Mercurial > hg
view mercurial/changelog.py @ 30451:94ca0e13d1fc
perf: add command for measuring revlog chunk operations
Upcoming commits will teach revlogs to leverage the new compression
engine API so that new compression formats can more easily be
leveraged in revlogs. We want to be sure this refactoring doesn't
regress performance. So this commit introduces "perfrevchunks" to
explicitly test performance of reading, decompressing, and
recompressing revlog chunks.
Here is output when run on the mozilla-unified repo:
$ hg perfrevlogchunks -c
! read
! wall 0.346603 comb 0.350000 user 0.340000 sys 0.010000 (best of 28)
! read w/ reused fd
! wall 0.337707 comb 0.340000 user 0.320000 sys 0.020000 (best of 30)
! read batch
! wall 0.013206 comb 0.020000 user 0.000000 sys 0.020000 (best of 221)
! read batch w/ reused fd
! wall 0.013259 comb 0.030000 user 0.010000 sys 0.020000 (best of 222)
! chunk
! wall 1.909939 comb 1.910000 user 1.900000 sys 0.010000 (best of 6)
! chunk batch
! wall 1.750677 comb 1.760000 user 1.740000 sys 0.020000 (best of 6)
! compress
! wall 5.668004 comb 5.670000 user 5.670000 sys 0.000000 (best of 3)
$ hg perfrevlogchunks -m
! read
! wall 0.365834 comb 0.370000 user 0.350000 sys 0.020000 (best of 26)
! read w/ reused fd
! wall 0.350160 comb 0.350000 user 0.320000 sys 0.030000 (best of 28)
! read batch
! wall 0.024777 comb 0.020000 user 0.000000 sys 0.020000 (best of 119)
! read batch w/ reused fd
! wall 0.024895 comb 0.030000 user 0.000000 sys 0.030000 (best of 118)
! chunk
! wall 2.514061 comb 2.520000 user 2.480000 sys 0.040000 (best of 4)
! chunk batch
! wall 2.380788 comb 2.380000 user 2.360000 sys 0.020000 (best of 5)
! compress
! wall 9.815297 comb 9.820000 user 9.820000 sys 0.000000 (best of 3)
We already see some interesting data, such as how much slower
non-batched chunk reading is and that zlib compression appears to be
>2x slower than decompression.
I didn't have the data when I wrote this commit message, but I ran this
on Mozilla's NFS-based Mercurial server and the time for reading with a
reused file descriptor was faster. So I think it is worth testing both
with and without file descriptor reuse so we can make informed
decisions about recycling file descriptors.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Thu, 17 Nov 2016 20:17:51 -0800 |
parents | 5e4f16874a9f |
children | be520fe3a3e9 |
line wrap: on
line source
# changelog.py - changelog class for mercurial # # Copyright 2005-2007 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 collections from .i18n import _ from .node import ( bin, hex, nullid, ) from . import ( encoding, error, revlog, util, ) _defaultextra = {'branch': 'default'} def _string_escape(text): """ >>> d = {'nl': chr(10), 'bs': chr(92), 'cr': chr(13), 'nul': chr(0)} >>> s = "ab%(nl)scd%(bs)s%(bs)sn%(nul)sab%(cr)scd%(bs)s%(nl)s" % d >>> s 'ab\\ncd\\\\\\\\n\\x00ab\\rcd\\\\\\n' >>> res = _string_escape(s) >>> s == res.decode('string_escape') True """ # subset of the string_escape codec text = text.replace('\\', '\\\\').replace('\n', '\\n').replace('\r', '\\r') return text.replace('\0', '\\0') def decodeextra(text): """ >>> sorted(decodeextra(encodeextra({'foo': 'bar', 'baz': chr(0) + '2'}) ... ).iteritems()) [('baz', '\\x002'), ('branch', 'default'), ('foo', 'bar')] >>> sorted(decodeextra(encodeextra({'foo': 'bar', ... 'baz': chr(92) + chr(0) + '2'}) ... ).iteritems()) [('baz', '\\\\\\x002'), ('branch', 'default'), ('foo', 'bar')] """ extra = _defaultextra.copy() for l in text.split('\0'): if l: if '\\0' in l: # fix up \0 without getting into trouble with \\0 l = l.replace('\\\\', '\\\\\n') l = l.replace('\\0', '\0') l = l.replace('\n', '') k, v = l.decode('string_escape').split(':', 1) extra[k] = v return extra def encodeextra(d): # keys must be sorted to produce a deterministic changelog entry items = [_string_escape('%s:%s' % (k, d[k])) for k in sorted(d)] return "\0".join(items) def stripdesc(desc): """strip trailing whitespace and leading and trailing empty lines""" return '\n'.join([l.rstrip() for l in desc.splitlines()]).strip('\n') class appender(object): '''the changelog index must be updated last on disk, so we use this class to delay writes to it''' def __init__(self, vfs, name, mode, buf): self.data = buf fp = vfs(name, mode) self.fp = fp self.offset = fp.tell() self.size = vfs.fstat(fp).st_size def end(self): return self.size + len("".join(self.data)) def tell(self): return self.offset def flush(self): pass def close(self): self.fp.close() def seek(self, offset, whence=0): '''virtual file offset spans real file and data''' if whence == 0: self.offset = offset elif whence == 1: self.offset += offset elif whence == 2: self.offset = self.end() + offset if self.offset < self.size: self.fp.seek(self.offset) def read(self, count=-1): '''only trick here is reads that span real file and data''' ret = "" if self.offset < self.size: s = self.fp.read(count) ret = s self.offset += len(s) if count > 0: count -= len(s) if count != 0: doff = self.offset - self.size self.data.insert(0, "".join(self.data)) del self.data[1:] s = self.data[0][doff:doff + count] self.offset += len(s) ret += s return ret def write(self, s): self.data.append(str(s)) self.offset += len(s) def _divertopener(opener, target): """build an opener that writes in 'target.a' instead of 'target'""" def _divert(name, mode='r', checkambig=False): if name != target: return opener(name, mode) return opener(name + ".a", mode) return _divert def _delayopener(opener, target, buf): """build an opener that stores chunks in 'buf' instead of 'target'""" def _delay(name, mode='r', checkambig=False): if name != target: return opener(name, mode) return appender(opener, name, mode, buf) return _delay _changelogrevision = collections.namedtuple(u'changelogrevision', (u'manifest', u'user', u'date', u'files', u'description', u'extra')) class changelogrevision(object): """Holds results of a parsed changelog revision. Changelog revisions consist of multiple pieces of data, including the manifest node, user, and date. This object exposes a view into the parsed object. """ __slots__ = ( u'_offsets', u'_text', ) def __new__(cls, text): if not text: return _changelogrevision( manifest=nullid, user='', date=(0, 0), files=[], description='', extra=_defaultextra, ) self = super(changelogrevision, cls).__new__(cls) # We could return here and implement the following as an __init__. # But doing it here is equivalent and saves an extra function call. # format used: # nodeid\n : manifest node in ascii # user\n : user, no \n or \r allowed # time tz extra\n : date (time is int or float, timezone is int) # : extra is metadata, encoded and separated by '\0' # : older versions ignore it # files\n\n : files modified by the cset, no \n or \r allowed # (.*) : comment (free text, ideally utf-8) # # changelog v0 doesn't use extra nl1 = text.index('\n') nl2 = text.index('\n', nl1 + 1) nl3 = text.index('\n', nl2 + 1) # The list of files may be empty. Which means nl3 is the first of the # double newline that precedes the description. if text[nl3 + 1] == '\n': doublenl = nl3 else: doublenl = text.index('\n\n', nl3 + 1) self._offsets = (nl1, nl2, nl3, doublenl) self._text = text return self @property def manifest(self): return bin(self._text[0:self._offsets[0]]) @property def user(self): off = self._offsets return encoding.tolocal(self._text[off[0] + 1:off[1]]) @property def _rawdate(self): off = self._offsets dateextra = self._text[off[1] + 1:off[2]] return dateextra.split(' ', 2)[0:2] @property def _rawextra(self): off = self._offsets dateextra = self._text[off[1] + 1:off[2]] fields = dateextra.split(' ', 2) if len(fields) != 3: return None return fields[2] @property def date(self): raw = self._rawdate time = float(raw[0]) # Various tools did silly things with the timezone. try: timezone = int(raw[1]) except ValueError: timezone = 0 return time, timezone @property def extra(self): raw = self._rawextra if raw is None: return _defaultextra return decodeextra(raw) @property def files(self): off = self._offsets if off[2] == off[3]: return [] return self._text[off[2] + 1:off[3]].split('\n') @property def description(self): return encoding.tolocal(self._text[self._offsets[3] + 2:]) class changelog(revlog.revlog): def __init__(self, opener): revlog.revlog.