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.
# httppeer.py - HTTP repository proxy classes for mercurial
#
# Copyright 2005, 2006 Matt Mackall <mpm@selenic.com>
# Copyright 2006 Vadim Gelfer <vadim.gelfer@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
import errno
import httplib
import os
import socket
import tempfile
import urllib
import urllib2
import zlib
from .i18n import _
from .node import nullid
from . import (
changegroup,
error,
httpconnection,
statichttprepo,
url,
util,
wireproto,
)
def zgenerator(f):
zd = zlib.decompressobj()
try:
for chunk in util.filechunkiter(f):
while chunk:
yield zd.decompress(chunk, 2**18)
chunk = zd.unconsumed_tail
except httplib.HTTPException:
raise IOError(None, _('connection ended unexpectedly'))
yield zd.flush()
class httppeer(wireproto.wirepeer):
def __init__(self, ui, path):
self.path = path
self.caps = None
self.handler = None
self.urlopener = None
self.requestbuilder = None
u = util.url(path)
if u.query or u.fragment:
raise util.Abort(_('unsupported URL component: "%s"') %
(u.query or u.fragment))
# urllib cannot handle URLs with embedded user or passwd
self._url, authinfo = u.authinfo()
self.ui = ui
self.ui.debug('using %s\n' % self._url)
self.urlopener = url.opener(ui, authinfo)
self.requestbuilder = urllib2.Request
def __del__(self):
if self.urlopener:
for h in self.urlopener.handlers:
h.close()
getattr(h, "close_all", lambda : None)()
def url(self):
return self.path
# look up capabilities only when needed
def _fetchcaps(self):
self.caps = set(self._call('capabilities').split())
def _capabilities(self):
if self.caps is None:
try:
self._fetchcaps()
except error.RepoError:
self.caps = set()
self.ui.debug('capabilities: %s\n' %
(' '.join(self.caps or ['none'])))
return self.caps
def lock(self):
raise util.Abort(_('operation not supported over http'))
def _callstream(self, cmd, **args):
if cmd == 'pushkey':
args['data'] = ''
data = args.pop('data', None)
size = 0
if util.safehasattr(data, 'length'):
size = data.length
elif data is not None:
size = len(data)
headers = args.pop('headers', {})
if data is not None and 'Content-Type' not in headers:
headers['Content-Type'] = 'application/mercurial-0.1'
if size and self.ui.configbool('ui', 'usehttp2', False):
headers['Expect'] = '100-Continue'
headers['X-HgHttp2'] = '1'
self.ui.debug("sending %s command\n" % cmd)
q = [('cmd', cmd)]
headersize = 0
if len(args) > 0:
httpheader = self.capable('httpheader')
if httpheader:
headersize = int(httpheader.split(',')[0])
if headersize > 0:
# The headers can typically carry more data than the URL.
encargs = urllib.urlencode(sorted(args.items()))
headerfmt = 'X-HgArg-%s'
contentlen = headersize - len(headerfmt % '000' + ': \r\n')
headernum = 0
for i in xrange(0, len(encargs), contentlen):
headernum += 1
header = headerfmt % str(headernum)
headers[header] = encargs[i:i + contentlen]
varyheaders = [headerfmt % str(h) for h in range(1, headernum + 1)]
headers['Vary'] = ','.join(varyheaders)
else:
q += sorted(args.items())
qs = '?%s' % urllib.urlencode(q)
cu = "%s%s" % (self._url, qs)
req = self.requestbuilder(cu, data, headers)
if data is not None:
self.ui.debug("sending %s bytes\n" % size)
req.add_unredirected_header('Content-Length', '%d' % size)
try:
resp = self.urlopener.open(req)
except urllib2.HTTPError as inst:
if inst.code == 401:
raise util.Abort(_('authorization failed'))
raise
except httplib.HTTPException as inst:
self.ui.debug('http error while sending %s command\n' % cmd)
self.ui.traceback()
raise IOError(None, inst)
except IndexError:
# this only happens with Python 2.3, later versions raise URLError
raise util.Abort(_('http error, possibly caused by proxy setting'))
# record the url we got redirected to
resp_url = resp.geturl()
if resp_url.endswith(qs):
resp_url = resp_url[:-len(qs)]
if self._url.rstrip('/') != resp_url.rstrip('/'):
if not self.ui.quiet:
self.ui.warn(_('real URL is %s\n') % resp_url)
self._url = resp_url
try:
proto = resp.getheader('content-type')
except AttributeError:
proto = resp.headers.get('content-type', '')
safeurl = util.hidepassword(self._url)
if proto.startswith('application/hg-error'):
raise error.OutOfBandError(resp.read())
# accept old "text/plain" and "application/hg-changegroup" for now
if not (proto.startswith('application/mercurial-') or
(proto.startswith('text/plain')
and not resp.headers.get('content-length')) or
proto.startswith('application/hg-changegroup')):
self.ui.debug("requested URL: '%s'\n" % util.hidepassword(cu))
raise error.RepoError(
_("'%s' does not appear to be an hg repository:\n"
"---%%<--- (%s)\n%s\n---%%<---\n")
% (safeurl, proto or 'no content-type', resp.read(1024)))
if proto.startswith('application/mercurial-'):
try:
version = proto.split('-', 1)[1]
version_info = tuple([int(n) for n in version.split('.')])
