Mercurial > hg
view tests/test-simplemerge.py @ 51681:522b4d729e89
mmap: populate the mapping by default
Without pre-population, accessing all data through a mmap can result in many
pagefault, reducing performance significantly. If the mmap is prepopulated, the
performance can no longer get slower than a full read.
(See benchmark number below)
In some cases were very few data is read, prepopulating can be overkill and
slower than populating on access (through page fault). So that behavior can be
controlled when the caller can pre-determine the best behavior.
(See benchmark number below)
In addition, testing with populating in a secondary thread yield great result
combining the best of each approach. This might be implemented in later
changesets.
In all cases, using mmap has a great effect on memory usage when many processes
run in parallel on the same machine.
### Benchmarks
# What did I run
A couple of month back I ran a large benchmark campaign to assess the impact of
various approach for using mmap with the revlog (and other files), it
highlighted a few benchmarks that capture the impact of the changes well. So to
validate this change I checked the following:
- log command displaying various revisions
(read the changelog index)
- log command displaying the patch of listed revisions
(read the changelog index, the manifest index and a few files indexes)
- unbundling a few revisions
(read and write changelog, manifest and few files indexes, and walk the graph
to update some cache)
- pushing a few revisions
(read and write changelog, manifest and few files indexes, walk the graph to
update some cache, performs various accesses locally and remotely during
discovery)
Benchmarks were run using the default module policy (c+py) and the rust one. No
significant difference were found between the two implementation, so we will
present result using the default policy (unless otherwise specified).
I ran them on a few repositories :
- mercurial: a "public changeset only" copy of mercurial from 2018-08-01 using
zstd compression and sparse-revlog
- pypy: a copy of pypy from 2018-08-01 using zstd compression and sparse-revlog
- netbeans: a copy of netbeans from 2018-08-01 using zstd compression and
sparse-revlog
- mozilla-try: a copy of mozilla-try from 2019-02-18 using zstd compression and
sparse-revlog
- mozilla-try persistent-nodemap: Same as the above but with a persistent
nodemap. Used for the log --patch benchmark only
# Results
For the smaller repositories (mercurial, pypy), the impact of mmap is almost
imperceptible, other cost dominating the operation. The impact of prepopulating
is undiscernible in the benchmark we ran.
For larger repositories the benchmark support explanation given above:
On netbeans, the log can be about 1% faster without repopulation (for a
difference < 100ms) but unbundle becomes a bit slower, even when small.
### data-env-vars.name = netbeans-2018-08-01-zstd-sparse-revlog
# benchmark.name = hg.command.unbundle
# benchmark.variants.issue6528 = disabled
# benchmark.variants.reuse-external-delta-parent = yes
# benchmark.variants.revs = any-1-extra-rev
# benchmark.variants.source = unbundle
# benchmark.variants.verbosity = quiet
with-populate: 0.240157
no-populate: 0.265087 (+10.38%, +0.02)
# benchmark.variants.revs = any-100-extra-rev
with-populate: 1.459518
no-populate: 1.481290 (+1.49%, +0.02)
## benchmark.name = hg.command.push
# benchmark.variants.explicit-rev = none
# benchmark.variants.issue6528 = disabled
# benchmark.variants.protocol = ssh
# benchmark.variants.reuse-external-delta-parent = yes
# benchmark.variants.revs = any-1-extra-rev
with-populate: 0.771919
no-populate: 0.792025 (+2.60%, +0.02)
# benchmark.variants.revs = any-100-extra-rev
with-populate: 1.459518
no-populate: 1.481290 (+1.49%, +0.02)
For mozilla-try, the "slow down" from pre-populate for small `hg log` is more
visible, but still small in absolute time. (using rust value for the persistent
nodemap value to be relevant).
