[Ext2-devel] Re: [RFC] mke2fs with DIR_INDEX, RESIZE_INODE by default

[Arjan van de Ven]

> In general, I doubt directory readahead actually buys you *that* much,
> because most workloads follow up the readdir with a stat() or an
> open() call for each file returned, or something which requires
> reading in the inode.  In addition, it's rare that the directory will
> be contiguously allocated, which also cuts down on the value of the
> readahead.

what it buys you shows up on raid1 I suppose... while disk 0 is doing
the head seek for the stat/open, disk1 is doing the head seek for the
next directory entry.... so I can see that being a big gain in that
specific circumstance.