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
$ echo "[extensions]" >> $HGRCPATH
$ echo "share = " >> $HGRCPATH
prepare repo1
$ hg init repo1
$ cd repo1
$ echo a > a
$ hg commit -A -m'init'
adding a
share it
$ cd ..
$ hg share repo1 repo2
updating working directory
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
share shouldn't have a store dir
$ cd repo2
$ test -d .hg/store
[1]
$ hg root -Tjson | sed 's|\\\\|\\|g'
[
{
"hgpath": "$TESTTMP/repo2/.hg",
"reporoot": "$TESTTMP/repo2",
"storepath": "$TESTTMP/repo1/.hg/store"
}
]
share shouldn't have a full cache dir, original repo should
$ hg branches
default 0:d3873e73d99e
$ hg tags
tip 0:d3873e73d99e
$ test -d .hg/cache
[1]
$ ls -1 .hg/wcache || true
checkisexec (execbit !)
checklink (symlink !)
checklink-target (symlink !)
manifestfulltextcache (reporevlogstore !)
$ ls -1 ../repo1/.hg/cache
branch2-served
rbc-names-v1
rbc-revs-v1
tags2-visible
Some sed versions appends newline, some don't, and some just fails
$ cat .hg/sharedpath; echo
$TESTTMP/repo1/.hg
trailing newline on .hg/sharedpath is ok
$ hg tip -q
0:d3873e73d99e
$ echo '' >> .hg/sharedpath
$ cat .hg/sharedpath
$TESTTMP/repo1/.hg
$ hg tip -q
0:d3873e73d99e
commit in shared clone
$ echo a >> a
$ hg commit -m'change in shared clone'
check original
$ cd ../repo1
$ hg log
changeset: 1:8af4dc49db9e
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: change in shared clone
changeset: 0:d3873e73d99e
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: init
$ hg update
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cat a # should be two lines of "a"
a
a
commit in original
$ echo b > b
$ hg commit -A -m'another file'
adding b
check in shared clone
$ cd ../repo2
$ hg log
changeset: 2:c2e0ac586386
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: another file
changeset: 1:8af4dc49db9e
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: change in shared clone
changeset: 0:d3873e73d99e
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: init
$ hg update
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cat b # should exist with one "b"
b
hg serve shared clone
$ hg serve -n test -p $HGPORT -d --pid-file=hg.pid
$ cat hg.pid >> $DAEMON_PIDS
$ get-with-headers.py localhost:$HGPORT 'raw-file/'
200 Script output follows
-rw-r--r-- 4 a
-rw-r--r-- 2 b
Cloning a shared repo via bundle2 results in a non-shared clone
$ cd ..
$ hg clone -q --stream --config ui.ssh="\"$PYTHON\" \"$TESTDIR/dummyssh\"" ssh://user@dummy/`pwd`/repo2 cloned-via-bundle2
$ cat ./cloned-via-bundle2/.hg/requires | grep "shared"
[1]
$ hg id --cwd cloned-via-bundle2 -r tip
c2e0ac586386 tip
$ cd repo2
test unshare command
$ hg unshare
$ test -d .hg/store
$ test -f .hg/sharedpath
[1]
$ grep shared .hg/requires
[1]
$ hg unshare
abort: this is not a shared repo
[255]
check that a change does not propagate
$ echo b >> b
$ hg commit -m'change in unshared'
$ cd ../repo1
$ hg id -r tip
c2e0ac586386 tip
$ cd ..
non largefiles repos won't enable largefiles
$ hg share --config extensions.largefiles= repo2 sharedrepo
The fsmonitor extension is incompatible with the largefiles extension and has been disabled. (fsmonitor !)
The fsmonitor extension is incompatible with the largefiles extension and has been disabled. (fsmonitor !)
updating working directory
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ [ -f sharedrepo/.hg/hgrc ]
[1]
test shared clones using relative paths work
$ mkdir thisdir
$ hg init thisdir/orig
$ hg share -U thisdir/orig thisdir/abs
$ hg share -U --relative thisdir/abs thisdir/rel
$ cat thisdir/rel/.hg/sharedpath
../../orig/.hg (no-eol)
$ grep shared thisdir/*/.hg/requires
thisdir/abs/.hg/requires:shared
thisdir/rel/.hg/requires:relshared
thisdir/rel/.hg/requires:shared
test that relative shared paths aren't relative to $PWD
$ cd thisdir
$ hg -R rel root
$TESTTMP/thisdir/rel
$ cd ..
now test that relative paths really are relative, survive across
renames and changes of PWD
$ hg -R thisdir/abs root
$TESTTMP/thisdir/abs
$ hg -R thisdir/rel root
$TESTTMP/thisdir/rel
$ mv thisdir thatdir
$ hg -R thatdir/abs root
abort: .hg/sharedpath points to nonexistent directory $TESTTMP/thisdir/orig/.hg!
[255]
$ hg -R thatdir/rel root
$TESTTMP/thatdir/rel
test unshare relshared repo
$ cd thatdir/rel
$ hg unshare
$ test -d .hg/store
$ test -f .hg/sharedpath
[1]
$ grep shared .hg/requires
[1]
$ hg unshare
abort: this is not a shared repo
[255]
$ cd ../..
$ rm -r thatdir
Demonstrate buggy behavior around requirements validation
See comment in localrepo.py:makelocalrepository() for more.
$ hg init sharenewrequires
$ hg share sharenewrequires shareoldrequires
updating working directory
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cat >> sharenewrequires/.hg/requires << EOF
> missing-requirement
> EOF
We cannot open the repo with the unknown requirement
$ hg -R sharenewrequires status
abort: repository requires features unknown to this Mercurial: missing-requirement!
(see https://mercurial-scm.org/wiki/MissingRequirement for more information)
[255]
BUG: we don't get the same error when opening the shared repo pointing to it
$ hg -R shareoldrequires status
Explicitly kill daemons to let the test exit on Windows
$ killdaemons.py