### data-env-vars.name = mozilla-try-2019-02-18-ds2-pnm
# benchmark.name = hg.command.log
# bin-env-vars.hg.flavor = rust
# benchmark.variants.patch = yes
# benchmark.variants.limit-rev = 1
with-populate: 0.237813
no-populate: 0.229452 (-3.52%, -0.01)
# benchmark.variants.limit-rev = 10
# benchmark.variants.patch = yes
with-populate: 1.213578
no-populate: 1.205189
### data-env-vars.name = mozilla-try-2019-02-18-zstd-sparse-revlog
# benchmark.variants.limit-rev = 1000
# benchmark.variants.patch = no
# benchmark.variants.rev = tip
with-populate: 0.198607
no-populate: 0.195038 (-1.80%, -0.00)
However pre-populating provide a significant boost on more complex operations
like unbundle or push:
### data-env-vars.name = mozilla-try-2019-02-18-zstd-sparse-revlog
# benchmark.name = hg.command.push
# benchmark.variants.explicit-rev = none
# benchmark.variants.issue6528 = disabled
# benchmark.variants.protocol = ssh
# benchmark.variants.reuse-external-delta-parent = yes
# benchmark.variants.revs = any-1-extra-rev
with-populate: 4.798632
no-populate: 4.953295 (+3.22%, +0.15)
# benchmark.variants.revs = any-100-extra-rev
with-populate: 4.903618
no-populate: 5.014963 (+2.27%, +0.11)
## benchmark.name = hg.command.unbundle
# benchmark.variants.revs = any-1-extra-rev
with-populate: 1.423411
no-populate: 1.585365 (+11.38%, +0.16)
# benchmark.variants.revs = any-100-extra-rev
with-populate: 1.537909
no-populate: 1.688489 (+9.79%, +0.15)
author | Pierre-Yves David <pierre-yves.david@octobus.net> |
---|---|
date | Thu, 11 Apr 2024 00:02:07 +0200 |
parents | 6000f5b25c9b |
children | 493034cc3265 |
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# Copyright (C) 2004, 2005 Canonical Ltd # # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 2 of the License, or # (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program; if not, see <http://www.gnu.org/licenses/>. import unittest from mercurial import ( error, simplemerge, util, ) from mercurial.utils import stringutil TestCase = unittest.TestCase # bzr compatible interface, for the tests class Merge3(simplemerge.Merge3Text): """3-way merge of texts. Given BASE, OTHER, THIS, tries to produce a combined text incorporating the changes from both BASE->OTHER and BASE->THIS. All three will typically be sequences of lines.""" def __init__(self, base, a, b): basetext = b'\n'.join([i.strip(b'\n') for i in base] + [b'']) atext = b'\n'.join([i.strip(b'\n') for i in a] + [b'']) btext = b'\n'.join([i.strip(b'\n') for i in b] + [b'']) if ( stringutil.binary(basetext) or stringutil.binary(atext) or stringutil.binary(btext) ): raise error.Abort(b"don't know how to merge binary files") simplemerge.Merge3Text.__init__( self, basetext, atext, btext, base, a, b ) def split_lines(t): return util.stringio(t).readlines() ############################################################ # test case data from the gnu diffutils manual # common base TZU = split_lines( b""" The Nameless is the origin of Heaven and Earth; The named is the mother of all things. Therefore let there always be non-being, so we may see their subtlety, And let there always be being, so we may see their outcome. The two are the same, But after they are produced, they have different names. They both may be called deep and profound. Deeper and more profound, The door of all subtleties! """ ) LAO = split_lines( b""" The Way that can be told of is not the eternal