and (3).
1. append data to 00changelog.i (and close transaction)
2. discard appended data by truncation (strip or rollback)
3. append same size but different data to 00changelog.i again
Therefore, cache validation doesn't work after (3) as expected.
To avoid such file stat ambiguity around truncation, this patch
specifies checkambig=True to revlog.__init__(). This makes revlog
write changes out with checkambig=True.
Even though changes of 00changelog.i themselves are written out at
changelog._finalize(), this checkambig=True is needed, because
revlog.checkinlinesize(), which is invoked at the end of
changelog._finalize(), might replace already changed 00changelog.i by
converted one.
Even after this patch, avoiding file stat ambiguity of 00changelog.i
around truncation isn't yet completed, because truncation side isn't
aware of this issue.
This is a part of ExactCacheValidationPlan.
https://www.mercurial-scm.org/wiki/ExactCacheValidationPlan
# profiling.py - profiling functions
#
# Copyright 2016 Gregory Szorc <gregory.szorc@gmail.com>
#
# 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, print_function
import contextlib
import os
import sys
import time
from .i18n import _
from . import (
error,
util,
)
@contextlib.contextmanager
def lsprofile(ui, fp):
format = ui.config('profiling', 'format', default='text')
field = ui.config('profiling', 'sort', default='inlinetime')
limit = ui.configint('profiling', 'limit', default=30)
climit = ui.configint('profiling', 'nested', default=0)
if format not in ['text', 'kcachegrind']:
ui.warn(_("unrecognized profiling format '%s'"
" - Ignored\n") % format)
format = 'text'
try:
from . import lsprof
except ImportError:
raise error.Abort(_(
'lsprof not available - install from '
'http://codespeak.net/svn/user/arigo/hack/misc/lsprof/'))
p = lsprof.Profiler()
p.enable(subcalls=True)
try:
yield
finally:
p.disable()
if format == 'kcachegrind':
from . import lsprofcalltree
calltree = lsprofcalltree.KCacheGrind(p)
calltree.output(fp)
else:
# format == 'text'
stats = lsprof.Stats(p.getstats())
stats.sort(field)
stats.pprint(limit=limit, file=fp, climit=climit)
@contextlib.contextmanager
def flameprofile(ui, fp):
try:
from flamegraph import flamegraph
except ImportError:
raise error.Abort(_(
'flamegraph not available - install from '
'https://github.com/evanhempel/python-flamegraph'))
# developer config: profiling.freq
freq = ui.configint('profiling', 'freq', default=1000)
filter_ = None
collapse_recursion = True
thread = flamegraph.ProfileThread(fp, 1.0 / freq,
filter_, collapse_recursion)
start_time = time.clock()
try:
thread.start()
yield
finally:
thread.stop()
thread.join()
print('Collected %d stack frames (%d unique) in %2.2f seconds.' % (
time.clock() - start_time, thread.num_frames(),
thread.num_frames(unique=True)))
@contextlib.contextmanager
def statprofile(ui, fp):
try:
import statprof
except ImportError:
raise error.Abort(_(
'statprof not available - install using "easy_install statprof"'))
freq = ui.configint('profiling', 'freq', default=1000)
if freq > 0:
# Cannot reset when profiler is already active. So silently no-op.
if statprof.state.profile_level == 0:
statprof.reset(freq)
else:
ui.warn(_("invalid sampling frequency '%s' - ignoring\n") % freq)
statprof.start()
try:
yield
finally:
statprof.stop()
statprof.display(fp)
@contextlib.contextmanager
def profile(ui):
"""Start profiling.
Profiling is active when the context manager is active. When the context
manager exits, profiling results will be written to the configured output.
"""
profiler = os.getenv('HGPROF')
if profiler is None:
profiler = ui.config('profiling', 'type', default='ls')
if profiler not in ('ls', 'stat', 'flame'):
ui.warn(_("unrecognized profiler '%s' - ignored\n") % profiler)
profiler = 'ls'
output = ui.config('profiling', 'output')
if output == 'blackbox':
fp = util.stringio()
elif output:
path = ui.expandpath(output)
fp = open(path, 'wb')
else:
fp = sys.stderr
try:
if profiler == 'ls':
proffn = lsprofile
elif profiler == 'flame':
proffn = flameprofile
else:
proffn = statprofile
with proffn(ui, fp):
yield
finally:
if output:
if output == 'blackbox':
val = 'Profile:\n%s' % fp.getvalue()
# ui.log treats the input as a format string,
# so we need to escape any % signs.
val = val.replace('%', '%%')
ui.log('profile', val)
fp.close()
@contextlib.contextmanager
def maybeprofile(ui):
"""Profile if enabled, else do nothing.
This context manager can be used to optionally profile if profiling
is enabled. Otherwise, it does nothing.
The purpose of this context manager is to make calling code simpler:
just use a single code path for calling into code you may want to profile
and this function determines whether to start profiling.
"""
if ui.configbool('profiling', 'enabled'):
with profile(ui):
yield
else:
yield