Re: [Ext2-devel] disk throughput

Alex Bligh - linux-kernel
2001-11-05T09:59:15Z

I think I was slightly too brief:

> --On Monday, 05 November, 2001 12:54 AM -0500 "Albert D. Cahalan"
> <acahalan@cs.uml.edu> wrote:
>
>> By putting directories far apart, you leave room for regular
>> files (added at some future time) to be packed close together.
>
> Mmmm... but if you read ahead your directories (see lkml passim)
> I'd be prepared to be the gain here is either minimized, or
> negative.

IE if you put in code to queue a cache a subdirectory when it's
entry in the parent is enumerated (either in userland or
in kernelland), then you get far less seeking as it all
comes 'up front' and the seeks can be monotonic. However,
still the closer the directories are, the better.

But more to the point, if your directories tend to be cached
this way, you surely win by having the directories allocated
the same way as files (i.e. to be packed /all/ close together).

--
Alex Bligh