phases: rework the logic of _pushdiscoveryphase to bound complexity
This rework the various graph traversal in _pushdiscoveryphase to keep the
complexity in check.
This is done though a couple of things:
- first, limiting the space we have to explore, for example, if we are not in
publishing push, we don't need to consider remote draft roots that are also
draft locally, as there is nothing to be moved there.
- avoid unbounded descendant computation, and use the faster "rev between"
computation.
This provide a massive boost to performance when exchanging with repository with
a massive amount of draft, like mozilla-try:
### data-env-vars.name = mozilla-try-2023-03-22-zstd-sparse-revlog
# benchmark.name = hg.command.push
# bin-env-vars.hg.flavor = default
# bin-env-vars.hg.py-re2-module = default
# benchmark.variants.explicit-rev = all-out-heads
# benchmark.variants.issue6528 = disabled
# benchmark.variants.protocol = ssh
# benchmark.variants.reuse-external-delta-parent = default
## benchmark.variants.revs = any-1-extra-rev
before: 20.346590 seconds
after: 11.232059 seconds (-38.15%, -7.48 seconds)
## benchmark.variants.revs = any-100-extra-rev
before: 24.752051 seconds
after: 15.367412 seconds (-37.91%, -9.38 seconds)
After this changes, the push operation is still quite too slow. Some of this
can be attributed to general phases slowness (reading all the roots from disk
for example) and other know slowness (not using persistent-nodemap, branchmap,
tags, etc. We are also working on them, but with this series, phase discovery
during push no longer showing up in profile and this is a pretty nice and bit
low-hanging fruit out of the way.
### (same case as the above)
# benchmark.variants.revs = any-1-extra-rev
pre-%ln-change: 44.235070
this-changeset: 11.232059 seconds (-74.61%, -33.00 seconds)
# benchmark.variants.revs = any-100-extra-rev
pre-%ln-change: 49.234697
this-changeset: 15.367412 seconds (-68.79%, -33.87 seconds)
Note that with this change, the `hg push` performance is now much closer to the
`hg pull` performance, even it still lagging behind a bit. (and the overall
performance are still too slow).
### data-env-vars.name = mozilla-try-2023-03-22-ds2-pnm
# benchmark.variants.explicit-rev = all-out-heads
# benchmark.variants.issue6528 = disabled
# benchmark.variants.protocol = ssh
# benchmark.variants.pulled-delta-reuse-policy = default
# bin-env-vars.hg.flavor = rust
## benchmark.variants.revs = any-1-extra-rev
hg.command.pull: 6.517450
hg.command.push: 11.219888
## benchmark.variants.revs = any-100-extra-rev
hg.command.pull: 10.160991
hg.command.push: 14.251107
### data-env-vars.name = mozilla-try-2023-03-22-zstd-sparse-revlog
# bin-env-vars.hg.py-re2-module = default
# benchmark.variants.explicit-rev = all-out-heads
# benchmark.variants.issue6528 = disabled
# benchmark.variants.protocol = ssh
# benchmark.variants.pulled-delta-reuse-policy = default
## bin-env-vars.hg.flavor = default
## benchmark.variants.revs = any-1-extra-rev
hg.command.pull: 8.577772
hg.command.push: 11.232059
## bin-env-vars.hg.flavor = default
## benchmark.variants.revs = any-100-extra-rev
hg.command.pull: 13.152976
hg.command.push: 15.367412
## bin-env-vars.hg.flavor = rust
## benchmark.variants.revs = any-1-extra-rev
hg.command.pull: 8.731982
hg.command.push: 11.178751
## bin-env-vars.hg.flavor = rust
## benchmark.variants.revs = any-100-extra-rev
hg.command.pull: 13.184236
hg.command.push: 15.620843
import unittest
import silenttestrunner
from mercurial import util
class testlrucachedict(unittest.TestCase):
def testsimple(self):
d = util.lrucachedict(4)
self.assertEqual(d.capacity, 4)
d.insert('a', 'va', cost=2)
d['b'] = 'vb'
d['c'] = 'vc'
d.insert('d', 'vd', cost=42)
self.assertEqual(d['a'], 'va')
self.assertEqual(d['b'], 'vb')
self.assertEqual(d['c'], 'vc')
self.assertEqual(d['d'], 'vd')
self.assertEqual(d.totalcost, 44)
