Re: What's cooking in git.git (Aug 2018, #04; Fri, 17)

> * nd/unpack-trees-with-cache-tree (2018-08-13) 5 commits
>  - unpack-trees: reuse (still valid) cache-tree from src_index
>  - unpack-trees: reduce malloc in cache-tree walk
>  - unpack-trees: optimize walking same trees with cache-tree
>  - unpack-trees: add performance tracing
>  - trace.h: support nested performance tracing
>
>  The unpack_trees() API used in checking out a branch and merging
>  walks one or more trees along with the index.  When the cache-tree
>  in the index tells us that we are walking a tree whose flattened
>  contents is known (i.e. matches a span in the index), as linearly
>  scanning a span in the index is much more efficient than having to
>  open tree objects recursively and listing their entries, the walk
>  can be optimized, which is done in this topic.
>
>  Will merge to and cook in 'next'.