Re: [Gnu-arch-users] [PATCH] arch speedups on big trees

[Tom Lord]

    > From: Chris Mason <address@hidden>

    > snapping the inode sig is pretty expensive right now,

It would be helpful to know why.

For a tagline tree using mostly embedded tags, it should be little
more than the cost of a traversal plus the cost of writing the
signature file.

As I said, for a tree using lots of _explicit_ tags, you currently
have to add in the cost of reading all of the .id files, roughly twice
each.

The existing inode signature/id-cache optimizations can be generalized
to avoid having to read all of those .id files.

My best guess continues to be that you want to generalize the existing
optimizations that way first (to avoid reading .id files), before
worrying too much about eliminating traversals or whether or not it's
possible/practical to do partial traversals.


-t