Mercurial > hg
view mercurial/pycompat.py @ 42043:1fac9b931d46
compression: introduce a `storage.revlog.zlib.level` configuration
This option control the zlib compression level used when compression revlog
chunk.
This is also a good excuse to pave the way for a similar configuration option
for the zstd compression engine. Having a dedicated option for each compression
algorithm is useful because they don't support the same range of values.
Using a higher zlib compression impact CPU consumption at compression time, but
does not directly affected decompression time. However dealing with small
compressed chunk can directly help decompression and indirectly help other
revlog logic.
I ran some basic test on repositories using different level. I am using the
mercurial, pypy, netbeans and mozilla-central clone from our benchmark suite.
All tested repository use sparse-revlog and got all their delta recomputed.
The different compression level has a small effect on the repository size
(about 10% variation in the total range). My quick analysis is that revlog
mostly store small delta, that are not affected by the compression level much.
So the variation probably mostly comes from better compression of the snapshots
revisions, and snapshot revision only represent a small portion of the
repository content.
I also made some basic timings measurements. The "read" timings are gathered using
simple run of `hg perfrevlogrevisions`, the "write" timings using `hg
perfrevlogwrite` (restricted to the last 5000 revisions for netbeans and
mozilla central). The timings are gathered on a generic machine, (not one of
our performance locked machine), so small variation might not be meaningful.
However large trend remains relevant.
Keep in mind that these numbers are not pure compression/decompression time.
They also involve the full revlog logic. In particular the difference in chunk
size has an impact on the delta chain structure, affecting performance when
writing or reading them.
On read/write performance, the compression level has a bigger impact.
Counter-intuitively, the higher compression levels improve "write" performance
for the large repositories in our tested setting. Maybe because the last 5000
delta chain end up having a very different shape in this specific spot? Or maybe
because of a more general trend of better delta chains thanks to the smaller
chunk and snapshot.
This series does not intend to change the default compression level. However,
these result call for a deeper analysis of this performance difference in the
future.
Full data
=========
repo level .hg/store size 00manifest.d read write
----------------------------------------------------------------
mercurial 1 49,402,813 5,963,475 0.170159 53.250304
mercurial 6 47,197,397 5,875,730 0.182820 56.264320
mercurial 9 47,121,596 5,849,781 0.189219 56.293612
pypy 1 370,830,572 28,462,425 2.679217 460.721984
pypy 6 340,112,317 27,648,747 2.768691 467.537158
pypy 9 338,360,736 27,639,003 2.763495 476.589918
netbeans 1 1,281,847,810 165,495,457 122.477027 520.560316
netbeans 6 1,205,284,353 159,161,207 139.876147 715.930400
netbeans 9 1,197,135,671 155,034,586 141.620281 678.297064
mozilla 1 2,775,497,186 298,527,987 147.867662 751.263721
mozilla 6 2,596,856,420 286,597,671 170.572118 987.056093
mozilla 9 2,587,542,494 287,018,264 163.622338 739.803002
author | Pierre-Yves David <pierre-yves.david@octobus.net> |
---|---|
date | Wed, 27 Mar 2019 18:35:27 +0100 |
parents | 1b49b84d5ed5 |
children | 2cc453284d5c |
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# pycompat.py - portability shim for python 3 # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. """Mercurial portability shim for python 3. This contains aliases to hide python version-specific details from the core. """ from __future__ import absolute_import import getopt import inspect import os import shlex import sys import tempfile ispy3 = (sys.version_info[0] >= 3) ispypy = (r'__pypy__' in sys.builtin_module_names) if not ispy3: import cookielib import cPickle as pickle import httplib import Queue as queue import SocketServer as socketserver import xmlrpclib from .thirdparty.concurrent import futures def future_set_exception_info(f, exc_info): f.set_exception_info(*exc_info) else: import concurrent.futures as futures import http.cookiejar as cookielib import http.client as httplib import pickle import queue as queue import socketserver import xmlrpc.client as xmlrpclib def future_set_exception_info(f, exc_info): f.set_exception(exc_info[0]) def identity(a): return a def _rapply(f, xs): if xs is None: # assume None means non-value of optional data return xs if isinstance(xs, (list, set, tuple)): return type(xs)(_rapply(f, x) for x in xs) if isinstance(xs, dict): return type(xs)((_rapply(f, k), _rapply(f, v)) for k, v in