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view tests/test-issue1175.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 | 3a7efcbdf288 |
children | 3df0bd706c40 |
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https://bz.mercurial-scm.org/1175 $ hg init $ touch a $ hg ci -Am0 adding a $ hg mv a a1 $ hg ci -m1 $ hg co 0 1 files updated, 0 files merged, 1 files removed, 0 files unresolved $ hg mv a a2 $ hg up note: possible conflict - a was renamed multiple times to: a1 a2 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg ci -m2 $ touch a $ hg ci -Am3 adding a $ hg mv a b $ hg ci -Am4 a $ hg ci --debug --traceback -Am5 b committing files: b warning: can't find ancestor for 'b' copied from 'a'! committing manifest committing changelog updating the branch cache committed changeset 5:83a687e8a97c80992ba385bbfd766be181bfb1d1 $ hg verify checking changesets checking manifests crosschecking files in changesets and manifests checking files checked 6 changesets with 4 changes to 4 files $ hg export --git tip # HG changeset patch # User test # Date 0 0 # Thu Jan 01 00:00:00 1970 +0000 # Node ID 83a687e8a97c80992ba385bbfd766be181bfb1d1 # Parent 1d1625283f71954f21d14c3d44d0ad3c019c597f 5 diff --git a/b b/b new file mode 100644 https://bz.mercurial-scm.org/show_bug.cgi?id=4476 $ hg init foo $ cd foo $ touch a && hg ci -Aqm a $ hg mv a b $ echo b1 >> b $ hg ci -Aqm b1 $ hg up 0 1 files updated, 0 files merged, 1 files removed, 0 files unresolved $ hg mv a b $ echo b2 >> b $ hg ci -Aqm b2 $ hg graft 1 grafting 1:5974126fad84 "b1" merging b warning: conflicts while merging b! (edit, then use 'hg resolve --mark') abort: unresolved conflicts, can't continue (use 'hg resolve' and 'hg graft --continue') [255] $ echo a > b $ echo b3 >> b $ hg resolve --mark b (no more unresolved files) continue: hg graft --continue $ hg graft --continue grafting 1:5974126fad84 "b1" warning: can't find ancestor for 'b' copied from 'a'! $ hg log -f b -T 'changeset: {rev}:{node|short}\nsummary: {desc}\n\n' changeset: 3:376d30ccffc0 summary: b1 changeset: 2:416baaa2e5e4 summary: b2 changeset: 0:3903775176ed summary: a