Mercurial > hg
view tests/test-merge-symlinks.t @ 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 | f2719b387380 |
children | b6776b34e44e |
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$ cat > echo.py <<EOF > #!/usr/bin/env python > import os, sys > try: > import msvcrt > msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY) > msvcrt.setmode(sys.stderr.fileno(), os.O_BINARY) > except ImportError: > pass > > for k in ('HG_FILE', 'HG_MY_ISLINK', 'HG_OTHER_ISLINK', 'HG_BASE_ISLINK'): > print k, os.environ[k] > EOF Create 2 heads containing the same file, once as a file, once as a link. Bundle was generated with: # hg init t # cd t # echo a > a # hg ci -qAm t0 -d '0 0' # echo l > l # hg ci -qAm t1 -d '1 0' # hg up -C 0 # ln -s a l # hg ci -qAm t2 -d '2 0' # echo l2 > l2 # hg ci -qAm t3 -d '3 0' $ hg init t $ cd t $ hg -q pull "$TESTDIR/bundles/test-merge-symlinks.hg" $ hg up -C 3 3 files updated, 0 files merged, 0 files removed, 0 files unresolved Merge them and display *_ISLINK vars merge heads $ hg merge --tool="python ../echo.py" merging l HG_FILE l HG_MY_ISLINK 1 HG_OTHER_ISLINK 0 HG_BASE_ISLINK 0 0 files updated, 1 files merged, 0 files removed, 0 files unresolved (branch merge, don't forget to commit) Test working directory symlink bit calculation wrt copies, especially on non-supporting systems. merge working directory $ hg up -C 2 1 files updated, 0 files merged, 1 files removed, 0 files unresolved $ hg copy l l2 $ HGMERGE="python ../echo.py" hg up 3 merging l2 HG_FILE l2 HG_MY_ISLINK 1 HG_OTHER_ISLINK 0 HG_BASE_ISLINK 0 0 files updated, 1 files merged, 0 files removed, 0 files unresolved $ cd ..