Mercurial > hg
view mercurial/archival.py @ 30212:260af19891f2
changegroup: increase write buffer size to 128k
By default, Python defers to the operating system for choosing the
default buffer size on opened files. On my Linux machine, the default
is 4k, which is really small for 2016.
This patch bumps the write buffer size when writing
changegroups/bundles to 128k. This matches the 128k read buffer
we already use on revlogs.
It's worth noting that this only impacts when writing to an explicit
file (such as during `hg bundle`). Buffers when writing to bundle
files via the repo vfs or to a temporary file are not impacted.
When producing a none-v2 bundle file of the mozilla-unified repository,
this change caused the number of write() system calls to drop from
952,449 to 29,788. After this change, the most frequent system
calls are fstat(), read(), lseek(), and open(). There were
2,523,672 system calls after this patch (so a net decrease of
~950k is statistically significant).
This change shows no performance change on my system. But I have a
high-end system with a fast SSD. It is quite possible this change
will have a significant impact on network file systems, where
extra network round trips due to excessive I/O system calls could
introduce significant latency.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Sun, 16 Oct 2016 13:35:23 -0700 |
parents | 31a6d5e14508 |
children | 798bcb1274dd |
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# archival.py - revision archival for mercurial # # 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 gzip import os import struct import tarfile import time import zipfile import zlib from .i18n import _ from . import ( cmdutil, encoding, error, match as matchmod, scmutil, util, ) stringio = util.stringio # from unzip source code: _UNX_IFREG = 0x8000 _UNX_IFLNK = 0xa000 def tidyprefix(dest, kind, prefix): '''choose prefix to use for names in archive. make sure prefix is safe for consumers.''' if prefix: prefix = util.normpath(prefix) else: if not isinstance(dest, str): raise ValueError('dest must be string if no prefix') prefix = os.path.basename(dest) lower = prefix.lower() for sfx in exts.get(kind, []): if lower.endswith(sfx): prefix = prefix[:-len(sfx)] break lpfx = os.path.normpath(util.localpath(prefix)) prefix = util.pconvert(lpfx) if not prefix.endswith('/'): prefix += '/' # Drop the leading '.' path component if present, so Windows can read the # zip files (issue4634) if prefix.startswith('./'): prefix = prefix[2:] if prefix.startswith('../') or os.path.isabs(lpfx) or '/../' in prefix: raise error.Abort(_('archive prefix contains illegal components')) return prefix exts = { 'tar': ['.tar'], 'tbz2': ['.tbz2', '.tar.bz2'], 'tgz': ['.tgz', '.tar.gz'], 'zip': ['.zip'], } def guesskind(dest): for kind, extensions in exts.iteritems(): if any(dest.endswith(ext) for ext in extensions): return kind return None def _rootctx(repo): # repo[0] may be hidden for rev in repo: return repo[rev] return repo['null'] def buildmetadata(ctx): '''build content of .hg_archival.txt''' repo = ctx.repo() hex = ctx.hex() if ctx.rev() is None: hex = ctx.p1().hex() if ctx.dirty(): hex += '+' base = 'repo: %s\nnode: %s\nbranch: %s\n' % ( _rootctx(repo).hex(), hex, encoding.fromlocal(ctx.branch())) tags = ''.join('tag: %s\n' % t for t in ctx.tags() if repo.tagtype(t) == 'global') if not tags: repo.ui.pushbuffer() opts = {'template': '{latesttag}\n{latesttagdistance}\n' '{changessincelatesttag}', 'style': '', 'patch': None, 'git': None} cmdutil.show_changeset(repo.ui, repo, opts).show(ctx) ltags, dist, changessince = repo.ui.popbuffer().split('\n') ltags = ltags.split(':') tags = ''.join('latesttag: %s\n' % t for t in ltags) tags += 'latesttagdistance: %s\n' % dist tags += 'changessincelatesttag: %s\n' % changessince return base + tags class tarit(object): '''write archive to tar file or stream. can write uncompressed, or compress with gzip or bzip2.''' class GzipFileWithTime(gzip.GzipFile): def __init__(self, *args, **kw): timestamp = None if 'timestamp' in kw: timestamp = kw.pop('timestamp') if timestamp is None: self.timestamp = time.time() else: self.timestamp = timestamp gzip.GzipFile.