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view tests/test-narrow-update.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 | 351cbda889db |
children | ccd76e292be5 |
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$ . "$TESTDIR/narrow-library.sh" create full repo $ hg init master $ cd master $ echo init > init $ hg ci -Aqm 'initial' $ mkdir inside $ echo inside > inside/f1 $ mkdir outside $ echo outside > outside/f1 $ hg ci -Aqm 'add inside and outside' $ echo modified > inside/f1 $ hg ci -qm 'modify inside' $ echo modified > outside/f1 $ hg ci -qm 'modify outside' $ cd .. $ hg clone --narrow ssh://user@dummy/master narrow --include inside requesting all changes adding changesets adding manifests adding file changes added 4 changesets with 2 changes to 1 files new changesets *:* (glob) updating to branch default 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ cd narrow $ hg debugindex -c rev linkrev nodeid p1 p2 0 0 9958b1af2add 000000000000 000000000000 1 1 2db4ce2a3bfe 9958b1af2add 000000000000 2 2 0980ee31a742 2db4ce2a3bfe 000000000000 3 3 4410145019b7 0980ee31a742 000000000000 $ hg update -q 0 Can update to revision with changes inside $ hg update -q 'desc("add inside and outside")' $ hg update -q 'desc("modify inside")' $ find * inside inside/f1 $ cat inside/f1 modified Can update to revision with changes outside $ hg update -q 'desc("modify outside")' $ find * inside inside/f1 $ cat inside/f1 modified Can update with a deleted file inside $ hg rm inside/f1 $ hg update -q 'desc("modify inside")' $ hg update -q 'desc("modify outside")' $ hg update -q 'desc("initial")' $ hg update -q 'desc("modify inside")' Can update with a moved file inside $ hg mv inside/f1 inside/f2 $ hg update -q 'desc("modify outside")' $ hg update -q 'desc("add inside and outside")' $ hg update -q 'desc("modify inside")'