##// END OF EJS Templates
compression: introduce a `storage.revlog.zlib.level` configuration...
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

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remotefilelog.py
452 lines | 15.3 KiB | text/x-python | PythonLexer
# remotefilelog.py - filelog implementation where filelog history is stored
# remotely
#
# Copyright 2013 Facebook, Inc.
#
# 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
import os
from mercurial.node import bin, nullid
from mercurial.i18n import _
from mercurial import (
ancestor,
error,
mdiff,
revlog,
)
from mercurial.utils import storageutil
from . import (
constants,
fileserverclient,
shallowutil,
)
class remotefilelognodemap(object):
def __init__(self, filename, store):
self._filename = filename
self._store = store
def __contains__(self, node):
missing = self._store.getmissing([(self._filename, node)])
return not bool(missing)
def __get__(self, node):
if node not in self:
raise KeyError(node)
return node
class remotefilelog(object):
_generaldelta = True
def __init__(self, opener, path, repo):
self.opener = opener
self.filename = path
self.repo = repo
self.nodemap = remotefilelognodemap(self.filename, repo.contentstore)
self.version = 1
def read(self, node):
"""returns the file contents at this node"""
t = self.revision(node)
if not t.startswith('\1\n'):
return t
s = t.index('\1\n', 2)
return t[s + 2:]
def add(self, text, meta, transaction, linknode, p1=None, p2=None):
# hash with the metadata, like in vanilla filelogs
hashtext = shallowutil.createrevlogtext(text, meta.get('copy'),
meta.get('copyrev'))
node = storageutil.hashrevisionsha1(hashtext, p1, p2)
return self.addrevision(hashtext, transaction, linknode, p1, p2,
node=node)
def _createfileblob(self, text, meta, flags, p1, p2, node, linknode):
# text passed to "_createfileblob" does not include filelog metadata
header = shallowutil.buildfileblobheader(len(text), flags)
data = "%s\0%s" % (header, text)
realp1 = p1
copyfrom = ""
if meta and 'copy' in meta:
copyfrom = meta['copy']
realp1 = bin(meta['copyrev'])
data += "%s%s%s%s%s\0" % (node, realp1, p2, linknode, copyfrom)
visited = set()
pancestors = {}
queue = []
if realp1 != nullid:
p1flog = self
if copyfrom:
p1flog = remotefilelog(self.opener, copyfrom, self.repo)
pancestors.update(p1flog.ancestormap(realp1))
queue.append(realp1)
visited.add(realp1)
if p2 != nullid:
pancestors.update(self.ancestormap(p2))
queue.append(p2)
visited.add(p2)
ancestortext = ""
# add the ancestors in topological order
while queue:
c = queue.pop(0)
pa1, pa2, ancestorlinknode, pacopyfrom = pancestors[c]
pacopyfrom = pacopyfrom or ''
ancestortext += "%s%s%s%s%s\0" % (
c, pa1, pa2, ancestorlinknode, pacopyfrom)
if pa1 != nullid and pa1 not in visited:
queue.append(pa1)
visited.add(pa1)
if pa2 != nullid and pa2 not in visited:
queue.append(pa2)
visited.add(pa2)
data += ancestortext
return data
def addrevision(self, text, transaction, linknode, p1, p2, cachedelta=None,
node=None, flags=revlog.REVIDX_DEFAULT_FLAGS):
# text passed to "addrevision" includes hg filelog metadata header
if node is None:
node = storageutil.hashrevisionsha1(text, p1, p2)
meta, metaoffset = storageutil.parsemeta(text)
rawtext, validatehash = self._processflags(text, flags, 'write')
return self.addrawrevision(rawtext, transaction, linknode, p1, p2,
node, flags, cachedelta,
_metatuple=(meta, metaoffset))
def addrawrevision(self, rawtext, transaction, linknode, p1, p2, node,
flags, cachedelta=None, _metatuple=None):
if _metatuple:
# _metatuple: used by "addrevision" internally by remotefilelog
# meta was parsed confidently
meta, metaoffset = _metatuple
else:
