Mercurial > hg
view mercurial/hbisect.py @ 42743:8c9a6adec67a
rust-discovery: using the children cache in add_missing
The DAG range computation often needs to get back to very old
revisions, and turns out to be disproportionately long, given
that the end goal is to remove the descendents of the given
missing revisons from the undecided set.
The fast iteration capabilities available in the Rust case make
it possible to avoid the DAG range entirely, at the cost of
precomputing the children cache, and to simply iterate on
children of the given missing revisions.
This is a case where staying on the same side of the interface
between the two languages has clear benefits.
On discoveries with initial undecided sets
small enough to bypass sampling entirely, the total cost of
computing the children cache and the subsequent iteration
becomes better than the Python + C counterpart, which relies on
reachableroots2.
For example, on a repo with more than one million revisions with
an initial undecided set of 11 elements, we get these figures:
Rust version with simple iteration
addcommons: 57.287us
first undecided computation: 184.278334ms
first children cache computation: 131.056us
addmissings iteration: 42.766us
first addinfo total: 185.24 ms
Python + C version
first addcommons: 0.29 ms
addcommons 0.21 ms
first undecided computation 191.35 ms
addmissings 45.75 ms
first addinfo total: 237.77 ms
On discoveries with large undecided sets, the initial price paid
makes the first addinfo slower than the Python + C version,
but that's more than compensated by the gain in sampling and
subsequent iterations.
Here's an extreme example with an undecided set of a million revisions:
Rust version:
first undecided computation: 293.842629ms
first children cache computation: 407.911297ms
addmissings iteration: 34.312869ms
first addinfo total: 776.02 ms
taking initial sample
query 2: sampling time: 1318.38 ms
query 2; still undecided: 1005013, sample size is: 200
addmissings: 143.062us
Python + C version:
first undecided computation 298.13 ms
addmissings 80.13 ms
first addinfo total: 399.62 ms
taking initial sample
query 2: sampling time: 3957.23 ms
query 2; still undecided: 1005013, sample size is: 200
addmissings 52.88 ms
Differential Revision: https://phab.mercurial-scm.org/D6428
author | Georges Racinet <georges.racinet@octobus.net> |
---|---|
date | Tue, 16 Apr 2019 01:16:39 +0200 |
parents | 21eda240be07 |
children | 2372284d9457 |
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# changelog bisection for mercurial # # Copyright 2007 Matt Mackall # Copyright 2005, 2006 Benoit Boissinot <benoit.boissinot@ens-lyon.org> # # Inspired by git bisect, extension skeleton taken from mq.py. # # 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 ( hex, short, ) from . import ( error, ) def bisect(repo, state): """find the next node (if any) for testing during a bisect search. returns a (nodes, number, good) tuple. 'nodes' is the final result of the bisect if 'number' is 0. Otherwise 'number' indicates the remaining possible candidates for the search and 'nodes' contains the next bisect target. 'good' is True if bisect is searching for a first good changeset, False if searching for a first bad one. """ repo = repo.unfiltered() changelog = repo.changelog clparents = changelog.parentrevs skip = {changelog.rev(n) for n in state['skip']} def buildancestors(bad, good): badrev = min([changelog.rev(n) for n in bad]) ancestors = collections.defaultdict(lambda: None) for rev in repo.revs("descendants(%ln) - ancestors(%ln)", good, good): ancestors[rev] = [] if ancestors[badrev] is None: return badrev, None return badrev, ancestors good = False badrev, ancestors = buildancestors(state['bad'], state['good']) if not ancestors: # looking for bad to good transition? good = True badrev, ancestors = buildancestors(state['good'], state['bad']) bad = changelog.node(badrev) if not ancestors: # now we're confused if (len(state['bad']) == 1 and len(state['good']) == 1 and state['bad'] != state['good']): raise error.Abort(_("starting revisions are not directly related")) raise error.Abort(_("inconsistent state, %d:%s is good and bad") % (badrev, short(bad))) # build children dict children = {} visit = collections.deque([badrev]) candidates = [] while visit: rev = visit.popleft() if ancestors[rev] == []: candidates.append(rev) for prev in clparents(rev): if prev != -1: if prev in children: children[prev].append(rev) else: children[prev] = [rev] visit.append(prev) candidates.sort() # have we narrowed it down to one entry? # or have all other possible candidates besides 'bad' have been skipped? tot = len(candidates) unskipped = [c for c in candidates if (c not in skip) and (c != badrev)] if tot == 1 or not unskipped: return ([changelog.node(c) for c in candidates], 0, good) perfect = tot // 2 # find the best node to test best_rev = None best_len = -1 poison = set() for rev in candidates: if rev in poison: # poison children poison.update(children.get(rev, [])) continue a = ancestors[rev] or [rev] ancestors[rev] = None x = len(a) # number of ancestors y = tot - x # number of non-ancestors value = min(x, y) # how good is this test? if value > best_len and rev not in skip: best_len = value best_rev = rev if value == perfect: # found a perfect candidate? quit early break if y < perfect and rev not in skip: # all downhill from here? # poison children poison.update(children.get(rev, [])) continue for c in children.get(rev, []): if ancestors[c]: