Re: 3x slower file reading oddity

[dean gaudet]

On Mon, 17 Jun 2002, Andrew Morton wrote:

> I rather depends on what is in /tmp/filelist.  I assume it's
> something like the output of `find'.  And I assume you're
> using ext2 or ext3?

yup: find mail1 mail2 -type f -print0 >/tmp/filelist

ext3.

thanks for the description of the block groups... that all makes more
sense now.

> You'll get best throughput with a single read thread.

what if you have a disk array with lots of spindles?  it seems at some
point that you need to give the array or some lower level driver a lot of
i/os to choose from so that it can get better parallelism out of the
hardware.

i see similar slowdowns on a 4-IDE-disk softRAID5+LVM+ext3 setup (SMP
2.4.19-pre7-ac4).  not nearly as bad as on the single disk.

-dean