# 'a' should be dropped because it was least recently used.
d['e'] = 've'
self.assertNotIn('a', d)
self.assertIsNone(d.get('a'))
self.assertEqual(d.totalcost, 42)
self.assertEqual(d['b'], 'vb')
self.assertEqual(d['c'], 'vc')
self.assertEqual(d['d'], 'vd')
self.assertEqual(d['e'], 've')
# Replacing item with different cost adjusts totalcost.
d.insert('e', 've', cost=4)
self.assertEqual(d.totalcost, 46)
# Touch entries in some order (both get and set).
d['e']
d['c'] = 'vc2'
d['d']
d['b'] = 'vb2'
# 'e' should be dropped now
d['f'] = 'vf'
self.assertNotIn('e', d)
self.assertEqual(d['b'], 'vb2')
self.assertEqual(d['c'], 'vc2')
self.assertEqual(d['d'], 'vd')
self.assertEqual(d['f'], 'vf')
d.clear()
for key in ('a', 'b', 'c', 'd', 'e', 'f'):
self.assertNotIn(key, d)
def testunfull(self):
d = util.lrucachedict(4)
d['a'] = 1
d['b'] = 2
d['a']
d['b']
for key in ('a', 'b'):
self.assertIn(key, d)
def testget(self):
d = util.lrucachedict(4)
d['a'] = 'va'
d['b'] = 'vb'
d['c'] = 'vc'
self.assertIsNone(d.get('missing'))
self.assertEqual(list(d), ['c', 'b', 'a'])
self.assertEqual(d.get('a'), 'va')
self.assertEqual(list(d), ['a', 'c', 'b'])
def testpeek(self):
d = util.lrucachedict(4)
d['a'] = 'va'
d['b'] = 'vb'
d['c'] = 'vc'
with self.assertRaises(KeyError):
d.peek('missing')
self.assertEqual(list(d), ['c', 'b', 'a'])
self.assertIsNone(d.peek('missing', None))
self.assertEqual(list(d), ['c', 'b', 'a'])
self.assertEqual(d.peek('a'), 'va')
self.assertEqual(list(d), ['c', 'b', 'a'])
def testpop(self):
d = util.lrucachedict(4)
d['a'] = 'va'
d['b'] = 'vb'
d['c'] = 'vc'
with self.assertRaises(KeyError):
d.pop('missing')
self.assertEqual(list(d), ['c', 'b', 'a'])
self.assertIsNone(d.pop('missing', None))
self.assertEqual(list(d), ['c', 'b', 'a'])
self.assertEqual(d.pop('b'), 'vb')
self.assertEqual(list(d), ['c', 'a'])
def testcopypartial(self):
d = util.lrucachedict(4)
d.insert('a', 'va', cost=4)
d.insert('b', 'vb', cost=2)
dc = d.copy()
self.assertEqual(len(dc), 2)
self.assertEqual(dc.totalcost, 6)
for key in ('a', 'b'):
self.assertIn(key, dc)
self.assertEqual(dc[key], 'v%s' % key)
self.assertEqual(len(d), 2)
for key in ('a', 'b'):
self.assertIn(key, d)
self.assertEqual(d[key], 'v%s' % key)
d['c'] = 'vc'
del d['b']
self.assertEqual(d.totalcost, 4)
dc = d.copy()
self.assertEqual(len(dc), 2)
self.assertEqual(dc.totalcost, 4)
for key in ('a', 'c'):
self.assertIn(key, dc)
self.assertEqual(dc[key], 'v%s' % key)
def testcopyempty(self):
d = util.lrucachedict(4)
dc = d.copy()
self.assertEqual(len(dc), 0)
def testcopyfull(self):
d = util.lrucachedict(4)
d.insert('a', 'va', cost=42)
d['b'] = 'vb'
d['c'] = 'vc'
d['d'] = 'vd'
dc = d.copy()
for key in ('a', 'b', 'c', 'd'):
self.assertIn(key, dc)
self.assertEqual(dc[key], 'v%s' % key)
self.assertEqual(d.totalcost, 42)
self.assertEqual(dc.totalcost, 42)
