Re: AS/400 tuning question

[Pete Hall <pbhall@xxxxxxxxxx>]

At 17:00 06/24/2000 , Joe Teff wrote:
>I have not done any real AS/400 tuning for a couple of years and I've never
>tuned one of the server models. A friend asked me today if tuning a server
>model was any different than a regular model and I couldn't answer him.
>Other than looking for a blue stripe, I'm not sure if I could even identify a
>server model. I know that their is a governor of some type that punishes
>interactive jobs. Is that done with software in OS? Will it stop you from
>allocating more memory to certain subsystems or setting high priorities to
>interactive jobs. TIA.

All I can tell you is that based on my recent experience with tuning and 
S30, and later a 730 (we upgraded the S30), there is no difference. I 
watched IBM install the governor during the upgrade. At least on a 730, I 
don't think it has anything to do with interactive vs batch load. It is a 
hardware device that communicates with the CPU, and it determines the 
processor feature code. Without it, the processor doesn't function at all. 
My subjective impression is that there is definitely an improvement in 
throughput in batch as opposed to doing the same things interactively, but 
I can't guess why this would be. I have never observed the cycle gobbling 
behavior that many complained about when the server models were first 
introduced. My theory is that IBM yielded to customer pressure and no 
longer enforces interactive limitations by running jobs that eat CPU 
cycles. You can control memory pools and priorities on server models just 
as you can on any other AS/400.


Pete Hall
pbhall@execpc.com
http://www.execpc.com/~pbhall
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