xs.items()) return f(xs) def rapply(f, xs): """Apply function recursively to every item preserving the data structure >>> def f(x): ... return 'f(%s)' % x >>> rapply(f, None) is None True >>> rapply(f, 'a') 'f(a)' >>> rapply(f, {'a'}) == {'f(a)'} True >>> rapply(f, ['a', 'b', None, {'c': 'd'}, []]) ['f(a)', 'f(b)', None, {'f(c)': 'f(d)'}, []] >>> xs = [object()] >>> rapply(identity, xs) is xs True """ if f is identity: # fast path mainly for py2 return xs return _rapply(f, xs) if ispy3: import builtins import functools import io import struct fsencode = os.fsencode fsdecode = os.fsdecode oscurdir = os.curdir.encode('ascii') oslinesep = os.linesep.encode('ascii') osname = os.name.encode('ascii') ospathsep = os.pathsep.encode('ascii') ospardir = os.pardir.encode('ascii') ossep = os.sep.encode('ascii') osaltsep = os.altsep if osaltsep: osaltsep = osaltsep.encode('ascii') sysplatform = sys.platform.encode('ascii') sysexecutable = sys.executable if sysexecutable: sysexecutable = os.fsencode(sysexecutable) bytesio = io.BytesIO # TODO deprecate stringio name, as it is a lie on Python 3. stringio = bytesio def maplist(*args): return list(map(*args)) def rangelist(*args): return list(range(*args)) def ziplist(*args): return list(zip(*args)) rawinput = input getargspec = inspect.getfullargspec long = int # TODO: .buffer might not exist if std streams were replaced; we'll need # a silly wrapper to make a bytes stream backed by a unicode one. stdin = sys.stdin.buffer stdout = sys.stdout.buffer stderr = sys.stderr.buffer # Since Python 3 converts argv to wchar_t type by Py_DecodeLocale() on Unix, # we can use os.fsencode() to get back bytes argv. # # https://hg.python.org/cpython/file/v3.5.1/Programs/python.c#l55 # # TODO: On Windows, the native argv is wchar_t, so we'll need a different # workaround to simulate the Python 2 (i.e. ANSI Win32 API) behavior. if getattr(sys, 'argv', None) is not None: sysargv = list(map(os.fsencode, sys.argv)) bytechr = struct.Struct(r'>B').pack byterepr = b'%r'.__mod__ class bytestr(bytes): """A bytes which mostly acts as a Python 2 str >>> bytestr(), bytestr(bytearray(b'foo')), bytestr(u'ascii'), bytestr(1) ('', 'foo', 'ascii', '1') >>> s = bytestr(b'foo') >>> assert s is bytestr(s) __bytes__() should be called if provided: >>> class bytesable(object): ... def __bytes__(self): ... return b'bytes' >>> bytestr(bytesable()) 'bytes' There's no implicit conversion from non-ascii str as its encoding is unknown: >>> bytestr(chr(0x80)) # doctest: +ELLIPSIS Traceback (most recent call last): ... UnicodeEncodeError: ... Comparison between bytestr and bytes should work: >>> assert bytestr(b'foo') == b'foo' >>> assert b'foo' == bytestr(b'foo') >>> assert b'f' in bytestr(b'foo') >>> assert bytestr(b'f') in b'foo' Sliced elements should be bytes, not integer: >>> s[1], s[:2] (b'o', b'fo') >>> list(s), list(reversed(s)) ([b'f', b'o', b'o'], [b'o', b'o', b'f']) As bytestr type isn't propagated across operations, you need to cast bytes to bytestr explicitly: >>> s = bytestr(b'foo').upper() >>> t = bytestr(s) >>> s[0], t[0] (70, b'F') Be careful to not pass a bytestr object to a function which expects bytearray-like behavior. >>> t = bytes(t) # cast to bytes >>> assert type(t) is bytes """ def __new__(cls, s=b''): if isinstance(s, bytestr): return s if (not isinstance(s, (bytes, bytearray)) and not hasattr(s, u'__bytes__')): # hasattr-py3-only s = str(s).encode(u'ascii') return bytes.__new__(cls, s) def __getitem__(self, key): s = bytes.__getitem__(self, key) if not isinstance(s, bytes): s = bytechr(s) return s def __iter__(self): return iterbytestr(bytes.__iter__(self)) def __repr__(self): return bytes.__repr__(self)[1:] # drop b'' def iterbytestr(s): """Iterate bytes as if it were a str object of Python 2""" return map(bytechr, s) def maybebytestr(s): """Promote bytes to bytestr""" if isinstance(s, bytes): return bytestr(s) return s def sysbytes(s): """Convert an internal str (e.g. keyword, __doc__) back to bytes This never raises UnicodeEncodeError, but only ASCII characters can be round-trip by sysstr(sysbytes(s)). """ return s.encode(u'utf-8') def sysstr(s): """Return a keyword str to be passed to Python functions such as getattr() and str.encode() This never raises UnicodeDecodeError. Non-ascii characters are considered invalid and mapped to arbitrary but unique code points such that 'sysstr(a) != sysstr(b)' for all 'a != b'. """ if isinstance(s, builtins.str): return s return s.decode(u'latin-1') def strurl(url): """Converts a bytes url back to str""" if isinstance(url, bytes): return url.decode(u'ascii') return url def bytesurl(url): """Converts a str url to bytes by encoding in ascii""" if isinstance(url, str): return url.encode(u'ascii') return url def raisewithtb(exc, tb): """Raise exception with the given traceback""" raise