nodemap: introduce an option to use mmap to read the nodemap mapping
The performance and memory benefit is much greater if we don't have to copy all
the data in memory for each information. So we introduce an option (on by
default) to read the data using mmap.
This changeset is the last one definition the API for index support nodemap
data. (they have to be able to use the mmaping).
Below are some benchmark comparing the best we currently have in 5.3 with the
final step of this series (using the persistent nodemap implementation in
Rust). The benchmark run `hg perfindex` with various revset and the following
variants:
Before:
* do not use the persistent nodemap
* use the CPython implementation of the index for nodemap
* use mmapping of the changelog index
After:
* use the MixedIndex Rust code, with the NodeTree object for nodemap access
(still in review)
* use the persistent nodemap data from disk
* access the persistent nodemap data through mmap
* use mmapping of the changelog index
The persistent nodemap greatly speed up most operation on very large
repositories. Some of the previously very fast lookup end up a bit slower because
the persistent nodemap has to be setup. However the absolute slowdown is very
small and won't matters in the big picture.
Here are some numbers (in seconds) for the reference copy of mozilla-try:
Revset Before After abs-change speedup
-10000: 0.004622 0.005532 0.000910 × 0.83
-10: 0.000050 0.000132 0.000082 × 0.37
tip 0.000052 0.000085 0.000033 × 0.61
0 + (-10000:) 0.028222 0.005337 -0.022885 × 5.29
0 0.023521 0.000084 -0.023437 × 280.01
(-10000:) + 0 0.235539 0.005308 -0.230231 × 44.37
(-10:) + :9 0.232883 0.000180 -0.232703 ×1293.79
(-10000:) + (:99) 0.238735 0.005358 -0.233377 × 44.55
:99 + (-10000:) 0.317942 0.005593 -0.312349 × 56.84
:9 + (-10:) 0.313372 0.000179 -0.313193 ×1750.68
:9 0.316450 0.000143 -0.316307 ×2212.93
On smaller repositories, the cost of nodemap related operation is not as big, so
the win is much more modest. Yet it helps shaving a handful of millisecond here
and there.
Here are some numbers (in seconds) for the reference copy of mercurial:
Revset Before After abs-change speedup
-10: 0.000065 0.000097 0.000032 × 0.67
tip 0.000063 0.000078 0.000015 × 0.80
0 0.000561 0.000079 -0.000482 × 7.10
-10000: 0.004609 0.003648 -0.000961 × 1.26
0 + (-10000:) 0.005023 0.003715 -0.001307 × 1.35
(-10:) + :9 0.002187 0.000108 -0.002079 ×20.25
(-10000:) + 0 0.006252 0.003716 -0.002536 × 1.68
(-10000:) + (:99) 0.006367 0.003707 -0.002660 × 1.71
:9 + (-10:) 0.003846 0.000110 -0.003736 ×34.96
:9 0.003854 0.000099 -0.003755 ×38.92
:99 + (-10000:) 0.007644 0.003778 -0.003866 × 2.02
Differential Revision: https://phab.mercurial-scm.org/D7894
$ cat >> $HGRCPATH <<EOF
> [extensions]
> convert=
> [convert]
> hg.saverev=False
> EOF
$ hg init orig
$ cd orig
$ echo foo > foo
$ echo bar > bar
$ hg ci -qAm 'add foo bar' -d '0 0'
$ echo >> foo
$ hg ci -m 'change foo' -d '1 0'
$ hg up -qC 0
$ hg copy --after --force foo bar
$ hg copy foo baz
$ hg ci -m 'make bar and baz copies of foo' -d '2 0'
created new head
Test that template can print all file copies (issue4362)
$ hg log -r . --template "{file_copies % ' File: {file_copy}\n'}"
File: bar (foo)
File: baz (foo)
$ hg bookmark premerge1
$ hg merge -r 1
merging baz and foo to baz
1 files updated, 1 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg ci -m 'merge local copy' -d '3 0'
$ hg up -C 1
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
(leaving bookmark premerge1)
$ hg bookmark premerge2
$ hg merge 2
merging foo and baz to baz
1 files updated, 1 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg ci -m 'merge remote copy' -d '4 0'
created new head
Make and delete some tags
$ hg tag that
$ hg tag --remove that
$ hg tag this
#if execbit
$ chmod +x baz
#else
$ echo some other change to make sure we get a rev 5 > baz
#endif
$ hg ci -m 'mark baz executable' -d '5 0'
$ cd ..
