tree 4e1319d834e128e9375dac563db2a87f9776da58
parent 9200e4a97b6e051dd56d3de5378febae40a367e9
author Han-Wen Nienhuys <hanwen@google.com> 1467982574 +0200
committer Han-Wen Nienhuys <hanwen@google.com> 1468234494 +0200

Parallelize slothfs-populate.

* Walk R/W, new R/O and old R/O tree in parallel.

* Within a tree walk, do each repository in parallel. This also
  cleans up the tree construction as a side effect.

* Check inode identity to avoid a costly XAttr lookup.

Test data for AOSP:
  Before: 90 seconds.
  After : 15 seconds

Change-Id: If0c8c8b05d7fb9cf81f382153c8c53e10ae1e086