# 'a' should be dropped because it was least recently used.
dc['e'] = 've'
self.assertNotIn('a', dc)
for key in ('b', 'c', 'd', 'e'):
self.assertIn(key, dc)
self.assertEqual(dc[key], 'v%s' % key)
self.assertEqual(d.totalcost, 42)
self.assertEqual(dc.totalcost, 0)
# Contents and order of original dict should remain unchanged.
dc['b'] = 'vb_new'
self.assertEqual(list(iter(d)), ['d', 'c', 'b', 'a'])
for key in ('a', 'b', 'c', 'd'):
self.assertEqual(d[key], 'v%s' % key)
d = util.lrucachedict(4, maxcost=42)
d.insert('a', 'va', cost=5)
d.insert('b', 'vb', cost=4)
d.insert('c', 'vc', cost=3)
dc = d.copy()
self.assertEqual(dc.maxcost, 42)
self.assertEqual(len(dc), 3)
# Max cost can be lowered as part of copy.
dc = d.copy(maxcost=10)
self.assertEqual(dc.maxcost, 10)
self.assertEqual(len(dc), 2)
self.assertEqual(dc.totalcost, 7)
self.assertIn('b', dc)
self.assertIn('c', dc)
def testcopydecreasecapacity(self):
d = util.lrucachedict(5)
d.insert('a', 'va', cost=4)
d.insert('b', 'vb', cost=2)
d['c'] = 'vc'
d['d'] = 'vd'
dc = d.copy(2)
self.assertEqual(dc.totalcost, 0)
for key in ('a', 'b'):
self.assertNotIn(key, dc)
for key in ('c', 'd'):
self.assertIn(key, dc)
self.assertEqual(dc[key], 'v%s' % key)
dc.insert('e', 've', cost=7)
self.assertEqual(dc.totalcost, 7)
self.assertNotIn('c', dc)
for key in ('d', 'e'):
self.assertIn(key, dc)
self.assertEqual(dc[key], 'v%s' % key)
# Original should remain unchanged.
self.assertEqual(d.totalcost, 6)
for key in ('a', 'b', 'c', 'd'):
self.assertIn(key, d)
self.assertEqual(d[key], 'v%s' % key)
def testcopyincreasecapacity(self):
d = util.lrucachedict(5)
d['a'] = 'va'
d['b'] = 'vb'
d['c'] = 'vc'
d['d'] = 'vd'
dc = d.copy(6)
for key in ('a', 'b', 'c', 'd'):
self.assertIn(key, dc)
self.assertEqual(dc[key], 'v%s' % key)
dc['e'] = 've'
dc['f'] = 'vf'
for key in ('a', 'b', 'c', 'd', 'e', 'f'):
self.assertIn(key, dc)
self.assertEqual(dc[key], 'v%s' % key)
dc['g'] = 'vg'
self.assertNotIn('a', dc)
for key in ('b', 'c', 'd', 'e', 'f', 'g'):
self.assertIn(key, dc)
self.assertEqual(dc[key], 'v%s' % key)
