Mercurial > hg
changeset 39515:93486cc46125
treemanifest: introduce lazy loading of subdirs
An earlier patch series made it so that what to load was up to the calling code,
which works fine until manifests are copied - when they're copied, they're
loaded completely and thus we lose the entire benefit.
By lazy loading everything, we can avoid having to pass in the matcher to ~every
manifest function, and handle copies correctly as well. This changeset doesn't
go as far as it could with loading only the necessary subsets, that will happen
in later changes in this series; at the moment, except in a few situations, we
just load everything the moment we want to interact with treemanifest._dirs.
This is thus most likely to be a small slowdown if treemanifests is in use
regardless of whether narrow is in use, but hopefully easier to verify
correctness and review.
This is part of a series of speedups, it is not expected to produce any real speed
improvements itself, but the numbers show that it doesn't produce a large speed
penalty in any common case, and for the cases it does provide a penalty in, it
is not a large absolute amount (even if it is a large percentage amount).
Timing numbers according to command:
hyperfine --prepare <preparation_script> 'hg status'
HGRCPATH points to a file with the following contents:
[extensions]
narrow =
strip =
rebase =
mozilla-unified (called m-u below) was at revision #468856.
regular hash: eb39298e432d
treemanifests hash: 0553b7f29eaf
large-dir-repo (called l-d-r below) was generated with the following script:
#!/bin/bash
hg init large-dir-repo
mkdir -p large-dir-repo/third_party/rust/log
touch large-dir-repo/third_party/rust/log/foo.txt
for i in $(seq 1 30000); do
d=$(mktemp -d large-dir-repo/third_party/XXXXXXXXX)
touch $d/file.txt
done
hg -R large-dir-repo ci -Am 'rev0' --user test --date '0 0'
echo hi > large-dir-repo/third_party/rust/log/bar.txt
hg -R large-dir-repo ci -Am 'rev1' --user test --date '0 0'
echo hi > large-dir-repo/third_party/rust/log/baz.txt
hg -R large-dir-repo ci -Am 'rev2' --user test --date '0 0'
for the repos that use narrow, the narrowspec was this:
[include]
rootfilesin:accessible/jsat
rootfilesin:accessible/tests/mochitest/jsat
rootfilesin:mobile/android/chrome/content
rootfilesin:mobile/android/modules/geckoview
rootfilesin:third_party/rust/log
[exclude]
This narrowspec was chosen due to the size of the third_party/rust directory
(this directory was *not* modified in revision #468856 in mozilla-unified),
plus all the directories that *were* modified in revision #468856 of
mozilla-unified.
Importantly, when using narrow, these repos had everything checked out (in the
case of large-dir-repo, that means all 30,001 directories), *before* adding the
narrowspec. This is to simulate the behavior when using a virtual filesystem
that shows everything for the user even if they haven't added it to the
narrowspec yet. This is not a supported configuration, and `hg update` and `hg
rebase` will not really do the "correct" thing if there are mutations outside
of the narrowspec (which is not the case in these tests, due to a carefully
crafted narrowspec), but non-mutating commands should behave correctly.
I'm not claiming anything less than a 5% speed win as improvements due to this
change; these are probably eiter measurement artifacts or constant time
improvements. The numbers that aren't changing are shown primarily to prove that
this doesn't make anything worse in any case I plan on testing during this
series.
'before' is hg from commit 6268fed3
'N' indicates narrow in use
'T' indicates treemanifest in use
Please note that these commands and the narrowspec are a little different than
the ones in a similar table that I made in a3cabe9415e1.
Important: it is my understanding that these numbers below are *not super reliable*,
the large slowdowns may be artifacts of some odd interaction between GC and
python module/code complexity. Another changeset of mine (D4351) had shown large
timing differences when ~empty, uncalled functions were added to match.py,
though only when using --color=never or redirecting to /dev/null. We seem to be
on some cusp of complexity or code size that is causing, at my best guess
(according to linux `perf` benchmarks) GC to alter behavior and cause a
200-400ms difference in timings. I haven't had a chance to replicate these
results on another machine.
