Rick Stevens wrote:
> 4) I don't know if the fact that the process runing at 100%
of one CPU
> means it is compute bound. Looking at the disk I/O meter in
> gkrellm I see bursts of writes followed by intervals of no
> transfer. I know that magnetic reorientation requires some time
> to "set" and that may be why the delays are there. Or it may be
> compute bound.
Run "top" and you may find that the shred process is in a "D" state
lot of the time. That means it's in an I/O wait state, waiting on the
drive to complete some operation. A "D" state can suck up a lot of CPU.
Thanks Rick. It's in "D" state only about 5-10% of the time. Yet
disk writes are occuring (according to the spikes and numbers in
gkrellm) for 1 second or so, every 2 seconds. So that either points
to random number computation or the wait needed to let the new
magnetic orientation 'set'. Not sure.