match: convert O(n) to O(log n) in exactmatcher.visitchildrenset
When using narrow, during rebase this is called (at least) once per directory in
the set of files in the commit being rebased. Every time it's called, we did the
set arithmetic (now extracted and cached), which was probably pretty cheap but
not necessary to repeat each time, looped over every item in the matcher and
kept things that started with the directory we were querying.
With very large narrowspecs, and a commit that touched a file in a large number
of directories, this was slow. In a pathological repo, the rebase of a single
commit (that touched over 17k files, I believe in approximately as many
directories) with a narrowspec that had >32k entries took 8,246s of profiled
time, with 5,007s of that spent in visitchildrenset (transitively). With this
change, the time spent in visitchildrenset is less than 34s (which is where my
profile cut off). Most of the remaining time was network access due to our
custom remotefilelog-based setup not properly prefetching.
Differential Revision: https://phab.mercurial-scm.org/D10294
from __future__ import absolute_import, print_function
import binascii
import getopt
import math
import os
import random
import sys
import time
from mercurial.node import nullrev
from mercurial import (
ancestor,
debugcommands,
hg,
pycompat,
ui as uimod,
util,
)
if pycompat.ispy3:
long = int
xrange = range
def buildgraph(rng, nodes=100, rootprob=0.05, mergeprob=0.2, prevprob=0.7):
"""nodes: total number of nodes in the graph
rootprob: probability that a new node (not 0) will be a root
mergeprob: probability that, excluding a root a node will be a merge
prevprob: probability that p1 will be the previous node
return value is a graph represented as an adjacency list.
"""
graph = [None] * nodes
for i in xrange(nodes):
if i == 0 or rng.random() < rootprob:
graph[i] = [nullrev]
elif i == 1:
graph[i] = [0]
elif rng.random() < mergeprob:
if i == 2 or rng.random() < prevprob:
# p1 is prev
p1 = i - 1
else:
p1 = rng.randrange(i - 1)
p2 = rng.choice(list(range(0, p1)) + list(range(p1 + 1, i)))
graph[i] = [p1, p2]
elif rng.random() < prevprob:
graph[i] = [i - 1]
else:
graph[i] = [rng.randrange(i - 1)]
return graph
def buildancestorsets(graph):
ancs = [None] * len(graph)
for i in xrange(len(graph)):
ancs[i] = {i}
if graph[i] == [nullrev]:
continue
for p in graph[i]:
ancs[i].update(ancs[p])
return ancs
class naiveincrementalmissingancestors(object):
def __init__(self, ancs, bases):
self.ancs = ancs
self.bases = set(bases)
def addbases(self, newbases):
self.bases.update(newbases)
def removeancestorsfrom(self, revs):
for base in self.bases:
if base != nullrev:
revs.difference_update(self.ancs[base])
revs.discard(nullrev)
def missingancestors(self, revs):
res = set()
for rev in revs:
if rev != nullrev:
res.update(self.ancs[rev])
for base in self.bases:
if base != nullrev:
res.difference_update(self.ancs[base])
return sorted(res)
def test_missingancestors(seed, rng):
# empirically observed to take around 1 second
graphcount = 100
testcount = 10
inccount = 10
nerrs = [0]
# the default mu and sigma give us a nice distribution of mostly
# single-digit counts (including 0) with some higher ones
def lognormrandom(mu, sigma):
return int(math.floor(rng.lognormvariate(mu, sigma)))
def samplerevs(nodes, mu=1.1, sigma=0.8):
count = min(lognormrandom(mu, sigma), len(nodes))
return rng.sample(nodes, count)
def err(seed, graph, bases, seq, output, expected):
if nerrs[0] == 0:
print('seed:', hex(seed)[:-1], file=sys.stderr)
if gerrs[0] == 0:
print('graph:', graph, file=sys.stderr)
print('* bases:', bases, file=sys.stderr)
print('* seq: ', seq, file=sys.stderr)
print('* output: ', output, file=sys.stderr)
print('* expected:', expected, file=sys.stderr)
nerrs[0] += 1
gerrs[0] += 1
for g in xrange(graphcount):
graph = buildgraph(rng)
ancs = buildancestorsets(graph)
gerrs = [0]
