Mercurial > hg
view tests/test-convert-cvsnt-mergepoints.rlog @ 17970:0b03454abae7
ancestor: faster algorithm for difference of ancestor sets
One of the major reasons rebase is slow in large repositories is
the computation of the detach set: the set of ancestors of the
changesets to rebase not in the destination parent. This is currently
done via a revset that does two walks all the way to the root of
the DAG. Instead of doing that, to find ancestors of a set <revs>
not in another set <common> we walk up the tree in reverse revision
number order, maintaining sets of nodes visited from <revs>, <common>
or both.
For the common case where the sets are close both topologically and
in revision number (relative to repository size), this has been
found to speed up rebase by around 15-20%. When the nodes are farther
apart and the DAG is highly branching, it is harder to say which
would win.
Here's how long computing the detach set takes in a linear repository
with over 400000 changesets, rebasing near tip:
Rebasing across 4 changesets
Revset method: 2.2s
New algorithm: 0.00015s
Rebasing across 250 changesets
Revset method: 2.2s
New algorithm: 0.00069s
Rebasing across 10000 changesets
Revset method: 2.4s
New algorithm: 0.019s
author | Siddharth Agarwal <sid0@fb.com> |
---|---|
date | Mon, 26 Nov 2012 11:46:51 -0800 |
parents | 727f7aaefaab |
children |
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head: 1.2 branch: locks: strict access list: symbolic names: MYBRANCH1_2: 1.1.2.2.0.2 MYBRANCH1_1: 1.1.0.4 MYBRANCH1: 1.1.0.2 keyword substitution: kv total revisions: 8; selected revisions: 8 description: ---------------------------- revision 1.2 date: 2009/04/02 07:00:32; author: user; state: Exp; lines: +1 -1; kopt: kv; commitid: 14d449d462903487; mergepoint: 1.1.2.2.2.1; filename: foo.txt; merge ---------------------------- revision 1.1 date: 2009/04/02 06:50:43; author: user; state: Exp; kopt: kv; commitid: 17ac49d460432d04; filename: foo.txt; branches: 1.1.2; 1.1.4; foo.txt ---------------------------- revision 1.1.4.2 date: 2009/04/02 07:02:51; author: user; state: Exp; lines: +1 -0; kopt: kv; commitid: 170049d4631b364d; mergepoint: 1.1.2.2; filename: foo.txt; merge ---------------------------- revision 1.1.4.1 date: 2009/04/02 06:53:42; author: user; state: Exp; lines: +1 -1; kopt: kv; commitid: dc849d460f52f49; filename: foo.txt; quux ---------------------------- revision 1.1.2.2 date: 2009/04/02 06:53:20; author: user; state: Exp; lines: +1 -1; kopt: kv; commitid: 8ec49d460e02f04; filename: foo.txt; branches: 1.1.2.2.2; baz ---------------------------- revision 1.1.2.1 date: 2009/04/02 06:52:38; author: user; state: Exp; lines: +1 -1; kopt: kv; commitid: d5049d460b62e7b; filename: foo.txt; bar ---------------------------- revision 1.1.2.2.2.1 date: 2009/04/02 06:55:42; author: user; state: Exp; lines: +1 -1; kopt: kv; commitid: 11c849d4616d30d1; filename: foo.txt; bazzie =============================================================================