[PATCH v2] unpack-trees: avoid duplicate ODB lookups during checkout

From: Jeff Hostetler <jeffhost@microsoft.com>

Version 2 simplifies this and just copies the tree_descriptor data and borrows the underlying buffer without mallocing. It also handles the n=3 cases, so merges shold be helped too.

I've updated the p0004 perf times in the commit message. The V2 changes took ~0.15 off the V1 times. The total reduction is ~1 second.

================ Avoid duplicate ODB lookups for trees during traverse_tree_recursive().

Jeff Hostetler (1):
  unpack-trees: avoid duplicate ODB lookups during checkout

 unpack-trees.c | 23 +++++++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)