__init__(self, opener, "00changelog.i", checkambig=True) if self._initempty: # changelogs don't benefit from generaldelta self.version &= ~revlog.REVLOGGENERALDELTA self._generaldelta = False # Delta chains for changelogs tend to be very small because entries # tend to be small and don't delta well with each. So disable delta # chains. self.storedeltachains = False self._realopener = opener self._delayed = False self._delaybuf = None self._divert = False self.filteredrevs = frozenset() def tip(self): """filtered version of revlog.tip""" for i in xrange(len(self) -1, -2, -1): if i not in self.filteredrevs: return self.node(i) def __contains__(self, rev): """filtered version of revlog.__contains__""" return (0 <= rev < len(self) and rev not in self.filteredrevs) def __iter__(self): """filtered version of revlog.__iter__""" if len(self.filteredrevs) == 0: return revlog.revlog.__iter__(self) def filterediter(): for i in xrange(len(self)): if i not in self.filteredrevs: yield i return filterediter() def revs(self, start=0, stop=None): """filtered version of revlog.revs""" for i in super(changelog, self).revs(start, stop): if i not in self.filteredrevs: yield i @util.propertycache def nodemap(self): # XXX need filtering too self.rev(self.node(0)) return self._nodecache def reachableroots(self, minroot, heads, roots, includepath=False): return self.index.reachableroots2(minroot, heads, roots, includepath) def headrevs(self): if self.filteredrevs: try: return self.index.headrevsfiltered(self.filteredrevs) # AttributeError covers non-c-extension environments and # old c extensions without filter handling. except AttributeError: return self._headrevs() return super(changelog, self).headrevs() def strip(self, *args, **kwargs): # XXX make something better than assert # We can't expect proper strip behavior if we are filtered. assert not self.filteredrevs super(changelog, self).strip(*args, **kwargs) def rev(self, node): """filtered version of revlog.rev""" r = super(changelog, self).rev(node) if r in self.filteredrevs: raise error.FilteredLookupError(hex(node), self.indexfile, _('filtered node')) return r def node(self, rev): """filtered version of revlog.node""" if rev in self.filteredrevs: raise error.FilteredIndexError(rev) return super(changelog, self).node(rev) def linkrev(self, rev): """filtered version of revlog.linkrev""" if rev in self.filteredrevs: raise error.FilteredIndexError(rev) return super(changelog, self).linkrev(rev) def parentrevs(self, rev): """filtered version of revlog.parentrevs""" if rev in self.filteredrevs: raise error.FilteredIndexError(rev) return super(changelog, self).parentrevs(rev) def flags(self, rev): """filtered version of revlog.flags""" if rev in self.filteredrevs: raise error.FilteredIndexError(rev) return super(changelog, self).flags(rev) def delayupdate(self, tr): "delay visibility of index updates to other readers" if not self._delayed: if len(self) == 0: self._divert = True if self._realopener.exists(self.indexfile + '.a'): self._realopener.unlink(self.indexfile + '.a') self.opener = _divertopener(self._realopener, self.indexfile) else: self._delaybuf = [] self.opener = _delayopener(self._realopener, self.indexfile, self._delaybuf) self._delayed = True tr.addpending('cl-%i' % id(self), self._writepending) tr.addfinalize('cl-%i' % id(self), self._finalize) def _finalize(self, tr): "finalize index updates" self._delayed = False self.opener = self._realopener # move redirected index data back into place if self._divert: assert not self._delaybuf tmpname = self.indexfile + ".a" nfile = self.opener.open(tmpname) nfile.close() self.opener.rename(tmpname, self.indexfile, checkambig=True) elif self._delaybuf: fp = self.opener(self.indexfile, 