Hammer: Low interactivity during high filesystem activity

[Matthew Dillon]

:Hi,
:
:Just noticed while running blogbench on my hammer partition, that "top"
:in another window took several seconds (around 10) to show up. The same
:happened for "man". I have a dual core Athlon X2, and I don't see heavy
:CPU load. As I am accessing the box over SSH (nfe0), could that be the
:potential bottleneck?
:
:Regards,
:
:   Michael

    This is simply because blogbench's memory load is paging other
    processes out and when you start something new it has to page it
    back in, which takes a while due to all the disk activity.

    The blog# on the left represents the size of the data set.  The
    data set is ever-increasing and at some point, depending on how
    much memory you have, the data set blows out the system caches.
    HAMMER has a tendancy to be able to write more then UFS so HAMMER
    tends to blow out the system's data caches sooner.  At that point
    the disk is being thrashed badly... that's part of what is being tested.

					-Matt
					Matthew Dillon 
					<dillon at backplane.com>