# not from self.addrevision, but something else (repo._filecommit)
# calls addrawrevision directly. remotefilelog needs to get and
# strip filelog metadata.
# we don't have confidence about whether rawtext contains filelog
# metadata or not (flag processor could replace it), so we just
# parse it as best-effort.
# in LFS (flags != 0)'s case, the best way is to call LFS code to
# get the meta information, instead of storageutil.parsemeta.
meta, metaoffset = storageutil.parsemeta(rawtext)
if flags != 0:
# when flags != 0, be conservative and do not mangle rawtext, since
# a read flag processor expects the text not being mangled at all.
metaoffset = 0
if metaoffset:
# remotefilelog fileblob stores copy metadata in its ancestortext,
# not its main blob. so we need to remove filelog metadata
# (containing copy information) from text.
blobtext = rawtext[metaoffset:]
else:
blobtext = rawtext
data = self._createfileblob(blobtext, meta, flags, p1, p2, node,
linknode)
self.repo.contentstore.addremotefilelognode(self.filename, node, data)
return node
def renamed(self, node):
ancestors = self.repo.metadatastore.getancestors(self.filename, node)
p1, p2, linknode, copyfrom = ancestors[node]
if copyfrom:
return (copyfrom, p1)
return False
def size(self, node):
"""return the size of a given revision"""
return len(self.read(node))
rawsize = size
def cmp(self, node, text):
"""compare text with a given file revision
returns True if text is different than what is stored.
"""
if node == nullid:
return True
nodetext = self.read(node)
return nodetext != text
def __nonzero__(self):
return True
__bool__ = __nonzero__
def __len__(self):
if self.filename == '.hgtags':
# The length of .hgtags is used to fast path tag checking.
# remotefilelog doesn't support .hgtags since the entire .hgtags
# history is needed. Use the excludepattern setting to make
# .hgtags a normal filelog.
return 0
raise RuntimeError("len not supported")
def empty(self):
return False
def flags(self, node):
if isinstance(node, int):
raise error.ProgrammingError(
'remotefilelog does not accept integer rev for flags')
store = self.repo.contentstore
return store.getmeta(self.filename, node).get(constants.METAKEYFLAG, 0)
def parents(self, node):
if node == nullid:
return nullid, nullid
ancestormap = self.repo.metadatastore.getancestors(self.filename, node)
p1, p2, linknode, copyfrom = ancestormap[node]
if copyfrom:
p1 = nullid
return p1, p2
def parentrevs(self, rev):
# TODO(augie): this is a node and should be a rev, but for now
# nothing in core seems to actually break.
return self.parents(rev)
def linknode(self, node):
ancestormap = self.repo.metadatastore.getancestors(self.filename, node)
p1, p2, linknode, copyfrom = ancestormap[node]
return linknode
def linkrev(self, node):
return self.repo.unfiltered().changelog.rev(self.linknode(node))
def emitrevisions(self, nodes, nodesorder=None, revisiondata=False,
assumehaveparentrevisions=False, deltaprevious=False,
deltamode=None):
# we don't use any of these parameters here
del nodesorder, revisiondata, assumehaveparentrevisions, deltaprevious
del deltamode
prevnode = None
for node in nodes:
p1, p2 = self.parents(node)
if prevnode is None:
basenode = prevnode = p1
if basenode == node:
basenode = nullid
if basenode != nullid:
revision = None
delta = self.revdiff(basenode, node)
else:
revision = self.revision(node, raw=True)
delta = None
yield revlog.revlogrevisiondelta(
node=node,
p1node=p1,
p2node=p2,
linknode=self.linknode(node),
basenode=basenode,
flags=self.flags(node),
baserevisionsize=None,
revision=revision,
delta=delta,
)
def revdiff(self, node1, node2):
return mdiff.textdiff(self.revision(node1, raw=True),
self.revision(node2, raw=True))
def lookup(self, node):
if len(node) == 40:
node = bin(node)
if len(node) != 20:
raise error.LookupError(node, self.filename,
_('invalid lookup input'))
return node
def rev(self, node):
# This is a hack to make TortoiseHG work.
return node
def node(self, rev):
# This is a hack.
if isinstance(rev, int):
raise error.ProgrammingError(
'remotefilelog does not convert integer rev to node')
return rev
def revision(self, node, raw=False):
"""returns the revlog contents at this node.
this includes the meta data traditionally included in file revlogs.
this is generally only used for bundling and communicating with vanilla
hg clients.