'a', checkambig=True) fp.write("".join(self._delaybuf)) fp.close() self._delaybuf = None self._divert = False # split when we're done self.checkinlinesize(tr) def readpending(self, file): """read index data from a "pending" file During a transaction, the actual changeset data is already stored in the main file, but not yet finalized in the on-disk index. Instead, a "pending" index is written by the transaction logic. If this function is running, we are likely in a subprocess invoked in a hook. The subprocess is informed that it is within a transaction and needs to access its content. This function will read all the index data out of the pending file and overwrite the main index.""" if not self.opener.exists(file): return # no pending data for changelog r = revlog.revlog(self.opener, file) self.index = r.index self.nodemap = r.nodemap self._nodecache = r._nodecache self._chunkcache = r._chunkcache def _writepending(self, tr): "create a file containing the unfinalized state for pretxnchangegroup" if self._delaybuf: # make a temporary copy of the index fp1 = self._realopener(self.indexfile) pendingfilename = self.indexfile + ".a" # register as a temp file to ensure cleanup on failure tr.registertmp(pendingfilename) # write existing data fp2 = self._realopener(pendingfilename, "w") fp2.write(fp1.read()) # add pending data fp2.write("".join(self._delaybuf)) fp2.close() # switch modes so finalize can simply rename self._delaybuf = None self._divert = True self.opener = _divertopener(self._realopener, self.indexfile) if self._divert: return True return False def checkinlinesize(self, tr, fp=None): if not self._delayed: revlog.revlog.checkinlinesize(self, tr, fp) def read(self, node): """Obtain data from a parsed changelog revision. Returns a 6-tuple of: - manifest node in binary - author/user as a localstr - date as a 2-tuple of (time, timezone) - list of files - commit message as a localstr - dict of extra metadata Unless you need to access all fields, consider calling ``changelogrevision`` instead, as it is faster for partial object access. """ c = changelogrevision(self.revision(node)) return ( c.manifest, c.user, c.date, c.files, c.description, c.extra ) def changelogrevision(self, nodeorrev): """Obtain a ``changelogrevision`` for a node or revision.""" return changelogrevision(self.revision(nodeorrev)) def readfiles(self, node): """ short version of read that only returns the files modified by the cset """ text = self.revision(node) if not text: return [] last = text.index("\n\n") l = text[:last].split('\n') return l[3:] def add(self, manifest, files, desc, transaction, p1, p2, user, date=None, extra=None): # Convert to UTF-8 encoded bytestrings as the very first # thing: calling any method on a localstr object will turn it # into a str object and the cached UTF-8 string is thus lost. user, desc = encoding.fromlocal(user), encoding.fromlocal(desc) user = user.strip() # An empty username or a username with a "\n" will make the # revision text contain two "\n\n" sequences -> corrupt # repository since read cannot unpack the revision. if not user: raise error.RevlogError(_("empty username")) if "\n" in user: raise error.RevlogError(_("username %s contains a newline") % repr(user)) desc = stripdesc(desc) if date: parseddate = "%d %d" % util.parsedate(date) else: parseddate = "%d %d" % util.makedate() if extra: branch = extra.get("branch") if branch in ("default", ""): del extra["branch"] elif branch in (".", "null", "tip"): raise error.RevlogError(_('the name \'%s\' is reserved') % branch) if extra: extra = encodeextra(extra) parseddate = "%s %s" % (parseddate, extra) l = [hex(manifest), user, parseddate] + sorted(files) + ["", desc] text = "\n".join(l) return self.addrevision(text, transaction, len(self), p1, p2) def branchinfo(self, rev): """return the branch name and open/close state of a revision This function exists because creating a changectx object just to access this is costly.""" extra = self.read(rev)[5] return encoding.tolocal(extra.get("branch")), 'close' in extra