##// END OF EJS Templates
bdiff: replace hash algorithm...
bdiff: replace hash algorithm This patch replaces lyhash with the hash algorithm used by diffutils. The algorithm has its origins in Git commit 2e9d1410, which is all the way back from 1992. The license header in the code at that revision in GPL v2. I have not performed an extensive analysis of the distribution (and therefore buckets) of hash output. However, `hg perfbdiff` gives some clear wins. I'd like to think that if it is good enough for diffutils it is good enough for us? From the mozilla-unified repository: $ perfbdiff -m 3041e4d59df2 ! wall 0.053271 comb 0.060000 user 0.060000 sys 0.000000 (best of 100) ! wall 0.035827 comb 0.040000 user 0.040000 sys 0.000000 (best of 100) $ perfbdiff 0e9928989e9c --alldata --count 100 ! wall 6.204277 comb 6.200000 user 6.200000 sys 0.000000 (best of 3) ! wall 4.309710 comb 4.300000 user 4.300000 sys 0.000000 (best of 3) From the hg repo: $ perfbdiff 35000 --alldata --count 1000 ! wall 0.660358 comb 0.660000 user 0.660000 sys 0.000000 (best of 15) ! wall 0.534092 comb 0.530000 user 0.530000 sys 0.000000 (best of 19) Looking at the generated assembly and statistical profiler output from the kernel level, I believe there is room to make this function even faster. Namely, we're still consuming data character by character instead of at the word level. This translates to more loop iterations and more instructions. At this juncture though, the real performance killer is that we're hashing every line. We should get a significant speedup if we change the algorithm to find the longest prefix, longest suffix, treat those as single "lines" and then only do the line splitting and hashing on the parts that are different. That will require a lot of C code, however. I'm optimistic this approach could result in a ~2x speedup.

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cvs.py
296 lines | 10.5 KiB | text/x-python | PythonLexer
# cvs.py: CVS conversion code inspired by hg-cvs-import and git-cvsimport
#
# Copyright 2005-2009 Matt Mackall <mpm@selenic.com> and others
#
# 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 os
import re
import socket
from mercurial.i18n import _
from mercurial import (
encoding,
error,
util,
)
from . import (
common,
cvsps,
)
stringio = util.stringio
checktool = common.checktool
commit = common.commit
converter_source = common.converter_source
makedatetimestamp = common.makedatetimestamp
NoRepo = common.NoRepo
class convert_cvs(converter_source):
def __init__(self, ui, path, revs=None):
super(convert_cvs, self).__init__(ui, path, revs=revs)
cvs = os.path.join(path, "CVS")
if not os.path.exists(cvs):
raise NoRepo(_("%s does not look like a CVS checkout") % path)
checktool('cvs')
self.changeset = None
self.files = {}
self.tags = {}
self.lastbranch = {}
self.socket = None
self.cvsroot = open(os.path.join(cvs, "Root")).read()[:-1]
self.cvsrepo = open(os.path.join(cvs, "Repository")).read()[:-1]
self.encoding = encoding.encoding
self._connect()
def _parse(self):
if self.changeset is not None:
return
self.changeset = {}
maxrev = 0
if self.revs:
if len(self.revs) > 1:
raise error.Abort(_('cvs source does not support specifying '
'multiple revs'))
# TODO: handle tags
try:
# patchset number?
maxrev = int(self.revs[0])
except ValueError:
raise error.Abort(_('revision %s is not a patchset number')
% self.revs[0])
d = os.getcwd()
try:
os.chdir(self.path)
id = None
cache = 'update'
if not self.ui.configbool('convert', 'cvsps.cache', True):
cache = None
db = cvsps.createlog(self.ui, cache=cache)
db = cvsps.createchangeset(self.ui, db,
fuzz=int(self.ui.config('convert', 'cvsps.fuzz', 60)),
mergeto=self.ui.config('convert', 'cvsps.mergeto', None),
mergefrom=self.ui.config('convert', 'cvsps.mergefrom', None))
for cs in db:
if maxrev and cs.id > maxrev:
break
id = str(cs.id)
cs.author = self.recode(cs.author)
self.lastbranch[cs.branch] = id
cs.comment = self.recode(cs.comment)
if self.ui.configbool('convert', 'localtimezone'):
cs.date = makedatetimestamp(cs.date[0])
date = util.datestr(cs.date, '%Y-%m-%d %H:%M:%S %1%2')
self.tags.update(dict.fromkeys(cs.tags, id))
files = {}
for f in cs.entries:
files[f.file] = "%s%s" % ('.'.join([str(x)
for x in f.revision]),
['', '(DEAD)'][f.dead])
# add current commit to set
c = commit(author=cs.author, date=date,
parents=[str(p.id) for p in cs.parents],
desc=cs.comment, branch=cs.branch or '')
self.changeset[id] = c
self.files[id] = files
self.heads = self.lastbranch.values()
finally:
os.chdir(d)
