[Jfs-discussion] why so much iowait time in JFS?

[huanghua <hua...@tu...>]

I did all the test in fedora RC1 ,originally with kernel 2.6.1,
but I upgrade it to kernel 2.6.4



I have a partition on my hard disk /dev/hda3, and I mkfs.jfs on it.
I created 500,000 files on it and then removed them all.
This create process took me about 230 seconds and the remove process
took me about 200 seconds.

At the second, I wanted to do it again, that is creating 500,000 files
and then removing them.
But this time with the command 'top' I found there was almoust 100%
iowait cpu. So
I will take me extrodinariy time to finish it.
why? Who konws why?
Why at the second time, there is so much iowait time?