$ hg convert --datesort orig new 2>&1 | grep -v 'subversion python bindings could not be loaded'
initializing destination new repository
scanning source...
sorting...
converting...
8 add foo bar
7 change foo
6 make bar and baz copies of foo
5 merge local copy
4 merge remote copy
3 Added tag that for changeset 88586c4e9f02
2 Removed tag that
1 Added tag this for changeset c56a7f387039
0 mark baz executable
updating bookmarks
$ cd new
$ hg out ../orig
comparing with ../orig
searching for changes
no changes found
[1]
#if execbit
$ hg bookmarks
premerge1 3:973ef48a98a4
premerge2 8:91d107c423ba
#else
Different hash because no x bit
$ hg bookmarks
premerge1 3:973ef48a98a4
premerge2 8:3537b15eaaca
#endif
Test that redoing a convert results in an identical graph
$ cd ../
$ rm new/.hg/shamap
$ hg convert --datesort orig new 2>&1 | grep -v 'subversion python bindings could not be loaded'
scanning source...
sorting...
converting...
8 add foo bar
7 change foo
6 make bar and baz copies of foo
5 merge local copy
4 merge remote copy
3 Added tag that for changeset 88586c4e9f02
2 Removed tag that
1 Added tag this for changeset c56a7f387039
0 mark baz executable
updating bookmarks
$ hg -R new log -G -T '{rev} {desc}'
o 8 mark baz executable
|
o 7 Added tag this for changeset c56a7f387039
|
o 6 Removed tag that
|
o 5 Added tag that for changeset 88586c4e9f02
|
o 4 merge remote copy
|\
+---o 3 merge local copy
| |/
| o 2 make bar and baz copies of foo
| |
o | 1 change foo
|/
o 0 add foo bar
check shamap LF and CRLF handling
$ cat > rewrite.py <<EOF
> import sys
> # Interlace LF and CRLF
> lines = [(l.rstrip() + ((i % 2) and b'\n' or b'\r\n'))
> for i, l in enumerate(open(sys.argv[1], 'rb'))]
> open(sys.argv[1], 'wb').write(b''.join(lines))
> EOF
$ "$PYTHON" rewrite.py new/.hg/shamap
$ cd orig
$ hg up -qC 1
$ echo foo >> foo
$ hg ci -qm 'change foo again'
$ hg up -qC 2
$ echo foo >> foo
$ hg ci -qm 'change foo again again'
$ cd ..
$ hg convert --datesort orig new 2>&1 | grep -v 'subversion python bindings could not be loaded'
scanning source...
sorting...
converting...
1 change foo again again
0 change foo again
updating bookmarks
init broken repository
$ hg init broken
$ cd broken
$ echo a >> a
$ echo b >> b
$ hg ci -qAm init
$ echo a >> a
$ echo b >> b
$ hg copy b c
$ hg ci -qAm changeall
$ hg up -qC 0
$ echo bc >> b
$ hg ci -m changebagain
created new head
$ HGMERGE=internal:local hg -q merge
$ hg ci -m merge
$ hg mv b d
$ hg ci -m moveb
break it
#if reporevlogstore
$ rm .hg/store/data/b.*
#endif
#if reposimplestore
$ rm .hg/store/data/b/*
#endif
$ cd ..
$ hg --config convert.hg.ignoreerrors=True convert broken fixed
initializing destination fixed repository
scanning source...
sorting...
converting...
4 init
ignoring: data/b.i@1e88685f5dde: no match found (reporevlogstore !)
ignoring: data/b/index@1e88685f5dde: no node (reposimplestore !)
3 changeall
2 changebagain
1 merge
0 moveb
$ hg -R fixed verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
checked 5 changesets with 5 changes to 3 files
manifest -r 0
$ hg -R fixed manifest -r 0
a
manifest -r tip
$ hg -R fixed manifest -r tip
a
c
d
$ cd ..
$ hg init commit-references
$ cd commit-references
$ echo a > a
$ hg ci -Aqm initial
$ echo b > b
$ hg ci -Aqm 'the previous commit was 1451231c8757'
$ echo c > c
$ hg ci -Aqm 'the working copy is called ffffffffffff'
$ cd ..
$ hg convert commit-references new-commit-references -q \
> --config convert.hg.sourcename=yes
$ cd new-commit-references
$ hg log -T '{node|short} {desc}\n'
fe295c9e6bc6 the working copy is called ffffffffffff
642508659503 the previous commit was c2491f685436
c2491f685436 initial