def _connect(self):
root = self.cvsroot
conntype = None
user, host = None, None
cmd = ['cvs', 'server']
self.ui.status(_("connecting to %s\n") % root)
if root.startswith(":pserver:"):
root = root[9:]
m = re.match(r'(?:(.*?)(?::(.*?))?@)?([^:\/]*)(?::(\d*))?(.*)',
root)
if m:
conntype = "pserver"
user, passw, serv, port, root = m.groups()
if not user:
user = "anonymous"
if not port:
port = 2401
else:
port = int(port)
format0 = ":pserver:%s@%s:%s" % (user, serv, root)
format1 = ":pserver:%s@%s:%d%s" % (user, serv, port, root)
if not passw:
passw = "A"
cvspass = os.path.expanduser("~/.cvspass")
try:
pf = open(cvspass)
for line in pf.read().splitlines():
part1, part2 = line.split(' ', 1)
# /1 :pserver:user@example.com:2401/cvsroot/foo
# Ah<Z
if part1 == '/1':
part1, part2 = part2.split(' ', 1)
format = format1
# :pserver:user@example.com:/cvsroot/foo Ah<Z
else:
format = format0
if part1 == format:
passw = part2
break
pf.close()
except IOError as inst:
if inst.errno != errno.ENOENT:
if not getattr(inst, 'filename', None):
inst.filename = cvspass
raise
sck = socket.socket()
sck.connect((serv, port))
sck.send("\n".join(["BEGIN AUTH REQUEST", root, user, passw,
"END AUTH REQUEST", ""]))
if sck.recv(128) != "I LOVE YOU\n":
raise error.Abort(_("CVS pserver authentication failed"))
self.writep = self.readp = sck.makefile('r+')
if not conntype and root.startswith(":local:"):
conntype = "local"
root = root[7:]
if not conntype:
# :ext:user@host/home/user/path/to/cvsroot
if root.startswith(":ext:"):
root = root[5:]
m = re.match(r'(?:([^@:/]+)@)?([^:/]+):?(.*)', root)
# Do not take Windows path "c:\foo\bar" for a connection strings
if os.path.isdir(root) or not m:
conntype = "local"
else:
conntype = "rsh"
user, host, root = m.group(1), m.group(2), m.group(3)
if conntype != "pserver":
if conntype == "rsh":
rsh = os.environ.get("CVS_RSH") or "ssh"
if user:
cmd = [rsh, '-l', user, host] + cmd
else:
cmd = [rsh, host] + cmd
# popen2 does not support argument lists under Windows
cmd = [util.shellquote(arg) for arg in cmd]
cmd = util.quotecommand(' '.join(cmd))
self.writep, self.readp = util.popen2(cmd)
self.realroot = root
self.writep.write("Root %s\n" % root)
self.writep.write("Valid-responses ok error Valid-requests Mode"
" M Mbinary E Checked-in Created Updated"
" Merged Removed\n")
self.writep.write("valid-requests\n")
self.writep.flush()
r = self.readp.readline()
if not r.startswith("Valid-requests"):
raise error.Abort(_('unexpected response from CVS server '
'(expected "Valid-requests", but got %r)')
% r)
if "UseUnchanged" in r:
self.writep.write("UseUnchanged\n")
self.writep.flush()
r = self.readp.readline()
def getheads(self):
self._parse()
return self.heads
def getfile(self, name, rev):
def chunkedread(fp, count):
# file-objects returned by socket.makefile() do not handle
# large read() requests very well.
chunksize = 65536
output = stringio()
while count > 0:
data = fp.read(min(count, chunksize))
if not data:
raise error.Abort(_("%d bytes missing from remote file")
% count)
count -= len(data)
output.write(data)
return output.getvalue()
self._parse()
if rev.endswith("(DEAD)"):
return None, None
args = ("-N -P -kk -r %s --" % rev).split()
args.append(self.cvsrepo + '/' + name)
for x in args:
self.writep.write("Argument %s\n" % x)
self.writep.write("Directory .\n%s\nco\n" % self.realroot)
self.writep.flush()
data = ""
mode = None
while True:
line = self.readp.readline()
if line.startswith("Created ") or line.startswith("Updated "):
self.readp.readline() # path
self.readp.readline() # entries
mode = self.readp.readline()[:-1]
count = int(self.readp.readline()[:-1])
data = chunkedread(self.readp, count)
elif line.startswith(" "):
data += line[1:]
elif line.startswith("M "):
pass
elif line.startswith("Mbinary "):
count = int(self.readp.readline()[:-1])
data = chunkedread(self.readp, count)
else:
if line == "ok\n":
if mode is None:
raise error.Abort(_('malformed response from CVS'))
return (data, "x" in mode and "x" or "")
elif line.startswith("E "):
self.ui.warn(_("cvs server: %s\n") % line[2:])
elif line.startswith("Remove"):
self.readp.readline()
else:
raise error.Abort(_("unknown CVS response: %s") % line)
def getchanges(self, rev, full):
if full:
raise error.Abort(_("convert from cvs does not support --full"))
self._parse()
return sorted(self.files[rev].iteritems()), {}, set()
def getcommit(self, rev):
self._parse()
return self.changeset[rev]
def gettags(self):
self._parse()
return self.tags
def getchangedfiles(self, rev, i):
self._parse()
return sorted(self.files[rev])