[Gnu-arch-users] Re: readdir() optimization for ext3/Linux 2.6

[Miles Bader]

Florian Weimer <address@hidden> writes:
> > Isn't this filesystem-specific?  How on earth do you tell what sorting
> > order is best for a given directory?!?
> 
> There's a real degradation only for file systems which issue random
> inode numbers which are in no way correlated with disk locations.

I seem to recall that reiserfs in particular was very picky in some
cases about what order you did things in.  I'm not even sure if
reiserfs uses inodes at all in the same sense traditional unix FSs do.

I'm not sure if it affects this case though -- the context in which I
saw this was Hans Reiser complaining about a `unpack a tar file'
benchmark, saying it was only fair if the given tar file was also
created on reiserfs, because then it would use the optimal file ordering
chosen by the fs, or something like that (I though it was a pretty
stupid complaint actually).

> We could call statfs() and check for the file system type, either for
> each directory or once for the project root.

That doesn't sound very nice unless there are clearly only a few easily
identifiable cases...

-Miles
-- 
`To alcohol!  The cause of, and solution to,
 all of life's problems' --Homer J. Simpson