diff --git:
repo | N | T | before (mean +- stdev) | after (mean +- stdev) | % of before
------+---+---+------------------------+-----------------------+------------
m-u | | | 1.580 s +- 0.034 s | 1.576 s +- 0.022 s | 99.7%
m-u | | x | 1.568 s +- 0.025 s | 1.584 s +- 0.044 s | 101.0%
m-u | x | | 1.569 s +- 0.031 s | 1.554 s +- 0.025 s | 99.0%
m-u | x | x | 107.3 ms +- 1.6 ms | 106.3 ms +- 1.5 ms | 99.1%
l-d-r | | | 232.5 ms +- 5.9 ms | 233.5 ms +- 5.3 ms | 100.4%
l-d-r | | x | 236.6 ms +- 6.3 ms | 233.6 ms +- 7.0 ms | 98.7%
l-d-r | x | | 118.4 ms +- 2.1 ms | 118.4 ms +- 1.4 ms | 100.0%
l-d-r | x | x | 116.8 ms +- 1.5 ms | 118.9 ms +- 1.6 ms | 101.8%
diff -c . --git:
repo | N | T | before (mean +- stdev) | after (mean +- stdev) | % of before
------+---+---+------------------------+-----------------------+------------
m-u | | | 354.4 ms +- 16.6 ms | 351.0 ms +- 6.9 ms | 99.0%
m-u | | x | 207.2 ms +- 3.0 ms | 206.2 ms +- 2.7 ms | 99.5%
m-u | x | | 422.0 ms +- 26.0 ms | 351.2 ms +- 6.4 ms | 83.2% <--
m-u | x | x | 166.7 ms +- 2.1 ms | 169.5 ms +- 4.1 ms | 101.7%
l-d-r | | | 98.4 ms +- 4.5 ms | 98.5 ms +- 2.1 ms | 100.1%
l-d-r | | x | 5.519 s +- 0.060 s | 5.149 s +- 0.042 s | 93.3% <--
l-d-r | x | | 99.1 ms +- 3.2 ms | 102.6 ms +- 9.7 ms | 103.5% <--?
l-d-r | x | x | 994.9 ms +- 10.7 ms | 1.026 s +- 0.012 s | 103.1% <--?
rebase -r . --keep -d .^^:
repo | N | T | before (mean +- stdev) | after (mean +- stdev) | % of before
------+---+---+------------------------+-----------------------+------------
m-u | | | 6.639 s +- 0.168 s | 6.559 s +- 0.097 s | 98.8%
m-u | | x | 6.601 s +- 0.143 s | 6.640 s +- 0.207 s | 100.6%
m-u | x | | 6.582 s +- 0.098 s | 6.543 s +- 0.098 s | 99.4%
m-u | x | x | 678.4 ms +- 57.7 ms | 703.7 ms +- 52.4 ms | 103.7% <--?
l-d-r | | | 780.0 ms +- 23.9 ms | 776.0 ms +- 12.6 ms | 99.5%
l-d-r | | x | 7.520 s +- 0.255 s | 7.395 s +- 0.044 s | 98.3%
l-d-r | x | | 331.9 ms +- 16.5 ms | 327.0 ms +- 3.4 ms | 98.5%
l-d-r | x | x | 6.228 s +- 0.113 s | 5.924 s +- 0.044 s | 95.1%
status --change . --copies:
repo | N | T | before (mean +- stdev) | after (mean +- stdev) | % of before
------+---+---+------------------------+-----------------------+------------
m-u | | | 330.8 ms +- 7.2 ms | 329.0 ms +- 7.1 ms | 99.5%
m-u | | x | 182.9 ms +- 2.7 ms | 183.5 ms +- 2.7 ms | 100.3%
m-u | x | | 330.0 ms +- 7.6 ms | 327.1 ms +- 5.4 ms | 99.1%
m-u | x | x | 146.2 ms +- 2.4 ms | 147.1 ms +- 1.3 ms | 100.6%
l-d-r | | | 95.3 ms +- 1.4 ms | 95.9 ms +- 1.5 ms | 100.6%
l-d-r | | x | 5.157 s +- 0.035 s | 5.166 s +- 0.058 s | 100.2%
l-d-r | x | | 99.7 ms +- 3.0 ms | 100.2 ms +- 4.4 ms | 100.5%
l-d-r | x | x | 993.6 ms +- 13.1 ms | 1.025 s +- 0.015 s | 103.2% <--?