# Original should remain unchanged.
for key in ('a', 'b', 'c', 'd'):
self.assertIn(key, d)
self.assertEqual(d[key], 'v%s' % key)
def testpopoldest(self):
d = util.lrucachedict(4)
d.insert('a', 'va', cost=10)
d.insert('b', 'vb', cost=5)
self.assertEqual(len(d), 2)
self.assertEqual(d.popoldest(), ('a', 'va'))
self.assertEqual(len(d), 1)
self.assertEqual(d.totalcost, 5)
self.assertEqual(d.popoldest(), ('b', 'vb'))
self.assertEqual(len(d), 0)
self.assertEqual(d.totalcost, 0)
self.assertIsNone(d.popoldest())
d['a'] = 'va'
d['b'] = 'vb'
d['c'] = 'vc'
d['d'] = 'vd'
self.assertEqual(d.popoldest(), ('a', 'va'))
self.assertEqual(len(d), 3)
for key in ('b', 'c', 'd'):
self.assertEqual(d[key], 'v%s' % key)
d['a'] = 'va'
self.assertEqual(d.popoldest(), ('b', 'vb'))
def testmaxcost(self):
# Item cost is zero by default.
d = util.lrucachedict(6, maxcost=10)
d['a'] = 'va'
d['b'] = 'vb'
d['c'] = 'vc'
d['d'] = 'vd'
self.assertEqual(len(d), 4)
self.assertEqual(d.totalcost, 0)
d.clear()
# Insertion to exact cost threshold works without eviction.
d.insert('a', 'va', cost=6)
d.insert('b', 'vb', cost=4)
self.assertEqual(len(d), 2)
self.assertEqual(d['a'], 'va')
self.assertEqual(d['b'], 'vb')
# Inserting a new element with 0 cost works.
d['c'] = 'vc'
self.assertEqual(len(d), 3)
# Inserting a new element with cost putting us above high
# water mark evicts oldest single item.
d.insert('d', 'vd', cost=1)
self.assertEqual(len(d), 3)
self.assertEqual(d.totalcost, 5)
self.assertNotIn('a', d)
for key in ('b', 'c', 'd'):
self.assertEqual(d[key], 'v%s' % key)
# Inserting a new element with enough room for just itself
# evicts all items before.
d.insert('e', 've', cost=10)
self.assertEqual(len(d), 1)
self.assertEqual(d.totalcost, 10)
self.assertIn('e', d)
# Inserting a new element with cost greater than threshold
# still retains that item.
d.insert('f', 'vf', cost=11)
self.assertEqual(len(d), 1)
self.assertEqual(d.totalcost, 11)
self.assertIn('f', d)
# Inserting a new element will evict the last item since it is
# too large.
d['g'] = 'vg'
self.assertEqual(len(d), 1)
self.assertEqual(d.totalcost, 0)
self.assertIn('g', d)
d.clear()
d.insert('a', 'va', cost=7)
d.insert('b', 'vb', cost=3)
self.assertEqual(len(d), 2)
# Replacing a value with smaller cost won't result in eviction.
d.insert('b', 'vb2', cost=2)
self.assertEqual(len(d), 2)
# Replacing a value with a higher cost will evict when threshold
# exceeded.
d.insert('b', 'vb3', cost=4)
self.assertEqual(len(d), 1)
self.assertNotIn('a', d)
def testmaxcostcomplex(self):
d = util.lrucachedict(100, maxcost=100)
d.insert('a', 'va', cost=9)
d.insert('b', 'vb', cost=21)
d.insert('c', 'vc', cost=7)
d.insert('d', 'vc', cost=50)
self.assertEqual(d.totalcost, 87)
# Inserting new element should free multiple elements so we hit
# low water mark.
d.insert('e', 'vd', cost=25)
self.assertEqual(len(d), 2)
self.assertNotIn('a', d)
self.assertNotIn('b', d)
self.assertNotIn('c', d)
self.assertIn('d', d)
self.assertIn('e', d)
if __name__ == '__main__':
silenttestrunner.main(__name__)