"""
if node == nullid:
return ""
if len(node) != 20:
raise error.LookupError(node, self.filename,
_('invalid revision input'))
store = self.repo.contentstore
rawtext = store.get(self.filename, node)
if raw:
return rawtext
flags = store.getmeta(self.filename, node).get(constants.METAKEYFLAG, 0)
if flags == 0:
return rawtext
text, verifyhash = self._processflags(rawtext, flags, 'read')
return text
def _processflags(self, text, flags, operation, raw=False):
# mostly copied from hg/mercurial/revlog.py
validatehash = True
orderedflags = revlog.REVIDX_FLAGS_ORDER
if operation == 'write':
orderedflags = reversed(orderedflags)
for flag in orderedflags:
if flag & flags:
vhash = True
if flag not in revlog._flagprocessors:
message = _("missing processor for flag '%#x'") % (flag)
raise revlog.RevlogError(message)
readfunc, writefunc, rawfunc = revlog._flagprocessors[flag]
if raw:
vhash = rawfunc(self, text)
elif operation == 'read':
text, vhash = readfunc(self, text)
elif operation == 'write':
text, vhash = writefunc(self, text)
validatehash = validatehash and vhash
return text, validatehash
def _read(self, id):
"""reads the raw file blob from disk, cache, or server"""
fileservice = self.repo.fileservice
localcache = fileservice.localcache
cachekey = fileserverclient.getcachekey(self.repo.name, self.filename,
id)
try:
return localcache.read(cachekey)
except KeyError:
pass
localkey = fileserverclient.getlocalkey(self.filename, id)
localpath = os.path.join(self.localpath, localkey)
try:
return shallowutil.readfile(localpath)
except IOError:
pass
fileservice.prefetch([(self.filename, id)])
try:
return localcache.read(cachekey)
except KeyError:
pass
raise error.LookupError(id, self.filename, _('no node'))
def ancestormap(self, node):
return self.repo.metadatastore.getancestors(self.filename, node)
def ancestor(self, a, b):
if a == nullid or b == nullid:
return nullid
revmap, parentfunc = self._buildrevgraph(a, b)
nodemap = dict(((v, k) for (k, v) in revmap.iteritems()))
ancs = ancestor.ancestors(parentfunc, revmap[a], revmap[b])
if ancs:
# choose a consistent winner when there's a tie
return min(map(nodemap.__getitem__, ancs))
return nullid
def commonancestorsheads(self, a, b):
"""calculate all the heads of the common ancestors of nodes a and b"""
if a == nullid or b == nullid:
return nullid
revmap, parentfunc = self._buildrevgraph(a, b)
nodemap = dict(((v, k) for (k, v) in revmap.iteritems()))
ancs = ancestor.commonancestorsheads(parentfunc, revmap[a], revmap[b])
return map(nodemap.__getitem__, ancs)
def _buildrevgraph(self, a, b):
"""Builds a numeric revision graph for the given two nodes.
Returns a node->rev map and a rev->[revs] parent function.
"""
amap = self.ancestormap(a)
bmap = self.ancestormap(b)
# Union the two maps
parentsmap = collections.defaultdict(list)
allparents = set()
for mapping in (amap, bmap):
for node, pdata in mapping.iteritems():
parents = parentsmap[node]
p1, p2, linknode, copyfrom = pdata
# Don't follow renames (copyfrom).
# remotefilectx.ancestor does that.
if p1 != nullid and not copyfrom:
parents.append(p1)
allparents.add(p1)
if p2 != nullid:
parents.append(p2)
allparents.add(p2)
# Breadth first traversal to build linkrev graph
parentrevs = collections.defaultdict(list)
revmap = {}
queue = collections.deque(((None, n) for n in parentsmap
if n not in allparents))
while queue:
prevrev, current = queue.pop()
if current in revmap:
if prevrev:
parentrevs[prevrev].append(revmap[current])
continue
# Assign linkrevs in reverse order, so start at
# len(parentsmap) and work backwards.
currentrev = len(parentsmap) - len(revmap) - 1
revmap[current] = currentrev
if prevrev:
parentrevs[prevrev].append(currentrev)
for parent in parentsmap.get(current):
queue.appendleft((currentrev, parent))
return revmap, parentrevs.__getitem__
def strip(self, minlink, transaction):
pass
# misc unused things
def files(self):
return []
def checksize(self):
return 0, 0