for _ in xrange(testcount):
# start from nullrev to include it as a possibility
graphnodes = range(nullrev, len(graph))
bases = samplerevs(graphnodes)
# fast algorithm
inc = ancestor.incrementalmissingancestors(graph.__getitem__, bases)
# reference slow algorithm
naiveinc = naiveincrementalmissingancestors(ancs, bases)
seq = []
for _ in xrange(inccount):
if rng.random() < 0.2:
newbases = samplerevs(graphnodes)
seq.append(('addbases', newbases))
inc.addbases(newbases)
naiveinc.addbases(newbases)
if rng.random() < 0.4:
# larger set so that there are more revs to remove from
revs = samplerevs(graphnodes, mu=1.5)
seq.append(('removeancestorsfrom', revs))
hrevs = set(revs)
rrevs = set(revs)
inc.removeancestorsfrom(hrevs)
naiveinc.removeancestorsfrom(rrevs)
if hrevs != rrevs:
err(
seed,
graph,
bases,
seq,
sorted(hrevs),
sorted(rrevs),
)
else:
revs = samplerevs(graphnodes)
seq.append(('missingancestors', revs))
h = inc.missingancestors(revs)
r = naiveinc.missingancestors(revs)
if h != r:
err(seed, graph, bases, seq, h, r)
# graph is a dict of child->parent adjacency lists for this graph:
# o 13
# |
# | o 12
# | |
# | | o 11
# | | |\
# | | | | o 10
# | | | | |
# | o---+ | 9
# | | | | |
# o | | | | 8
# / / / /
# | | o | 7
# | | | |
# o---+ | 6
# / / /
# | | o 5
# | |/
# | o 4
# | |
# o | 3
# | |
# | o 2
# |/
# o 1
# |
# o 0
graph = {
0: [-1, -1],
1: [0, -1],
2: [1, -1],
3: [1, -1],
4: [2, -1],
5: [4, -1],
6: [4, -1],
7: [4, -1],
8: [-1, -1],
9: [6, 7],
10: [5, -1],
11: [3, 7],
12: [9, -1],
13: [8, -1],
}
def test_missingancestors_explicit():
"""A few explicit cases, easier to check for catching errors in refactors.
The bigger graph at the end has been produced by the random generator
above, and we have some evidence that the other tests don't cover it.
"""
for i, (bases, revs) in enumerate(
(
({1, 2, 3, 4, 7}, set(xrange(10))),
({10}, set({11, 12, 13, 14})),
({7}, set({1, 2, 3, 4, 5})),
)
):
print("%% removeancestorsfrom(), example %d" % (i + 1))
missanc = ancestor.incrementalmissingancestors(graph.get, bases)
missanc.removeancestorsfrom(revs)
print("remaining (sorted): %s" % sorted(list(revs)))
for i, (bases, revs) in enumerate(
(
({10}, {11}),
({11}, {10}),
({7}, {9, 11}),
)
):
print("%% missingancestors(), example %d" % (i + 1))
missanc = ancestor.incrementalmissingancestors(graph.get, bases)
print("return %s" % missanc.missingancestors(revs))
print("% removeancestorsfrom(), bigger graph")
vecgraph = [
[-1, -1],
[0, -1],
[1, 0],
[2, 1],
[3, -1],
[4, -1],
[5, 1],
[2, -1],
[7, -1],
[8, -1],
[9, -1],
[10, 1],
[3, -1],
[12, -1],
[13, -1],
[14, -1],
[4, -1],
[16, -1],
[17, -1],
[18, -1],
[19, 11],
[20, -1],
[21, -1],
[22, -1],
[23, -1],
[2, -1],
[3, -1],
[26, 24],
[27, -1],
[28, -1],
[12, -1],
[1, -1],
[1, 9],
[32, -1],
[33, -1],
[34, 31],
[35, -1],
[36, 26],
[37, -1],
[38, -1],
[39, -1],
[40, -1],
[41, -1],
[42, 26],
[0, -1],
[44, -1],
[45, 4],
[40, -1],
[47, -1],
[36, 0],
[49, -1],
[-1, -1],
[51, -1],
[52, -1],
[53, -1],
[14, -1],
[55, -1],
[15, -1],
[23, -1],
[58, -1],
[59, -1],
[2, -1],
[61, 59],
[62, -1],
[63, -1],
[-1, -1],
[65, -1],
[66, -1],
[67, -1],
[68, -1],
[37, 28],
[69, 25],
[71, -1],
[72, -1],
[50, 2],
[74, -1],
[12, -1],
[18, -1],
[77, -1],
[78, -1],
[79, -1],
[43, 33],
[81, -1],
[82, -1],
[83, -1],
[84, 45],
[85, -1],
[86, -1],
[-1, -1],
[88, -1],
[-1, -1],
[76, 83],
[44, -1],
[92, -1],
[93, -1],
[9, -1],
[95, 67],
[96, -1],
[97, -1],
[-1, -1],
]
problem_rev = 28
problem_base = 70
# problem_rev is a parent of problem_base, but a faulty implementation
# could forget to remove it.
bases = {60, 26, 70, 3, 96, 19, 98, 49, 97, 47, 1, 6}
if problem_rev not in vecgraph[problem_base] or problem_base not in bases:
print("Conditions have changed")
missanc = ancestor.incrementalmissingancestors(vecgraph.__getitem__, bases)
revs = {4, 12, 41, 28, 68, 38, 1, 30, 56, 44}
missanc.removeancestorsfrom(revs)
if 28 in revs:
print("Failed!")