__init__(self, *args, **kw) def _write_gzip_header(self): self.fileobj.write('\037\213') # magic header self.fileobj.write('\010') # compression method fname = self.name if fname and fname.endswith('.gz'): fname = fname[:-3] flags = 0 if fname: flags = gzip.FNAME self.fileobj.write(chr(flags)) gzip.write32u(self.fileobj, long(self.timestamp)) self.fileobj.write('\002') self.fileobj.write('\377') if fname: self.fileobj.write(fname + '\000') def __init__(self, dest, mtime, kind=''): self.mtime = mtime self.fileobj = None def taropen(name, mode, fileobj=None): if kind == 'gz': mode = mode[0] if not fileobj: fileobj = open(name, mode + 'b') gzfileobj = self.GzipFileWithTime(name, mode + 'b', zlib.Z_BEST_COMPRESSION, fileobj, timestamp=mtime) self.fileobj = gzfileobj return tarfile.TarFile.taropen(name, mode, gzfileobj) else: return tarfile.open(name, mode + kind, fileobj) if isinstance(dest, str): self.z = taropen(dest, mode='w:') else: # Python 2.5-2.5.1 have a regression that requires a name arg self.z = taropen(name='', mode='w|', fileobj=dest) def addfile(self, name, mode, islink, data): i = tarfile.TarInfo(name) i.mtime = self.mtime i.size = len(data) if islink: i.type = tarfile.SYMTYPE i.mode = 0o777 i.linkname = data data = None i.size = 0 else: i.mode = mode data = stringio(data) self.z.addfile(i, data) def done(self): self.z.close() if self.fileobj: self.fileobj.close() class tellable(object): '''provide tell method for zipfile.ZipFile when writing to http response file object.''' def __init__(self, fp): self.fp = fp self.offset = 0 def __getattr__(self, key): return getattr(self.fp, key) def write(self, s): self.fp.write(s) self.offset += len(s) def tell(self): return self.offset class zipit(object): '''write archive to zip file or stream. can write uncompressed, or compressed with deflate.''' def __init__(self, dest, mtime, compress=True): if not isinstance(dest, str): try: dest.tell() except (AttributeError, IOError): dest = tellable(dest) self.z = zipfile.ZipFile(dest, 'w', compress and zipfile.ZIP_DEFLATED or zipfile.ZIP_STORED) # Python's zipfile module emits deprecation warnings if we try # to store files with a date before 1980. epoch = 315532800 # calendar.timegm((1980, 1, 1, 0, 0, 0, 1, 1, 0)) if mtime < epoch: mtime = epoch self.mtime = mtime self.date_time = time.gmtime(mtime)[:6] def addfile(self, name, mode, islink, data): i = zipfile.ZipInfo(name, self.date_time) i.compress_type = self.z.compression # unzip will not honor unix file modes unless file creator is # set to unix (id 3). i.create_system = 3 ftype = _UNX_IFREG if islink: mode = 0o777 ftype = _UNX_IFLNK i.external_attr = (mode | ftype) << 16 # add "extended-timestamp" extra block, because zip archives # without this will be extracted with unexpected timestamp, # if TZ is not configured as GMT i.extra += struct.pack('<hhBl', 0x5455, # block type: "extended-timestamp" 1 + 4, # size of this block 1, # "modification time is present" int(self.mtime)) # last modification (UTC) self.z.writestr(i, data) def done(self): self.z.close() class fileit(object): '''write archive as files in directory.''' def __init__(self, name, mtime): self.basedir = name self.opener = scmutil.opener(self.basedir) def addfile(self, name, mode, islink, data): if islink: self.opener.symlink(data, name) return f = self.opener(name, "w", atomictemp=True) f.write(data) f.close() destfile = os.path.join(self.basedir, name) os.chmod(destfile, mode) def done(self): pass archivers = { 'files': fileit, 'tar': tarit, 'tbz2': lambda name, mtime: tarit(name, mtime, 'bz2'), 'tgz': lambda name, mtime: tarit(name, mtime, 'gz'), 'uzip': lambda name, mtime: zipit(name, mtime, False), 'zip': zipit, } def archive(repo, dest, node, kind, decode=True, matchfn=None, prefix='', mtime=None, subrepos=False): '''create archive of repo as it was at node. dest can be name of directory, name of archive file, or file object to write archive to. kind is type of archive to create. decode tells whether to put files through decode filters from hgrc. matchfn is function to filter names of files to write to archive. prefix is name of path to put before every archive member.''' if kind == 'files': if prefix: raise error.Abort(_('cannot give prefix when archiving to files')) else: prefix = tidyprefix(dest, kind, prefix) def write(name, mode, islink, getdata): data = getdata() if decode: data = repo.wwritedata(name, data) archiver.addfile(prefix + name, mode, islink, data) if kind not in archivers: raise error.Abort(_("unknown archive type '%s'") % kind) ctx = repo[node] archiver = archivers[kind](dest, mtime or ctx.date()[0]) if repo.ui.configbool("ui", "archivemeta", True): name = '.hg_archival.txt' if not matchfn or matchfn(name): write(name, 0o644, False, lambda: buildmetadata(ctx)) if matchfn: files = [f for f in ctx.manifest().keys() if matchfn(f)] else: files = ctx.manifest().keys() total = len(files) if total: files.sort() repo.ui.progress(_('archiving'), 0, unit=_('files'), total=total) for i, f in enumerate(files): ff = ctx.flags(f) write(f, 'x' in ff and 0o755 or 0o644, 'l' in ff, ctx[f].data) repo.ui.progress(_('archiving'), i + 1, item=f, unit=_('files'), total=total) repo.ui.progress(_('archiving'), None) if subrepos: for subpath in sorted(ctx.substate): sub = ctx.workingsub(subpath) submatch = matchmod.subdirmatcher(subpath, matchfn) total += sub.archive(archiver, prefix, submatch) if total == 0: raise error.Abort(_('no files match the archive pattern')) archiver.done() return total