Way; The name that can be named is not the eternal name. The Nameless is the origin of Heaven and Earth; The Named is the mother of all things. Therefore let there always be non-being, so we may see their subtlety, And let there always be being, so we may see their outcome. The two are the same, But after they are produced, they have different names. """ ) TAO = split_lines( b""" The Way that can be told of is not the eternal Way; The name that can be named is not the eternal name. The Nameless is the origin of Heaven and Earth; The named is the mother of all things. Therefore let there always be non-being, so we may see their subtlety, And let there always be being, so we may see their result. The two are the same, But after they are produced, they have different names. -- The Way of Lao-Tzu, tr. Wing-tsit Chan """ ) MERGED_RESULT = split_lines( b"""\ The Way that can be told of is not the eternal Way; The name that can be named is not the eternal name. The Nameless is the origin of Heaven and Earth; The Named is the mother of all things. Therefore let there always be non-being, so we may see their subtlety, And let there always be being, so we may see their result. The two are the same, But after they are produced, they have different names.\ \n<<<<<<< LAO\ \n======= -- The Way of Lao-Tzu, tr. Wing-tsit Chan \ \n>>>>>>> TAO """ ) class TestMerge3(TestCase): def log(self, msg): pass def test_no_changes(self): """No conflicts because nothing changed""" m3 = Merge3([b'aaa', b'bbb'], [b'aaa', b'bbb'], [b'aaa', b'bbb']) self.assertEqual( list(m3.find_sync_regions()), [(0, 2, 0, 2, 0, 2), (2, 2, 2, 2, 2, 2)], ) self.assertEqual(list(m3.merge_regions()), [(b'unchanged', 0, 2)]) self.assertEqual( list(m3.merge_groups()), [(b'unchanged', [b'aaa', b'bbb'])] ) def test_front_insert(self): m3 = Merge3([b'zz'], [b'aaa', b'bbb', b'zz'], [b'zz']) # todo: should use a sentinel at end as from get_matching_blocks # to match without zz self.assertEqual( list(m3.find_sync_regions()), [(0, 1, 2, 3, 0, 1), (1, 1, 3, 3, 1, 1)], ) self.assertEqual( list(m3.merge_regions()), [(b'a', 0, 2), (b'unchanged', 0, 1)] ) self.assertEqual( list(m3.merge_groups()), [(b'a', [b'aaa', b'bbb']), (b'unchanged', [b'zz'])], ) def test_null_insert(self): m3 = Merge3([], [b'aaa', b'bbb'], []) # todo: should use a sentinel at end as from get_matching_blocks # to match without zz self.assertEqual(list(m3.find_sync_regions()), [(0, 0, 2, 2, 0, 0)]) self.assertEqual(list(m3.merge_regions()), [(b'a', 0, 2)]) self.assertEqual( simplemerge.render_minimized(m3), ([b'aaa', b'bbb'], False) ) def test_no_conflicts(self): """No conflicts because only one side changed""" m3 = Merge3( [b'aaa', b'bbb'], [b'aaa', b'111', b'bbb'], [b'aaa', b'bbb'] ) self.assertEqual( list(m3.find_sync_regions()), [(0, 1, 0, 1, 0, 1), (1, 2, 2, 3, 1, 2), (2, 2, 3, 3, 2, 2)], ) self.assertEqual( list(m3.merge_regions()), [(b'unchanged', 0, 1), (b'a', 1, 2), (b'unchanged', 1, 2)], ) def test_append_a(self): m3 = Merge3( [b'aaa\n', b'bbb\n'], [b'aaa\n', b'bbb\n', b'222\n'], [b'aaa\n', b'bbb\n'], ) self.assertEqual( b''.join(simplemerge.render_minimized(m3)[0]), b'aaa\nbbb\n222\n' ) def test_append_b(self): m3 = Merge3( [b'aaa\n', b'bbb\n'], [b'aaa\n', b'bbb\n'], [b'aaa\n', b'bbb\n', b'222\n'], ) self.assertEqual( b''.join(simplemerge.render_minimized(m3)[0]), b'aaa\nbbb\n222\n' ) def test_append_agreement(self): m3 = Merge3( [b'aaa\n', b'bbb\n'], [b'aaa\n', b'bbb\n', b'222\n'], [b'aaa\n', b'bbb\n', b'222\n'], ) self.assertEqual( b''.join(simplemerge.render_minimized(m3)[0]), b'aaa\nbbb\n222\n' ) def test_append_clash(self): m3 = Merge3( [b'aaa\n', b'bbb\n'], [b'aaa\n', b'bbb\n', b'222\n'], [b'aaa\n', b'bbb\n', b'333\n'], ) ml, conflicts = simplemerge.render_minimized( m3, name_a=b'a', name_b=b'b', start_marker=b'<<', mid_marker=b'--', end_marker=b'>>', ) self.assertEqual( b''.join(ml), b'aaa\n' b'bbb\n' b'<< a\n' b'222\n' b'--\n' b'333\n' b'>> b\n', ) def test_insert_agreement(self): m3 = Merge3( [b'aaa\n', b'bbb\n'], [b'aaa\n', b'222\n', b'bbb\n'], [b'aaa\n', b'222\n', b'bbb\n'], ) ml, conflicts = simplemerge.render_minimized( m3, name_a=b'a', name_b=b'b', start_marker=b'<<', mid_marker=b'--', end_marker=b'>>', ) self.assertEqual(b''.join(ml), b'aaa\n222\nbbb\n') def test_insert_clash(self): """Both try to insert lines in the same place.""" m3 = Merge3( [b'aaa\n', b'bbb\n'], [b'aaa\n', b'111\n', b'bbb\n'], [b'aaa\n', b'222\n', b'bbb\n'], ) self.assertEqual( list(m3.find_sync_regions()), [(0, 1, 0, 1, 0, 1), (1, 2, 2, 3, 2, 3), (2, 2, 3, 3, 3, 3)], ) self.assertEqual( list(m3.merge_regions()), [ (b'unchanged', 0, 1), (b'conflict', 1, 1, 1, 2, 1, 2), (b'unchanged', 1, 2), ], ) self.assertEqual( list(m3.merge_groups()), [ (b'unchanged', [b'aaa\n']), (b'conflict', ([], [b'111\n'], [b'222\n'])), (b'unchanged', [b'bbb\n']), ], ) ml, conflicts = simplemerge.render_minimized( m3, name_a=b'a', name_b=b'b', start_marker=b'<<', mid_marker=b'--', end_marker=b'>>', ) self.assertEqual( b''.join(ml), b'''aaa << a 111 -- 222 >> b bbb ''', ) def test_replace_clash(self): """Both try to insert lines in the same place.""" m3 = Merge3( [b'aaa', b'000', b'bbb'], [b'aaa', b'111', b'bbb'], [b'aaa', b'222', b'bbb'], ) self.assertEqual( list(m3.find_sync_regions()), [(0, 1, 0, 1, 0, 1), (2, 3, 2, 3, 2, 3), (3, 3, 3, 3, 3, 3)], ) def test_replace_multi(self): """Replacement with regions of different size.""" m3 = Merge3( [b'aaa', b'000', b'000', b'bbb'], [b'aaa', b'111', b'111', b'111', b'bbb'], [b'aaa', b'222', b'222', b'222', b'222', b'bbb'], ) self.assertEqual( list(m3.find_sync_regions()), [(0, 1, 0, 1, 0, 1), (3, 4, 4, 5, 5, 6), (4, 4, 5, 5, 6, 6)], ) def test_merge_poem(self): """Test case from diff3 manual""" m3 = Merge3(TZU, LAO, TAO) ml, conflicts = simplemerge.render_minimized(m3, b'LAO', b'TAO') self.log(b'merge result:') self.log(b''.join(ml)) self.assertEqual(ml, MERGED_RESULT) def test_binary(self): with self.assertRaises(error.Abort): Merge3([b'\x00'], [b'a'], [b'b']) def test_dos_text(self): base_text = b'a\r\n' this_text = b'b\r\n' other_text = b'c\r\n' m3 = Merge3( base_text.splitlines(True), other_text.splitlines(True), this_text.splitlines(True), ) m_lines, conflicts = simplemerge.render_minimized(m3, b'OTHER', b'THIS') self.assertEqual( b'<<<<<<< OTHER\r\nc\r\n=======\r\nb\r\n' b'>>>>>>> THIS\r\n'.splitlines(True), m_lines, ) def test_mac_text(self): base_text = b'a\r' this_text = b'b\r' other_text = b'c\r' m3 = Merge3( base_text.splitlines(True), other_text.splitlines(True), this_text.splitlines(True), ) m_lines, conflicts = simplemerge.render_minimized(m3, b'OTHER', b'THIS') self.assertEqual( b'<<<<<<< OTHER\rc\r=======\rb\r' b'>>>>>>> THIS\r'.splitlines(True), m_lines, ) if __name__ == '__main__': import silenttestrunner silenttestrunner.main(__name__)