else:
print("Ok")
def genlazyancestors(revs, stoprev=0, inclusive=False):
print(
(
"%% lazy ancestor set for %s, stoprev = %s, inclusive = %s"
% (revs, stoprev, inclusive)
)
)
return ancestor.lazyancestors(
graph.get, revs, stoprev=stoprev, inclusive=inclusive
)
def printlazyancestors(s, l):
print('membership: %r' % [n for n in l if n in s])
print('iteration: %r' % list(s))
def test_lazyancestors():
# Empty revs
s = genlazyancestors([])
printlazyancestors(s, [3, 0, -1])
# Standard example
s = genlazyancestors([11, 13])
printlazyancestors(s, [11, 13, 7, 9, 8, 3, 6, 4, 1, -1, 0])
# Standard with ancestry in the initial set (1 is ancestor of 3)
s = genlazyancestors([1, 3])
printlazyancestors(s, [1, -1, 0])
# Including revs
s = genlazyancestors([11, 13], inclusive=True)
printlazyancestors(s, [11, 13, 7, 9, 8, 3, 6, 4, 1, -1, 0])
# Test with stoprev
s = genlazyancestors([11, 13], stoprev=6)
printlazyancestors(s, [11, 13, 7, 9, 8, 3, 6, 4, 1, -1, 0])
s = genlazyancestors([11, 13], stoprev=6, inclusive=True)
printlazyancestors(s, [11, 13, 7, 9, 8, 3, 6, 4, 1, -1, 0])
# Test with stoprev >= min(initrevs)
s = genlazyancestors([11, 13], stoprev=11, inclusive=True)
printlazyancestors(s, [11, 13, 7, 9, 8, 3, 6, 4, 1, -1, 0])
s = genlazyancestors([11, 13], stoprev=12, inclusive=True)
printlazyancestors(s, [11, 13, 7, 9, 8, 3, 6, 4, 1, -1, 0])
# Contiguous chains: 5->4, 2->1 (where 1 is in seen set), 1->0
s = genlazyancestors([10, 1], inclusive=True)
printlazyancestors(s, [2, 10, 4, 5, -1, 0, 1])
# The C gca algorithm requires a real repo. These are textual descriptions of
# DAGs that have been known to be problematic, and, optionally, known pairs
# of revisions and their expected ancestor list.
dagtests = [
(b'+2*2*2/*3/2', {}),
(b'+3*3/*2*2/*4*4/*4/2*4/2*2', {}),
(b'+2*2*/2*4*/4*/3*2/4', {(6, 7): [3, 5]}),
]
def test_gca():
u = uimod.ui.load()
for i, (dag, tests) in enumerate(dagtests):
repo = hg.repository(u, b'gca%d' % i, create=1)
cl = repo.changelog
if not util.safehasattr(cl.index, 'ancestors'):
# C version not available
return
debugcommands.debugbuilddag(u, repo, dag)
# Compare the results of the Python and C versions. This does not
# include choosing a winner when more than one gca exists -- we make
# sure both return exactly the same set of gcas.
# Also compare against expected results, if available.
for a in cl:
for b in cl:
cgcas = sorted(cl.index.ancestors(a, b))
pygcas = sorted(ancestor.ancestors(cl.parentrevs, a, b))
expected = None
if (a, b) in tests:
expected = tests[(a, b)]
if cgcas != pygcas or (expected and cgcas != expected):
print(
"test_gca: for dag %s, gcas for %d, %d:" % (dag, a, b)
)
print(" C returned: %s" % cgcas)
print(" Python returned: %s" % pygcas)
if expected:
print(" expected: %s" % expected)
def main():
seed = None
opts, args = getopt.getopt(sys.argv[1:], 's:', ['seed='])
for o, a in opts:
if o in ('-s', '--seed'):
seed = long(a, base=0) # accepts base 10 or 16 strings
if seed is None:
try:
seed = long(binascii.hexlify(os.urandom(16)), 16)
except AttributeError:
seed = long(time.time() * 1000)
rng = random.Random(seed)
test_missingancestors_explicit()
test_missingancestors(seed, rng)
test_lazyancestors()
test_gca()
if __name__ == '__main__':
main()