Mercurial > hg-stable
view tests/flagprocessorext.py @ 32200:4d504e541d3d
rebase: use matcher to optimize manifestmerge
The old merge code would call manifestmerge and calculate the complete diff
between the source to the destination. In many cases, like rebase, the vast
majority of differences between the source and destination are irrelevant
because they are differences between the destination and the common ancestor
only, and therefore don't affect the merge. Since most actions are 'keep', all
the effort to compute them is wasted.
Instead, let's compute the difference between the source and the common ancestor
and only perform the diff of those files against the merge destination. When
using treemanifest, this lets us avoid loading almost the entire tree when
rebasing from a very old ancestor. This speeds up rebase of an old stack of 27
commits by 20x.
In mozilla-central, without treemanifest, when rebasing a commit from
default~100000 to default, this speeds up the manifestmerge step from 2.6s to
1.2s. However, the additional diff adds an overhead to all manifestmerge calls,
especially for flat manifests. When rebasing a commit from default~1 to default
it appears to add 100ms in mozilla-central. While we could put this optimization
behind a flag, I think the fact that it makes merge O(number of changes being
applied) instead of O(number of changes between X and Y) justifies it.
author | Durham Goode <durham@fb.com> |
---|---|
date | Wed, 03 May 2017 10:43:59 -0700 |
parents | 77f746e5383a |
children | 3e3f4c03876b |
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# coding=UTF-8 from __future__ import absolute_import import base64 import zlib from mercurial import ( changegroup, exchange, extensions, filelog, revlog, util, ) # Test only: These flags are defined here only in the context of testing the # behavior of the flag processor. The canonical way to add flags is to get in # touch with the community and make them known in revlog. REVIDX_NOOP = (1 << 3) REVIDX_BASE64 = (1 << 2) REVIDX_GZIP = (1 << 1) REVIDX_FAIL = 1 def validatehash(self, text): return True def bypass(self, text): return False def noopdonothing(self, text): return (text, True) def b64encode(self, text): return (base64.b64encode(text), False) def b64decode(self, text): return (base64.b64decode(text), True) def gzipcompress(self, text): return (zlib.compress(text), False) def gzipdecompress(self, text): return (zlib.decompress(text), True) def supportedoutgoingversions(orig, repo): versions = orig(repo) versions.discard('01') versions.discard('02') versions.add('03') return versions def allsupportedversions(orig, ui): versions = orig(ui) versions.add('03') return versions def noopaddrevision(orig, self, text, transaction, link, p1, p2, cachedelta=None, node=None, flags=revlog.REVIDX_DEFAULT_FLAGS): if '[NOOP]' in text: flags |= REVIDX_NOOP return orig(self, text, transaction, link, p1, p2, cachedelta=cachedelta, node=node, flags=flags) def b64addrevision(orig, self, text, transaction, link, p1, p2, cachedelta=None, node=None, flags=revlog.REVIDX_DEFAULT_FLAGS): if '[BASE64]' in text: flags |= REVIDX_BASE64 return orig(self, text, transaction, link, p1, p2, cachedelta=cachedelta, node=node, flags=flags) def gzipaddrevision(orig, self, text, transaction, link, p1, p2, cachedelta=None, node=None, flags=revlog.REVIDX_DEFAULT_FLAGS): if '[GZIP]' in text: flags |= REVIDX_GZIP return orig(self, text, transaction, link, p1, p2, cachedelta=cachedelta, node=node, flags=flags) def failaddrevision(orig, self, text, transaction, link, p1, p2, cachedelta=None, node=None, flags=revlog.REVIDX_DEFAULT_FLAGS): # This addrevision wrapper is meant to add a flag we will not have # transforms registered for, ensuring we handle this error case. if '[FAIL]' in text: flags |= REVIDX_FAIL return orig(self, text, transaction, link, p1, p2, cachedelta=cachedelta, node=node, flags=flags) def extsetup(ui): # Enable changegroup3 for flags to be sent over the wire wrapfunction = extensions.wrapfunction wrapfunction(changegroup, 'supportedoutgoingversions', supportedoutgoingversions) wrapfunction(changegroup, 'allsupportedversions', allsupportedversions) # Teach revlog about our test flags flags = [REVIDX_NOOP, REVIDX_BASE64, REVIDX_GZIP, REVIDX_FAIL] revlog.REVIDX_KNOWN_FLAGS |= util.bitsfrom(flags) revlog.REVIDX_FLAGS_ORDER.extend(flags) # Teach exchange to use changegroup 3 for k in exchange._bundlespeccgversions.keys(): exchange._bundlespeccgversions[k] = '03' # Add wrappers for addrevision, responsible to set flags depending on the # revision data contents. wrapfunction(filelog.filelog, 'addrevision', noopaddrevision) wrapfunction(filelog.filelog, 'addrevision', b64addrevision) wrapfunction(filelog.filelog, 'addrevision', gzipaddrevision) wrapfunction(filelog.filelog, 'addrevision', failaddrevision) # Register flag processors for each extension revlog.addflagprocessor( REVIDX_NOOP, ( noopdonothing, noopdonothing, validatehash, ) ) revlog.addflagprocessor( REVIDX_BASE64, ( b64decode, b64encode, bypass, ), ) revlog.addflagprocessor( REVIDX_GZIP, ( gzipdecompress, gzipcompress, bypass ) )