Phantom Duel Processors
Articles and Tips: qna
01 Feb 2003
Q.
My company's IS Department was quite excited to receive five new Dell PE2650s to run NetWare 6. After installing NetWare, I have noticed a problem. It is weird, but the server seems to think it has two processors, when it does not. The initial boot screen where the Speed rating is displayed, shows two processors, and the monitor indicates two processors. Have you seen this? I currently am seeing this on all five servers. Any and all help will be appreciated.
Dueling in Delray Beach
A.
Dear Dueling: I suspect that your new Dell servers are using hyper-threading. Quoting from Intel's Web site (http://www.intel.com), "Hyper-Threading Technology includes logic and resources that allows a single processor package to appear as two logical processors to the operating system. Processors with Hyper-Threading Technology can simultaneously execute two threads of code.
"This technology utilizes the CPU resources more efficiently, cuts down CPU idle time, and advances the Pentium 4 processor architecture to new performance levels. During program execution, sometimes an active thread has to wait for instructions to finish, to access I/O, or to access memory. CPU resources can be underutilized until the dependency is resolved. These brief waiting periods can happen frequently in certain situations, and are necessary for correct program execution.
"We designed the Pentium 4 processor supporting Hyper-Threading Technology to present two logical processors to the operating system. As a result, when one active thread stalls, another one can continue to execute and utilize CPU resources."
Windows automatically uses hyper-threading, with NetWare v5.1 and NetWare v6 supporting it via ACPIDRV.PSM. If you don't want to use hyper-threading, remove the ACPIDRV.PSM from your c:\nwserver\startup.ncf file.
* Originally published in Novell AppNotes
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