Re: [Gnu-arch-users] Re: tla on nfs only

[Aaron Bentley]

Stefan Monnier wrote:
> I don't understand what you're talking about.
> We need:
> - one stat per work-tree file.
> - compare this result with a known value (which can come from the
>   work-tree's inode-sigs or from the rev-lib).

Those are the requirements for determining whether the file's contents 
have changed.

For determining whether the file's metadata (permissions, file type) has 
changed, the requirements are:
- one stat of the file in the working directory
- one stat of the file in the reference tree

An optimization I made was to reuse the stats from metadata checks in 
the file contents check.

> I can't see any reason why it would be faster than using the worktree's
> inode-sigs.

It's {three integer comparisons} instead of a {map lookup followed by 
string comparison}.  Since the reference tree stat is necessary for 
other reasons, it's very cheap.

Aaron
--
Aaron Bentley
Director of Information Technology
Panometrics, Inc.