"Hyper-threading" and Windows 2000 1

[MattK]

Hi all,

We recently purchased a new server, which came with a P4 Xeon 2.4Ghz with Intel's 'Hyper-Threading' technology. Hyper-threading makes the one physical CPU appear as two 'logical' CPUs in BIOS, and hence to take advantage of it, Windows 2000 needs to have a multi-processor HAL installed.

When I was doing the initial install on the server, I did not realise this, so I installed it with a single-processor HAL. All works fine, but now I have realised my mistake and want to let it use both 'logical' CPUs, and hence I need to put W2K into multi-CPU mode. I followed the instructions available on the internet of going into Device Manager -> Computer, and changing the druiver for the existing entry (MPS Uniprocessor PC) to multiprocessor (MPS Multiprocessor PC), but upon rebooting, Windows 2000 is still only seeing one processor (only one graph in Ctrl-Alt-Del->Performance, only one processor reported in Computer Management, etc).

Does anyone know what's wrong, or if I have missed a step? The processor definately supports HT, and the computer's bios reports 'two' processors, Windows 2000 just refuses too.

Cheers,
Matt

 

[JackyZhang]

Windows 2000 doesn't support Intel Hyper-threading technology.
In market, only Windows Xp and Windows .Net support Hyper-threading technology.
Even Linux doesn't support this kind of technology right now.

 

[MattK]

I was under the impression that while Windows 2000 doesn't 'natively' understand HT, it can take advantage of it because it simply believes there are two processors in the system. Are you sure it's not possible to use it like this because I'm sure I've talked to people before who have used HT and W2K.

Thanks for the reply though,
Matt

 

[neilcresswell]

Windows 2000 DOES see a single processor as two if the machine is equipped with Hyper Threading. You need to install the latest service pack, and also ensure that HyperThreading is enabled in the BIOS.
What is the Server type and Manufacturer. The IBM servers for example have their own HAL that understands hyperthreading and they only see the number of procs physically installed.

N

 

[MattK]

Thanks for the reply Neil.

Firstly, HT is definately enabled in bios. I have the latest service pack installed - do I perhaps need to re-install it after setting the computer to the multiprocessor HAL?

The server is a no-name-brand (sort of). It's built up around an Intel server chassis and server-grade motherboard, but it's not an 'off-the-shelf' Intel box.

 

[Galrahn]

I would think you do need to install a multiprocessor HAL in order for it to work. We recently purchased the new DELL 6650s with 4 P4 Xeons, and chose to use Advanced Server so we can take advantage of the hyperthreading (get the 8 processors). Afterall, natice support is not there in 2K, and to use the extra horsepower we had to use Adv. Server to get past the 2K processor license issue.

Hyperthreading does work in 2K though, because we have it configured and 2K is treating everything like we have 8 processors installed, even though there are only 4 physical processors.

Galrahn
galrahn@galrahn.com

 

[JackyZhang]

Please check this link to Intel

http://www.intel.com/support/platform/ht/os.htm

Hyper-Threading Technology†
Operating Systems that Include Optimizations for Hyper-Threading Technology

Microsoft* Windows* Operating System Based PCs
The following desktop operating systems include optimizations for HT Technology and are currently eligible to carry the new Intel® Pentium® 4 Processor with HT Technology† logo:

Microsoft* Windows* XP Professional Edition
Microsoft* Windows* XP Home Edition

The following operating systems are not recommended for use with Hyper-Threading Technology. If you are using one of the following operating systems, it is advised that you should disable Hyper-Threading Technology in the system BIOS Setup program:

Microsoft Windows 2000 (all versions)
Microsoft Windows NT* 4.0
Microsoft Windows Me
Microsoft Windows 98
Microsoft Windows 98 SE

Linux* Operating System Based PCs
Intel is working with the Linux community to get necessary optimizations for HT Technology included in distributions. Note that while Linux operating system based PCs may have HT Technology enabled, only PCs based on Microsoft* Windows* XP Professional Edition or Microsoft* Windows* Home Edition are currently eligible to carry the new Intel Pentium 4 Processor with HT Technology logo. If purchasing a Linux OS-based PC, check with your PC vendor to determine if the PC includes the necessary system ingredients for HT Technology and has HT Technology enabled.

 

[Galrahn]

JackyZhang is right, but Microsoft also has an opinion.

"All versions of the Windows 2000 operating system are fully compliant with HT and should run without error on HT-enabled systems. However, neither Windows 2000 nor any of its service packs support the identification of HT processors. The type of modifications that are required for HT processor identification and support are not typically supported in a service pack. There are no plans to introduce this support in any future Windows 2000 service pack.

As a result, Windows 2000 treats each logical processor as if it were an individual physical processor. The operating system attempts to start each logical processor in the sequence in which it was listed by the BIOS until the number of processors that have been started is equal to the processor license limit for that version of the operating system."

A more complete document regarding Hyper-Threading Technology (HT) in Windows can be found at

http://www.microsoft.com/hwdev/platform/proc/HT-Windows.asp

The file you download there has more detail regarding HT Technology on Windows 2000 in Section 4.1 of the document. It is that document in fact that helped us decide to go ahead and use the HT Technology with our DELL 6550's with Windows 2000 Advanced Server.

Galrahn
galrahn@galrahn.com