Mercurial > hg
view mercurial/scmwindows.py @ 32151:4d504e541d3d
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 | bf5e13e38390 |
children | d74b0cff94a9 |
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from __future__ import absolute_import import os from . import ( encoding, osutil, pycompat, util, win32, ) try: import _winreg as winreg winreg.CloseKey except ImportError: import winreg # MS-DOS 'more' is the only pager available by default on Windows. fallbackpager = 'more' def systemrcpath(): '''return default os-specific hgrc search path''' rcpath = [] filename = util.executablepath() # Use mercurial.ini found in directory with hg.exe progrc = os.path.join(os.path.dirname(filename), 'mercurial.ini') rcpath.append(progrc) # Use hgrc.d found in directory with hg.exe progrcd = os.path.join(os.path.dirname(filename), 'hgrc.d') if os.path.isdir(progrcd): for f, kind in osutil.listdir(progrcd): if f.endswith('.rc'): rcpath.append(os.path.join(progrcd, f)) # else look for a system rcpath in the registry value = util.lookupreg('SOFTWARE\\Mercurial', None, winreg.HKEY_LOCAL_MACHINE) if not isinstance(value, str) or not value: return rcpath value = util.localpath(value) for p in value.split(pycompat.ospathsep): if p.lower().endswith('mercurial.ini'): rcpath.append(p) elif os.path.isdir(p): for f, kind in osutil.listdir(p): if f.endswith('.rc'): rcpath.append(os.path.join(p, f)) return rcpath def userrcpath(): '''return os-specific hgrc search path to the user dir''' home = os.path.expanduser('~') path = [os.path.join(home, 'mercurial.ini'), os.path.join(home, '.hgrc')] userprofile = encoding.environ.get('USERPROFILE') if userprofile and userprofile != home: path.append(os.path.join(userprofile, 'mercurial.ini')) path.append(os.path.join(userprofile, '.hgrc')) return path def termsize(ui): return win32.termsize()