rust: hooking into Python code
We introduce a new class called 'rustlazyancestors'
in the ancestors module, which is used only if
parsers.rustlazyancestors does exist.
The implementation of __contains__ stays unchanged,
but is now backed by the Rust iterator. It would
probably be a good candidate for further development,
though, as it is mostly looping, and duplicates the
'seen' set.
The Rust code could be further optimized, however it already
gives rise to performance improvements:
median timing from hg perfancestors:
- on pypy:
before: 0.077566s
after: 0.016676s -79%
- on mozilla central:
before: 0.190037s
after: 0.082225s -58%
- on a private repository (about one million revisions):
before: 0.567085s
after: 0.108816s -80%
- on another private repository (about 400 000 revisions):
before: 1.440918s
after: 0.290116s -80%
median timing for hg perfbranchmap base
- on pypy:
before: 1.383413s
after: 0.507993s -63%
- on mozilla central:
before: 2.821940s
after: 1.258902s -55%
- on a private repository (about one million revisions):
before: 77.065076s
after: 16.158475s -80%
- on another private repository (about 401 000 revisions):
before: 7.835503s
after: 3.545331s -54%
A new repository uses zlib storage, which doesn't need a requirement
$ hg init default
$ cd default
$ cat .hg/requires
dotencode
fncache
generaldelta
revlogv1
store
testonly-simplestore (reposimplestore !)
$ touch foo
$ hg -q commit -A -m 'initial commit with a lot of repeated repeated repeated text to trigger compression'
$ hg debugrevlog -c | grep 0x78
0x78 (x) : 1 (100.00%)
0x78 (x) : 110 (100.00%)
$ cd ..
Unknown compression engine to format.compression aborts
$ hg --config experimental.format.compression=unknown init unknown
abort: compression engine unknown defined by experimental.format.compression not available
(run "hg debuginstall" to list available compression engines)
[255]
A requirement specifying an unknown compression engine results in bail
$ hg init unknownrequirement
$ cd unknownrequirement
$ echo exp-compression-unknown >> .hg/requires
$ hg log
abort: repository requires features unknown to this Mercurial: exp-compression-unknown!
(see https://mercurial-scm.org/wiki/MissingRequirement for more information)
[255]
$ cd ..
#if zstd
$ hg --config experimental.format.compression=zstd init zstd
$ cd zstd
$ cat .hg/requires
dotencode
exp-compression-zstd
fncache
generaldelta
revlogv1
store
testonly-simplestore (reposimplestore !)
$ touch foo
$ hg -q commit -A -m 'initial commit with a lot of repeated repeated repeated text'
$ hg debugrevlog -c | grep 0x28
0x28 : 1 (100.00%)
0x28 : 98 (100.00%)
$ cd ..
Specifying a new format.compression on an existing repo won't introduce data
with that engine or a requirement
$ cd default
$ touch bar
$ hg --config experimental.format.compression=zstd -q commit -A -m 'add bar with a lot of repeated repeated repeated text'
$ cat .hg/requires
dotencode
fncache
generaldelta
revlogv1
store
testonly-simplestore (reposimplestore !)
$ hg debugrevlog -c | grep 0x78
0x78 (x) : 2 (100.00%)
0x78 (x) : 199 (100.00%)
#endif