Mercurial > hg
view tests/test-contrib-dumprevlog.t @ 42743:8c9a6adec67a
rust-discovery: using the children cache in add_missing
The DAG range computation often needs to get back to very old
revisions, and turns out to be disproportionately long, given
that the end goal is to remove the descendents of the given
missing revisons from the undecided set.
The fast iteration capabilities available in the Rust case make
it possible to avoid the DAG range entirely, at the cost of
precomputing the children cache, and to simply iterate on
children of the given missing revisions.
This is a case where staying on the same side of the interface
between the two languages has clear benefits.
On discoveries with initial undecided sets
small enough to bypass sampling entirely, the total cost of
computing the children cache and the subsequent iteration
becomes better than the Python + C counterpart, which relies on
reachableroots2.
For example, on a repo with more than one million revisions with
an initial undecided set of 11 elements, we get these figures:
Rust version with simple iteration
addcommons: 57.287us
first undecided computation: 184.278334ms
first children cache computation: 131.056us
addmissings iteration: 42.766us
first addinfo total: 185.24 ms
Python + C version
first addcommons: 0.29 ms
addcommons 0.21 ms
first undecided computation 191.35 ms
addmissings 45.75 ms
first addinfo total: 237.77 ms
On discoveries with large undecided sets, the initial price paid
makes the first addinfo slower than the Python + C version,
but that's more than compensated by the gain in sampling and
subsequent iterations.
Here's an extreme example with an undecided set of a million revisions:
Rust version:
first undecided computation: 293.842629ms
first children cache computation: 407.911297ms
addmissings iteration: 34.312869ms
first addinfo total: 776.02 ms
taking initial sample
query 2: sampling time: 1318.38 ms
query 2; still undecided: 1005013, sample size is: 200
addmissings: 143.062us
Python + C version:
first undecided computation 298.13 ms
addmissings 80.13 ms
first addinfo total: 399.62 ms
taking initial sample
query 2: sampling time: 3957.23 ms
query 2; still undecided: 1005013, sample size is: 200
addmissings 52.88 ms
Differential Revision: https://phab.mercurial-scm.org/D6428
author | Georges Racinet <georges.racinet@octobus.net> |
---|---|
date | Tue, 16 Apr 2019 01:16:39 +0200 |
parents | 5abc47d4ca6b |
children | 2f2682f40ea0 |
line wrap: on
line source
#require reporevlogstore $ CONTRIBDIR="$TESTDIR/../contrib" $ hg init repo-a $ cd repo-a $ echo this is file a > a $ hg add a $ hg commit -m first $ echo adding to file a >> a $ hg commit -m second $ echo adding more to file a >> a $ hg commit -m third $ hg verify checking changesets checking manifests crosschecking files in changesets and manifests checking files checked 3 changesets with 3 changes to 1 files Dumping revlog of file a to stdout: $ "$PYTHON" "$CONTRIBDIR/dumprevlog" .hg/store/data/a.i file: .hg/store/data/a.i node: 183d2312b35066fb6b3b449b84efc370d50993d0 linkrev: 0 parents: 0000000000000000000000000000000000000000 0000000000000000000000000000000000000000 length: 15 -start- this is file a -end- node: b1047953b6e6b633c0d8197eaa5116fbdfd3095b linkrev: 1 parents: 183d2312b35066fb6b3b449b84efc370d50993d0 0000000000000000000000000000000000000000 length: 32 -start- this is file a adding to file a -end- node: 8c4fd1f7129b8cdec6c7f58bf48fb5237a4030c1 linkrev: 2 parents: b1047953b6e6b633c0d8197eaa5116fbdfd3095b 0000000000000000000000000000000000000000 length: 54 -start- this is file a adding to file a adding more to file a -end- Dump all revlogs to file repo.dump: $ find .hg/store -name "*.i" | sort | xargs "$PYTHON" "$CONTRIBDIR/dumprevlog" > ../repo.dump $ cd .. Undumping into repo-b: $ hg init repo-b $ cd repo-b $ "$PYTHON" "$CONTRIBDIR/undumprevlog" < ../repo.dump .hg/store/00changelog.i .hg/store/00manifest.i .hg/store/data/a.i $ cd .. Rebuild fncache with clone --pull: $ hg clone --pull -U repo-b repo-c requesting all changes adding changesets adding manifests adding file changes added 3 changesets with 3 changes to 1 files new changesets de1da620e7d8:46946d278c50 Verify: $ hg -R repo-c verify checking changesets checking manifests crosschecking files in changesets and manifests checking files checked 3 changesets with 3 changes to 1 files Compare repos: $ hg -R repo-c incoming repo-a comparing with repo-a searching for changes no changes found [1] $ hg -R repo-a incoming repo-c comparing with repo-c searching for changes no changes found [1]