ancestors[c] = list(set(ancestors[c] + a)) else: ancestors[c] = a + [c] assert best_rev is not None best_node = changelog.node(best_rev) return ([best_node], tot, good) def extendrange(repo, state, nodes, good): # bisect is incomplete when it ends on a merge node and # one of the parent was not checked. parents = repo[nodes[0]].parents() if len(parents) > 1: if good: side = state['bad'] else: side = state['good'] num = len(set(i.node() for i in parents) & set(side)) if num == 1: return parents[0].ancestor(parents[1]) return None def load_state(repo): state = {'current': [], 'good': [], 'bad': [], 'skip': []} for l in repo.vfs.tryreadlines("bisect.state"): kind, node = l[:-1].split() node = repo.unfiltered().lookup(node) if kind not in state: raise error.Abort(_("unknown bisect kind %s") % kind) state[kind].append(node) return state def save_state(repo, state): f = repo.vfs("bisect.state", "w", atomictemp=True) with repo.wlock(): for kind in sorted(state): for node in state[kind]: f.write("%s %s\n" % (kind, hex(node))) f.close() def resetstate(repo): """remove any bisect state from the repository""" if repo.vfs.exists("bisect.state"): repo.vfs.unlink("bisect.state") def checkstate(state): """check we have both 'good' and 'bad' to define a range Raise Abort exception otherwise.""" if state['good'] and state['bad']: return True if not state['good']: raise error.Abort(_('cannot bisect (no known good revisions)')) else: raise error.Abort(_('cannot bisect (no known bad revisions)')) def get(repo, status): """ Return a list of revision(s) that match the given status: - ``good``, ``bad``, ``skip``: csets explicitly marked as good/bad/skip - ``goods``, ``bads`` : csets topologically good/bad - ``range`` : csets taking part in the bisection - ``pruned`` : csets that are goods, bads or skipped - ``untested`` : csets whose fate is yet unknown - ``ignored`` : csets ignored due to DAG topology - ``current`` : the cset currently being bisected """ state = load_state(repo) if status in ('good', 'bad', 'skip', 'current'): return map(repo.unfiltered().changelog.rev, state[status]) else: # In the following sets, we do *not* call 'bisect()' with more # than one level of recursion, because that can be very, very # time consuming. Instead, we always develop the expression as # much as possible. # 'range' is all csets that make the bisection: # - have a good ancestor and a bad descendant, or conversely # that's because the bisection can go either way range = '( bisect(bad)::bisect(good) | bisect(good)::bisect(bad) )' _t = repo.revs('bisect(good)::bisect(bad)') # The sets of topologically good or bad csets if len(_t) == 0: # Goods are topologically after bads goods = 'bisect(good)::' # Pruned good csets bads = '::bisect(bad)' # Pruned bad csets else: # Goods are topologically before bads goods = '::bisect(good)' # Pruned good csets bads = 'bisect(bad)::' # Pruned bad csets # 'pruned' is all csets whose fate is already known: good, bad, skip skips = 'bisect(skip)' # Pruned skipped csets pruned = '( (%s) | (%s) | (%s) )' % (goods, bads, skips) # 'untested' is all cset that are- in 'range', but not in 'pruned' untested = '( (%s) - (%s) )' % (range, pruned) # 'ignored' is all csets that were not used during the bisection # due to DAG topology, but may however have had an impact. # E.g., a branch merged between bads and goods, but whose branch- # point is out-side of the range. iba = '::bisect(bad) - ::bisect(good)' # Ignored bads' ancestors iga = '::bisect(good) - ::bisect(bad)' # Ignored goods' ancestors ignored = '( ( (%s) | (%s) ) - (%s) )' % (iba, iga, range) if status == 'range': return repo.revs(range) elif status == 'pruned': return repo.revs(pruned) elif status == 'untested': return repo.revs(untested) elif status == 'ignored': return repo.revs(ignored) elif status == "goods": return repo.revs(goods) elif status == "bads": return repo.revs(bads) else: raise error.ParseError(_('invalid bisect state')) def label(repo, node): rev = repo.changelog.rev(node) # Try explicit sets if rev in get(repo, 'good'): # i18n: bisect changeset status return _('good') if rev in get(repo, 'bad'): # i18n: bisect changeset status return _('bad') if rev in get(repo, 'skip'): # i18n: bisect changeset status return _('skipped') if rev in get(repo, 'untested') or rev in get(repo, 'current'): # i18n: bisect changeset status return _('untested') if rev in get(repo, 'ignored'): # i18n: bisect changeset status return _('ignored') # Try implicit sets if rev in get(repo, 'goods'): # i18n: bisect changeset status return _('good (implicit)') if rev in get(repo, 'bads'): # i18n: bisect changeset status return _('bad (implicit)') return None def printresult(ui, repo, state, displayer, nodes, good): repo = repo.unfiltered() if len(nodes) == 1: # narrowed it down to a single revision if good: ui.write(_("The first good revision is:\n")) else: ui.write(_("The first bad revision is:\n")) displayer.show(repo[nodes[0]]) extendnode = extendrange(repo, state, nodes, good) if extendnode is not None: ui.write(_('Not all ancestors of this changeset have been' ' checked.\nUse bisect --extend to continue the ' 'bisection from\nthe common ancestor, %s.\n') % extendnode) else: # multiple possible revisions if good: ui.write(_("Due to skipped revisions, the first " "good revision could be any of:\n")) else: ui.write(_("Due to skipped revisions, the first " "bad revision could be any of:\n")) for n in nodes: displayer.show(repo[n]) displayer.close()