WIll using a multiprocessor system improve DSC Tag Engine performance?

We are developing a multiple workstation vacuum chamber automation control application using the DSC.
The chambers under control each have a set of process controllers (Opto22 "Ultimate Brains") running the fundamental interlock and process mechanisms via their own software. The brains are set up for communication via OPC, thus LabVIEW can monitor the IO states of the system as well as variable values in the brain software via DSC tags. In addition, LV can manipulate variables to make requests that the brain software branch to different subroutines. The other ("control") workstations in the system pass requests to the brains via the software on the monitoring workstation, so as to ensure that requests are enqueued properly.
The problem is at this point there are 1300 tags configured for the DSC, and the workstation responsible for monitoring them shows near 100% CPU load all the time; most of that taken by the DSC Engine. This is with only half of the final project's chambers installed and active. As a result, it sometimes takes several attempts for a control workstation to successfully pass a request to the brains via the monitoring workstation.
We are concerned that performance will only worsen as we bring the additional chambers online.
Would adding a second processor to the workstation improve performance? If dual processors would help, would additional processors help more?
Note: we are examining which tags we monitor all the time and are going to try to reduce that list to those tags critical for normal operation, with an option to temporarily expand monitoring to the larger list for debugging purposes. I am concerned that even if that helps now, the problem will get worse again as we bring additional components on line. Is it the sheer number of tags defined for the DSC engine that gates the load on the engine, or the number that we are actively reading with our program?
Thanks for any illumination you can offer.
Kevin R
Kevin Roche
Advisory Engineer/Scientist
Spintronics and Magnetoelectronics group
IBM Research Almaden

I have a partial answer. We've swapped in the dual processor machine and see some improvement. The processor load was still hovering around 100%, though.
More importantly, we think we've learned something about how the DSC engine is actually working. The monitoring workstation not only runs the DSC engine to trade data with the other workstations, but an OPC server to handle transactions with the "brains". So any requests for data from the brains really are routed via the monitoring workstation.
We had built one common tag database because we thought that would simplify programming. We did some tests today, however, and discovered that if we stop the tag engines on the control workstations, processor load drops dramatically on the monitoring workstation.
What we've realized is that apparently if a read tag exists in a machine's database, the DSC fetches its value, regardless of whether our LabVIEW software ever actually uses the value. We deleted most of the brain tags from the control workstation databases, leaving only the LV memory tags and the few brain tags actually used by our vis. So now the monitoring workstation is not being asked to query those 1000 tags by 3 different tag engines, only by the one using it.
CPU load is down to about 73% now (because the monitoring workstation is still itself watching those 1000 tags). That's still high, but we have a better idea what is going on.
So -- is there any way to have the DSC engine only fetch a tag value when you really need it, rather than always fetching every tag in the database?
Kevin Roche
Advisory Engineer/Scientist
Spintronics and Magnetoelectronics group
IBM Research Almaden

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