Pierre-Yves David <pierre-yves.david@ens-lyon.org> [Mon, 23 Dec 2013 15:29:51 -0800] rev 20207
obsolete: order of magnitude speedup in _computebumpedset
Reminder: a changeset is said "bumped" if it tries to obsolete a immutable
changeset.
The previous algorithm for computing bumped changeset was:
1) Get all public changesets
2) Find all they successors
3) Search for stuff that are eligible for being "bumped"
(mutable and non obsolete)
The entry size of this algorithm is `O(len(public))` which is mostly the same as
`O(len(repo))`. Even this this approach mean fewer obsolescence marker are
traveled, this is not very scalable.
The new algorithm is:
1) For each potential bumped changesets (non obsolete mutable)
2) iterate over precursors
3) if a precursors is public. changeset is bumped
We travel more obsolescence marker, but the entry size is much smaller since
the amount of potential bumped should remains mostly stable with time `O(1)`.
On some confidential gigantic repo this move bumped computation from 15.19s to
0.46s (×33 speedup…). On "smaller" repo (mercurial, cubicweb's review) no
significant gain were seen. The additional traversal of obsolescence marker is
probably probably counter balance the advantage of it.
Other optimisation could be done in the future (eg: sharing precursors cache
for divergence detection)
Pierre-Yves David <pierre-yves.david@ens-lyon.org> [Mon, 23 Dec 2013 13:36:13 -0800] rev 20206
obsolete: add an allprecursors method mirroring allsuccessors one.
Detection of bumped changeset should use `allprecursors(<mutable>)` instead or
`allsuccessors(<immutable>)` so we need the all precursors function to exists.
Pierre-Yves David <pierre-yves.david@ens-lyon.org> [Mon, 23 Dec 2013 16:04:51 -0800] rev 20205
perf: fix perfvolatilesets
The repoview's `filteredrevs` has been renamed to `filterrevs` at some point.
perf was never informed.