RE: Does jBoss work on iSeries?

["Nathan M. Andelin" <nandel@xxxxxxxxxxxxxxxxxxx>]

David,

I think you need to take into account that threads under OS/400 have
processor "affinity", meaning that once a thread is dispatched to a
processor, it tends to remain associated with that processor, to avoid cache
reloading.  Several good sources say that cache reloading can have a severe,
negative impact on performance.  EJB architecture offers a means of
dispatching workload to other processors, even on one box.

Say a Servlet receives a request to summarize sales by state and display the
results.  The process of summarizing sales by state may be a fairly CPU
intensive activity that needs to be synchronized per user.  Using EJBs,
summarizing sales by state might be dispatched to one processor, while
generating the HTML might be dispatched to another, so that when multiple
requests are received at the same time, the 2nd isn't waiting for the 1st to
complete.

I agree completely that distributed architectures under J2EE have costs and
problems associated with them, but what is the alternative when CPU
intensive workloads are involved?

Nathan.



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message: 6
date: Mon, 08 Mar 2004 14:46:09 -0700
from: "David Morris" <David.Morris@xxxxxxxxxxxxx>
subject: RE: Does jBoss work on iSeries?

Nathan,

The current upper limit for the iSeries of 32 processors/256G main memory is
likely to meet most needs business needs. There are a lot of costs in a
distributed application and those costs are often overlooked. A single
system is much simpler whether it is an iSeries or other server has few
points of failure, is much easier to test, and can take full advantage of
native data access.