exc.with_traceback(tb) def getdoc(obj): """Get docstring as bytes; may be None so gettext() won't confuse it with _('')""" doc = getattr(obj, u'__doc__', None) if doc is None: return doc return sysbytes(doc) def _wrapattrfunc(f): @functools.wraps(f) def w(object, name, *args): return f(object, sysstr(name), *args) return w # these wrappers are automagically imported by hgloader delattr = _wrapattrfunc(builtins.delattr) getattr = _wrapattrfunc(builtins.getattr) hasattr = _wrapattrfunc(builtins.hasattr) setattr = _wrapattrfunc(builtins.setattr) xrange = builtins.range unicode = str def open(name, mode=b'r', buffering=-1, encoding=None): return builtins.open(name, sysstr(mode), buffering, encoding) safehasattr = _wrapattrfunc(builtins.hasattr) def _getoptbwrapper(orig, args, shortlist, namelist): """ Takes bytes arguments, converts them to unicode, pass them to getopt.getopt(), convert the returned values back to bytes and then return them for Python 3 compatibility as getopt.getopt() don't accepts bytes on Python 3. """ args = [a.decode('latin-1') for a in args] shortlist = shortlist.decode('latin-1') namelist = [a.decode('latin-1') for a in namelist] opts, args = orig(args, shortlist, namelist) opts = [(a[0].encode('latin-1'), a[1].encode('latin-1')) for a in opts] args = [a.encode('latin-1') for a in args] return opts, args def strkwargs(dic): """ Converts the keys of a python dictonary to str i.e. unicodes so that they can be passed as keyword arguments as dictonaries with bytes keys can't be passed as keyword arguments to functions on Python 3. """ dic = dict((k.decode('latin-1'), v) for k, v in dic.iteritems()) return dic def byteskwargs(dic): """ Converts keys of python dictonaries to bytes as they were converted to str to pass that dictonary as a keyword argument on Python 3. """ dic = dict((k.encode('latin-1'), v) for k, v in dic.iteritems()) return dic # TODO: handle shlex.shlex(). def shlexsplit(s, comments=False, posix=True): """ Takes bytes argument, convert it to str i.e. unicodes, pass that into shlex.split(), convert the returned value to bytes and return that for Python 3 compatibility as shelx.split() don't accept bytes on Python 3. """ ret = shlex.split(s.decode('latin-1'), comments, posix) return [a.encode('latin-1') for a in ret] else: import cStringIO xrange = xrange unicode = unicode bytechr = chr byterepr = repr bytestr = str iterbytestr = iter maybebytestr = identity sysbytes = identity sysstr = identity strurl = identity bytesurl = identity # this can't be parsed on Python 3 exec('def raisewithtb(exc, tb):\n' ' raise exc, None, tb\n') def fsencode(filename): """ Partial backport from os.py in Python 3, which only accepts bytes. In Python 2, our paths should only ever be bytes, a unicode path indicates a bug. """ if isinstance(filename, str): return filename else: raise TypeError( r"expect str, not %s" % type(filename).__name__) # In Python 2, fsdecode() has a very chance to receive bytes. So it's # better not to touch Python 2 part as it's already working fine. fsdecode = identity def getdoc(obj): return getattr(obj, '__doc__', None) _notset = object() def safehasattr(thing, attr): return getattr(thing, attr, _notset) is not _notset def _getoptbwrapper(orig, args, shortlist, namelist): return orig(args, shortlist, namelist) strkwargs = identity byteskwargs = identity oscurdir = os.curdir oslinesep = os.linesep osname = os.name ospathsep = os.pathsep ospardir = os.pardir ossep = os.sep osaltsep = os.altsep long = long stdin = sys.stdin stdout = sys.stdout stderr = sys.stderr if getattr(sys, 'argv', None) is not None: sysargv = sys.argv sysplatform = sys.platform sysexecutable = sys.executable shlexsplit = shlex.split bytesio = cStringIO.StringIO stringio = bytesio maplist = map rangelist = range ziplist = zip rawinput = raw_input getargspec = inspect.getargspec isjython = sysplatform.startswith(b'java') isdarwin = sysplatform.startswith(b'darwin') islinux = sysplatform.startswith(b'linux') isposix = osname == b'posix' iswindows = osname == b'nt' def getoptb(args, shortlist, namelist): return _getoptbwrapper(getopt.getopt, args, shortlist, namelist) def gnugetoptb(args, shortlist, namelist): return _getoptbwrapper(getopt.gnu_getopt, args, shortlist, namelist) def mkdtemp(suffix=b'', prefix=b'tmp', dir=None): return tempfile.mkdtemp(suffix, prefix, dir) # text=True is not supported; use util.from/tonativeeol() instead def mkstemp(suffix=b'', prefix=b'tmp', dir=None): return tempfile.mkstemp(suffix, prefix, dir) # mode must include 'b'ytes as encoding= is not supported def namedtempfile(mode=b'w+b', bufsize=-1, suffix=b'', prefix=b'tmp', dir=None, delete=True): mode = sysstr(mode) assert r'b' in mode return tempfile.NamedTemporaryFile(mode, bufsize, suffix=suffix, prefix=prefix, dir=dir, delete=delete)