revlog: use existing file handle when reading during _addrevision
_addrevision() may need to read from revlogs as part of computing
deltas. Previously, we would flush existing file handles and open
a new, short-lived file handle to perform the reading.
If we have an existing file handle, it seems logical to reuse it
for reading instead of opening a new file handle. This patch
makes that the new behavior.
After this patch, revlog files are only reopened when adding
revisions if the revlog is switched from inline to non-inline.
On Linux when unbundling a bundle of the mozilla-central repo, this
patch has the following impact on system call counts:
Call Before After Delta
write 827,639 673,390 -154,249
open 700,103 684,089 -16,014
read 74,489 74,489 0
fstat 493,924 461,896 -32,028
close 249,131 233,117 -16,014
stat 242,001 242,001 0
lstat 18,676 18,676 0
lseek 20,268 20,268 0
ioctl 14,652 13,173 -1,479
TOTAL 3,180,758 2,930,679 -250,079
It's worth noting that many of the open() calls fail due to missing
files. That's why there are many more open() calls than close().
Despite the significant system call reduction, this change does not
seem to have a significant performance impact on Linux.
On Windows 10 (not a VM, on a SSD), this patch appears to reduce
unbundle time for mozilla-central from ~960s to ~920s. This isn't
as significant as I was hoping. But a decrease it is nonetheless.
Still, Windows unbundle performance is still >2x slower than Linux.
Despite the lack of significant gains, fewer system calls is fewer
system calls. If nothing else, this will narrow the focus of potential
areas to optimize in the future.
# formatter.py - generic output formatting for mercurial
#
# Copyright 2012 Matt Mackall <mpm@selenic.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
import cPickle
import os
from .i18n import _
from .node import (
hex,
short,
)
from . import (
encoding,
templater,
util,
)
class baseformatter(object):
def __init__(self, ui, topic, opts):
self._ui = ui
self._topic = topic
self._style = opts.get("style")
self._template = opts.get("template")
self._item = None
# function to convert node to string suitable for this output
self.hexfunc = hex
def __nonzero__(self):
'''return False if we're not doing real templating so we can
skip extra work'''
return True
def _showitem(self):
'''show a formatted item once all data is collected'''
pass
def startitem(self):
'''begin an item in the format list'''
if self._item is not None:
self._showitem()
self._item = {}
def data(self, **data):
'''insert data into item that's not shown in default output'''
self._item.update(data)
def write(self, fields, deftext, *fielddata, **opts):
'''do default text output while assigning data to item'''
fieldkeys = fields.split()
assert len(fieldkeys) == len(fielddata)
self._item.update(zip(fieldkeys, fielddata))
def condwrite(self, cond, fields, deftext, *fielddata, **opts):
'''do conditional write (primarily for plain formatter)'''
fieldkeys = fields.split()
assert len(fieldkeys) == len(fielddata)
self._item.update(zip(fieldkeys, fielddata))
def plain(self, text, **opts):
'''show raw text for non-templated mode'''
pass
def end(self):
'''end output for the formatter'''
if self._item is not None:
self._showitem()
class plainformatter(baseformatter):
'''the default text output scheme'''
def __init__(self, ui, topic, opts):
baseformatter.__init__(self, ui, topic, opts)
if ui.debugflag:
self.hexfunc = hex
else:
self.hexfunc = short
def __nonzero__(self):
return False
def startitem(self):
pass
def data(self, **data):
pass
def write(self, fields, deftext, *fielddata, **opts):
self._ui.write(deftext % fielddata, **opts)
def condwrite(self, cond, fields, deftext, *fielddata, **opts):
'''do conditional write'''
if cond:
self._ui.write(deftext % fielddata, **opts)
def plain(self, text, **opts):
self._ui.write(text, **opts)
def end(self):
pass
class debugformatter(baseformatter):
def __init__(self, ui, topic, opts):
baseformatter.__init__(self, ui, topic, opts)
self._ui.write("%s = [\n" % self._topic)
def _showitem(self):
self._ui.write(" " + repr(self._item) + ",\n")
def end(self):
baseformatter.end(self)
self._ui.write("]\n")
class pickleformatter(baseformatter):
def __init__(self, ui, topic, opts):
baseformatter.__init__(self, ui, topic, opts)
self._data = []
def _showitem(self):
self._data.append(self._item)
def end(self):
baseformatter.end(self)
self._ui.write(cPickle.dumps(self._data))
def _jsonifyobj(v):
if isinstance(v, tuple):
return '[' + ', '.join(_jsonifyobj(e) for e in v) + ']'
elif v is None:
return 'null'
elif v is True:
return 'true'
elif v is False:
return 'false'
elif isinstance(v, (int, float)):
return str(v)
else:
return '"%s"' % encoding.jsonescape(v)
class jsonformatter(baseformatter):
def __init__(self, ui, topic, opts):
baseformatter.__init__(self, ui, topic, opts)
self._ui.write("[")
self._ui._first = True
def _showitem(self):
if self._ui._first:
self._ui._first = False
else:
self._ui.write(",")
self._ui.write("\n {\n")
first = True
for k, v in sorted(self._item.items()):
if first:
first = False
else:
self._ui.write(",\n")
self._ui.write(' "%s": %s' % (k, _jsonifyobj(v)))
self._ui.write("\n }")
def end(self):
baseformatter.end(self)
self._ui.write("\n]\n")
class templateformatter(baseformatter):
def __init__(self, ui, topic, opts):
baseformatter.__init__(self, ui, topic, opts)
self._topic = topic
self._t = gettemplater(ui, topic, opts.get('template', ''))
def _showitem(self):
g = self._t(self._topic, **self._item)
self._ui.write(templater.stringify(g))
def lookuptemplate(ui, topic, tmpl):
# looks like a literal template?
if '{' in tmpl:
return tmpl, None
# perhaps a stock style?
if not os.path.split(tmpl)[0]:
mapname = (templater.templatepath('map-cmdline.' + tmpl)
or templater.templatepath(tmpl))
if mapname and os.path.isfile(mapname):
return None, mapname
# perhaps it's a reference to [templates]
t = ui.config('templates', tmpl)
if t:
try:
tmpl = templater.unquotestring(t)
except SyntaxError:
tmpl = t
return tmpl, None
if tmpl == 'list':
ui.write(_("available styles: %s\n") % templater.stylelist())
raise util.Abort(_("specify a template"))
# perhaps it's a path to a map or a template
if ('/' in tmpl or '\\' in tmpl) and os.path.isfile(tmpl):
# is it a mapfile for a style?
if os.path.basename(tmpl).startswith("map-"):
return None, os.path.realpath(tmpl)
tmpl = open(tmpl).read()
return tmpl, None
# constant string?
return tmpl, None
def gettemplater(ui, topic, spec):
tmpl, mapfile = lookuptemplate(ui, topic, spec)
t = templater.templater(mapfile, {})
if tmpl:
t.cache[topic] = tmpl
return t
def formatter(ui, topic, opts):
template = opts.get("template", "")
if template == "json":
return jsonformatter(ui, topic, opts)
elif template == "pickle":
return pickleformatter(ui, topic, opts)
elif template == "debug":
return debugformatter(ui, topic, opts)
elif template != "":
return templateformatter(ui, topic, opts)
# developer config: ui.formatdebug
elif ui.configbool('ui', 'formatdebug'):
return debugformatter(ui, topic, opts)
# deprecated config: ui.formatjson
elif ui.configbool('ui', 'formatjson'):
return jsonformatter(ui, topic, opts)
return plainformatter(ui, topic, opts)