Re: File System Performance

[Mike Fedyk]

On Mon, Nov 12, 2001 at 12:59:54PM -0700, Richard Gooch wrote:
> Here's an idea: add a "--compact" option to tar, so that it creates
> *all* inodes (files and directories alike) in the base directory, and
> then renames newly created entries to shuffle them into their correct
> positions. That should limit the number of block groups that are used,
> right?
> 
> It would probably also be a good idea to do that for cp as well, so
> that when I do a "cp -al" of a virgin kernel tree, I can keep all the
> directory inodes together. It will make a cold diff even faster.
> 

I don't think that would help at all... With the current file/dir allocator
it will choose a new block group for each directory no matter what the
parent is...

The new allocator would spread them accross the different block groups only
if they are created *directly* off of the root of the FS. Your idea would
make things worse for the new allocator *if* the tree is uncompressed into
the root of the FS, and *no* difference if not...

Mike