status --copies:
repo | N | T | before (mean +- stdev) | after (mean +- stdev) | % of before
------+---+---+------------------------+-----------------------+------------
m-u | | | 2.348 s +- 0.031 s | 2.329 s +- 0.019 s | 99.2%
m-u | | x | 2.337 s +- 0.026 s | 2.346 s +- 0.034 s | 100.4%
m-u | x | | 2.354 s +- 0.015 s | 2.342 s +- 0.021 s | 99.5%
m-u | x | x | 120.6 ms +- 4.3 ms | 119.2 ms +- 2.1 ms | 98.8%
l-d-r | | | 731.5 ms +- 11.1 ms | 719.6 ms +- 9.8 ms | 98.4%
l-d-r | | x | 729.0 ms +- 15.5 ms | 725.7 ms +- 10.6 ms | 99.5%
l-d-r | x | | 211.0 ms +- 3.9 ms | 212.8 ms +- 3.7 ms | 100.9%
l-d-r | x | x | 211.5 ms +- 4.2 ms | 211.0 ms +- 3.3 ms | 99.8%
update $rev^; ~/src/hg/hg{hg}/hg update $rev:
repo | N | T | before (mean +- stdev) | after (mean +- stdev) | % of before
------+---+---+------------------------+-----------------------+------------
m-u | | | 3.910 s +- 0.055 s | 3.920 s +- 0.075 s | 100.3%
m-u | | x | 3.613 s +- 0.056 s | 3.630 s +- 0.056 s | 100.5%
m-u | x | | 3.873 s +- 0.055 s | 3.864 s +- 0.049 s | 99.8%
m-u | x | x | 400.4 ms +- 7.4 ms | 403.6 ms +- 5.0 ms | 100.8%
l-d-r | | | 531.6 ms +- 10.0 ms | 528.8 ms +- 9.6 ms | 99.5%
l-d-r | | x | 10.377 s +- 0.049 s | 9.955 s +- 0.046 s | 95.9%
l-d-r | x | | 308.3 ms +- 4.4 ms | 306.8 ms +- 3.7 ms | 99.5%
l-d-r | x | x | 1.805 s +- 0.015 s | 1.834 s +- 0.020 s | 101.6%
Differential Revision: https://phab.mercurial-scm.org/D4366
author | spectral <spectral@google.com> |
---|---|
date | Thu, 16 Aug 2018 12:31:52 -0700 |
parents | b29ec19748a7 |
children | 079d7bfa463d |
files | mercurial/manifest.py |
diffstat | 1 files changed, 71 insertions(+), 6 deletions(-) [+] |
line wrap: on
line diff
--- a/mercurial/manifest.py Fri Sep 07 17:54:55 2018 -0400 +++ b/mercurial/manifest.py Thu Aug 16 12:31:52 2018 -0700 @@ -686,6 +686,7 @@ self._copyfunc = _noop self._dirty = False self._dirs = {} + self._lazydirs = {} # Using _lazymanifest here is a little slower than plain old dicts self._files = {} self._flags = {} @@ -699,9 +700,20 @@ def _subpath(self, path): return self._dir + path + def _loadalllazy(self): + for k, (path, node, readsubtree) in self._lazydirs.iteritems(): + self._dirs[k] = readsubtree(path, node) + self._lazydirs = {} + + def _loadlazy(self, d): + path, node, readsubtree = self._lazydirs[d] + self._dirs[d] = readsubtree(path, node) + del self._lazydirs[d] + def __len__(self): self._load() size = len(self._files) + self._loadalllazy() for m in self._dirs.values(): size += m.__len__() return size @@ -714,6 +726,7 @@ def _isempty(self): self._load() # for consistency; already loaded by all callers + self._loadalllazy() return (not self._files and (not self._dirs or all(m._isempty() for m in self._dirs.values()))) @@ -741,6 +754,7 @@ def iterentries(self): self._load() + self._loadalllazy() for p, n in sorted(itertools.chain(self._dirs.items(), self._files.items())): if p in self._files: @@ -751,6 +765,7 @@ def items(self): self._load() + self._loadalllazy() for p, n in sorted(itertools.chain(self._dirs.items(), self._files.items())): if p in self._files: @@ -763,6 +778,7 @@ def iterkeys(self): self._load() + self._loadalllazy() for p in sorted(itertools.chain(self._dirs, self._files)): if p in self._files: yield self._subpath(p) @@ -782,8 +798,12 @@ self._load() dir, subpath = _splittopdir(f) if dir: + if dir in self._lazydirs: + self._loadlazy(dir) + if dir not in self._dirs: return False + return self._dirs[dir].__contains__(subpath) else: return f in self._files @@ -792,6 +812,9 @@ self._load() dir, subpath = _splittopdir(f) if dir: + if dir in self._lazydirs: + self._loadlazy(dir) + if dir not in self._dirs: return default return self._dirs[dir].get(subpath, default) @@ -802,6 +825,9 @@ self._load() dir, subpath = _splittopdir(f) if dir: + if dir in self._lazydirs: + self._loadlazy(dir) + return self._dirs[dir].