performance: speedup computation of extinct revisions
In their current state, revset calls can be very costly, as we test
predicates on the entire repository.
This change drops revset calls in favor of direct testing of the phase
of changesets.
Performance test on my Mercurial checkout
- 19857 total changesets,
- 1584 obsolete changesets,
- 13310 obsolescence markers.
Before:
! extinct
! wall 0.015124
After:
! extinct
! wall 0.009424
Performance test on a Mozilla central checkout:
- 117293 total changesets,
- 1 obsolete changeset,
- 1 obsolescence marker.
Before:
! extinct
! wall 0.032844
After:
! extinct
! wall 0.000066
requesting all changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 4 changes to 4 files
updating to branch default
4 files updated, 0 files merged, 0 files removed, 0 files unresolved
requesting all changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 4 changes to 4 files
updating to branch default
4 files updated, 0 files merged, 0 files removed, 0 files unresolved