except ValueError:
raise error.RepoError(_("'%s' sent a broken Content-Type "
"header (%s)") % (safeurl, proto))
if version_info > (0, 1):
raise error.RepoError(_("'%s' uses newer protocol %s") %
(safeurl, version))
return resp
def _call(self, cmd, **args):
fp = self._callstream(cmd, **args)
try:
return fp.read()
finally:
# if using keepalive, allow connection to be reused
fp.close()
def _callpush(self, cmd, cg, **args):
# have to stream bundle to a temp file because we do not have
# http 1.1 chunked transfer.
types = self.capable('unbundle')
try:
types = types.split(',')
except AttributeError:
# servers older than d1b16a746db6 will send 'unbundle' as a
# boolean capability. They only support headerless/uncompressed
# bundles.
types = [""]
for x in types:
if x in changegroup.bundletypes:
type = x
break
tempname = changegroup.writebundle(self.ui, cg, None, type)
fp = httpconnection.httpsendfile(self.ui, tempname, "rb")
headers = {'Content-Type': 'application/mercurial-0.1'}
try:
r = self._call(cmd, data=fp, headers=headers, **args)
vals = r.split('\n', 1)
if len(vals) < 2:
raise error.ResponseError(_("unexpected response:"), r)
return vals
except socket.error as err:
if err.args[0] in (errno.ECONNRESET, errno.EPIPE):
raise util.Abort(_('push failed: %s') % err.args[1])
raise util.Abort(err.args[1])
finally:
fp.close()
os.unlink(tempname)
def _calltwowaystream(self, cmd, fp, **args):
fh = None
fp_ = None
filename = None
try:
# dump bundle to disk
fd, filename = tempfile.mkstemp(prefix="hg-bundle-", suffix=".hg")
fh = os.fdopen(fd, "wb")
d = fp.read(4096)
while d:
fh.write(d)
d = fp.read(4096)
fh.close()
# start http push
fp_ = httpconnection.httpsendfile(self.ui, filename, "rb")
headers = {'Content-Type': 'application/mercurial-0.1'}
return self._callstream(cmd, data=fp_, headers=headers, **args)
finally:
if fp_ is not None:
fp_.close()
if fh is not None:
fh.close()
os.unlink(filename)
def _callcompressable(self, cmd, **args):
stream = self._callstream(cmd, **args)
return util.chunkbuffer(zgenerator(stream))
def _abort(self, exception):
raise exception
class httpspeer(httppeer):
def __init__(self, ui, path):
if not url.has_https:
raise util.Abort(_('Python support for SSL and HTTPS '
'is not installed'))
httppeer.__init__(self, ui, path)
def instance(ui, path, create):
if create:
raise util.Abort(_('cannot create new http repository'))
try:
if path.startswith('https:'):
inst = httpspeer(ui, path)
else:
inst = httppeer(ui, path)
try:
# Try to do useful work when checking compatibility.
# Usually saves a roundtrip since we want the caps anyway.
inst._fetchcaps()
except error.RepoError:
# No luck, try older compatibility check.
inst.between([(nullid, nullid)])
return inst
except error.RepoError as httpexception:
try:
r = statichttprepo.instance(ui, "static-" + path, create)
ui.note('(falling back to static-http)\n')
return r
except error.RepoError:
raise httpexception # use the original http RepoError instead