getting garbage faster using FreeBSD?

Charles Shannon Hendrix shannon at
Sat Feb 24 00:30:37 UTC 2007

On Fri, 23 Feb 2007 12:46:19 -0800
Doug Barton <dougb at> wrote:

> Charles Shannon Hendrix wrote:
> > Sometimes I'll get good speed for awhile (seconds), and then it starts
> > slowing down or stopping.
> > 
> > /dev/random halts on me all the time.
> > 
> > FreeBSD 6.1 on SPARC64
> First, usual advice of upgrading to the latest -stable, second, what

If you mean -STABLE, no thanks.  This is a server, and I've never found
-STABLE to be stable.

> are the values of:
> sysctl kern.random

caesar# sysctl kern.random
kern.random.yarrow.gengateinterval: 10
kern.random.yarrow.bins: 10
kern.random.yarrow.fastthresh: 192
kern.random.yarrow.slowthresh: 256
kern.random.yarrow.slowoverthresh: 2
kern.random.sys.seeded: 1
kern.random.sys.harvest.ethernet: 1
kern.random.sys.harvest.point_to_point: 1
kern.random.sys.harvest.interrupt: 1
kern.random.sys.harvest.swi: 0

I manage to get a bursty 2.5MB/sec awhile ago.  Bursty meaning periods of
reading and long pauses where reads block.

The hardware is a Sun Ultra 2, dual 300MHz CPUs.

2.5MB/sec would be fine for most of my uses if it were steady.  The problem
is the long pauses where I get 0MB/sec.

For example, when I'm streaming an encrypted backup over the net from this
machine, it would be nice if /dev/random I/O didn't cause any pauses.

Most of the time it doesn't affect much, but it seems like this machine
shouldn't have such a slow /dev/random, and I thought the new code didn't
block in any case.

shannon           | The trade of governing has always been monopolized by the
                  | most ignorant and the most rascally individuals of
                  | mankind.  
                  |        -- Thomas Paine

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