I/O or Threading Suffer

[Mark Murray]

Robert Watson writes:
> On Tue, 20 Jul 2004, Scott Long wrote:
> 
> > If you are dd'ing from /dev/random, then you are depleting the entropy
> > pool.  Anything else that tries to get random numbers is going to block
> > in strange ways.  Trying just dd'ing from /dev/zero and see if that
> > makes a difference. 
> 
> With Yarrow, /dev/random should just keep on chugging, so this is unlikely
> to be the source.  However, lots of /dev/random I/O may take a while to
> yield if it's working hard in kernel, so if that is combined with a
> scheduling nit of some sort, we could be looking at a starvation issue.

When you read /dev/random, you only exercise the output generator, and this
is a pretty simple piece of code.

Yarrow's kernel thread is used ONLY for the entropy harvesting, and is only
indirectly coupled to the output generator.

M
--
Mark Murray
iumop ap!sdn w,I idlaH