GELI strangeness with gstat

[Pete French]

So, I have a set of machines running rul disc
encryption with GELI. The output from gstat on
an example one looks something like this:

   0     27      3    100    0.4     16    100    0.1    1.1| ada0p4
   0     27      3    100    0.9     16    100    0.2    1.3| ada0p4.eli

I uapgraded a couple of thme to much faster CPUs - the output then
started looking like this:

   0    146      0      0    0.0    125    604    0.1    5.7| ada0p4
   2    146      0      0    0.0    125    604    0.1  104.3| ada0p4.eli

...so the .eli device is now running at 100% despite
the underlying disc only being about 6% busy.

This was software encryption - my assumption was that the faster COU's
were now enabling me to overload the encryption somehow, so I enabled
AES-NI on the COU. Now I have hardware encryption. But the output from gstat
still looks the same.

Whats going on here ? Its very ouzzlking. What is even odder is that these
machines are ina HAST pair, and the secondary side looks fine - i.e. only
a few percent busy on the disc and the encrypted device. If I sap
roles then the efect persists - the HAST primary has a massively busy
ELI device.

I realise the oprimary will be doing reads as well as writes, but as you can
see from the snapshot above, its not singificany compares to the
writes, and the effect is also ther when the load is dominated by writes.

I am teoprted to think that gstat is being screwy here, but it bothers me not
knowing (especially as I am trying to tarck diwn bottlenecks in the system),

Anyone got any opinions on what might be showing up here ?

-pete.