__getitem__(subpath) else: return self._files[f] @@ -810,11 +836,14 @@ self._load() dir, subpath = _splittopdir(f) if dir: + if dir in self._lazydirs: + self._loadlazy(dir) + if dir not in self._dirs: return '' return self._dirs[dir].flags(subpath) else: - if f in self._dirs: + if f in self._lazydirs or f in self._dirs: return '' return self._flags.get(f, '') @@ -822,6 +851,9 @@ self._load() dir, subpath = _splittopdir(f) if dir: + if dir in self._lazydirs: + self._loadlazy(dir) + return self._dirs[dir].find(subpath) else: return self._files[f], self._flags.get(f, '') @@ -830,6 +862,9 @@ self._load() dir, subpath = _splittopdir(f) if dir: + if dir in self._lazydirs: + self._loadlazy(dir) + self._dirs[dir].__delitem__(subpath) # If the directory is now empty, remove it if self._dirs[dir]._isempty(): @@ -845,6 +880,8 @@ self._load() dir, subpath = _splittopdir(f) if dir: + if dir in self._lazydirs: + self._loadlazy(dir) if dir not in self._dirs: self._dirs[dir] = treemanifest(self._subpath(dir)) self._dirs[dir].__setitem__(subpath, n) @@ -865,6 +902,8 @@ self._load() dir, subpath = _splittopdir(f) if dir: + if dir in self._lazydirs: + self._loadlazy(dir) if dir not in self._dirs: self._dirs[dir] = treemanifest(self._subpath(dir)) self._dirs[dir].setflag(subpath, flags) @@ -879,8 +918,12 @@ if self._copyfunc is _noop: def _copyfunc(s): self._load() - for d in self._dirs: - s._dirs[d] = self._dirs[d].copy() + # OPT: it'd be nice to not load everything here. Unfortunately + # this makes a mess of the "dirty" state tracking if we don't. + self._loadalllazy() + sdirs = s._dirs + for d, v in self._dirs.iteritems(): + sdirs[d] = v.copy() s._files = dict.copy(self._files) s._flags = dict.copy(self._flags) if self._loadfunc is _noop: @@ -904,6 +947,8 @@ return t1._load() t2._load() + t1._loadalllazy() + t2._loadalllazy() for d, m1 in t1._dirs.iteritems(): if d in t2._dirs: m2 = t2._dirs[d] @@ -929,10 +974,13 @@ self._load() topdir, subdir = _splittopdir(dir) if topdir: + if topdir in self._lazydirs: + self._loadlazy(topdir) if topdir in self._dirs: return self._dirs[topdir].hasdir(subdir) return False - return (dir + '/') in self._dirs + dirslash = dir + '/' + return dirslash in self._dirs or dirslash in self._lazydirs def walk(self, match): '''Generates matching file names. @@ -970,6 +1018,7 @@ # yield this dir's files and walk its submanifests self._load() + self._loadalllazy() for p in sorted(list(self._dirs) + list(self._files)): if p in self._files: fullp = self._subpath(p) @@ -1006,6 +1055,8 @@ if fn in self._flags: ret._flags[fn] = self._flags[fn] + # OPT: use visitchildrenset to avoid loading everything + self._loadalllazy() for dir, subm in self._dirs.iteritems(): m = subm._matches(match) if not m._isempty(): @@ -1041,6 +1092,9 @@ return t1._load() t2._load() + # OPT: do we need to load everything? + t1._loadalllazy() + t2._loadalllazy() for d, m1 in t1._dirs.iteritems(): m2 = t2._dirs.get(d, emptytree) _diff(m1, m2) @@ -1070,10 +1124,12 @@ return not self._dirty and not m2._dirty and self._node == m2._node def parse(self, text, readsubtree): + selflazy = self._lazydirs + subpath = self._subpath for f, n, fl in _parse(text): if fl == 't': f = f + '/' - self._dirs[f] = readsubtree(self._subpath(f), n) + selflazy[f] = (subpath(f), n, readsubtree) elif '/' in f: # This is a flat manifest, so use __setitem__ and setflag rather # than assigning directly to _files and _flags, so we can @@ -1100,9 +1156,11 @@ """ self._load() flags = self.flags + lazydirs = [(d[:-1], node, 't') for + d, (path, node, readsubtree) in self._lazydirs.iteritems()] dirs = [(d[:-1], self._dirs[d]._node, 't') for d in self._dirs] files = [(f, self._files[f], flags(f)) for f in self._files] - return _text(sorted(dirs + files)) + return _text(sorted(dirs + files + lazydirs)) def read(self, gettext, readsubtree): def _load_for_read(s): @@ -1115,6 +1173,11 @@ m1._load() m2._load() emptytree = treemanifest() + # OPT: Do we really need to load everything? Presumably things in lazy + # aren't dirty and don't need to be written. + self._loadalllazy() + m1._loadalllazy() + m2._loadalllazy() for d, subm in self._dirs.iteritems(): subp1 = m1._dirs.get(d, emptytree)._node subp2 = m2._dirs.get(d, emptytree)._node @@ -1134,6 +1197,8 @@ yield self self._load() + # OPT: use visitchildrenset to avoid loading everything. + self._loadalllazy() for d, subm in self._dirs.iteritems(): for subtree in subm.walksubtrees(matcher=matcher): yield subtree