[Question] - Dual Core and licencing

[jcarle]

Explain this to me then: http://www.microsoft.com/licensing/highlights/multicore.mspx

DIRECTLY FROM THAT PAGE:

Q. How does this licensing policy affect products such as Microsoft Windows XP Professional?

A. Microsoft Windows XP Professional and Microsoft Windows XP Home are not affected by this policy as they are licensed per installation and not per processor. Windows XP Professional can support up to two processors regardless of the number of cores on the processor. Microsoft Windows XP Home supports one processor.

Read what I mentioned previously, because I distinctly remember specifying that Home does not support multiple processors, but does acknowledge multiple logical processors(otherwise known as cores).

Again. Windows XP Home does NOT support symmetric multiprocessing (SMP). Windows XP Home WILL IGNORE anything other then the FIRST CORE of the FIRST PHYSICAL PROCESSOR.

Actually, for professional software, the only software limitations ARE licensing limitations.

Again! Refer to above! Microsoft Windows XP Professional and Microsoft Windows XP Home are not affected by this policy as they are licensed per installation and not per processor. Therefore, if the LICENSE permits an unlimited use of processors and cores, what stops Windows XP Home from running more then one core? The kernel. What stops Windows XP Professional from executing on more then 2 physical processors regardless of the number of cores? The kernel. So what stops XP from running 4 processors? Oh guess what? Not the licensing, THE SOFTWARE DOES.

I'm going to need some low level(not just task manager) proof on this one, because from what I've read, XP's HAL does not have any core logic as far as distributing its processes or any other processes, for that matter, across any more processors(physical or logical) than physical processor 0.

That's easy. Open up ANY multi-core/multi-processor based Windows XP Professional machine and explain to me why the second core is NEVER at 0% when system processors are above 0%?

[gdogg]

ok no use aguing back and forth with "Microsoft papers"

I did the testing

xp home does load balencing by default

works on dual cores by default ( no changin HAL needed)

xp home also, is licenced for this

and all SMP programs work just fine in xp home.

@teqguy

"Gdogg, I just explained what is actually going on within Windows and why one would go with the licensing of Professional vs Home.... and yet you went and said exactly the opposite of what I said... without giving any reason as to why your reasoning is true.

It's virtually IMPOSSIBLE for your processor to be devoting 50% of each core's resources to one task, because load balancing does not divide the process in half... it just sets the core or thread affinity to one processor, and then sets the affinity of any other processes to the other processor."

since you are extremly confused about dual core, xp home and how it all actually works. Unlike what is written on paper.

I suggest you get yourself a dual core processor.

Edited February 9, 2006 by gdogg

[nmX.Memnoch]

XP Home can make use of the second core. Period.

http://hardocp.com/article.html?art=ODcxLDE=

That's a link to a system review on HardOCP. The system was an Athlon64 X2 with XP Home installed. On page 5 of the article they stated they had problems loading one of the games until they set the CPU affinity to CPU 0 (disabling SMP/SMT for that game). This is also clearly shown in the Task Manager screenshots on the same page.

If XP Home wouldn't/couldn't use the second core it wouldn't show up in Device Manager or Task Manager, it would be completely ignored by the OS as if it wasn't even in the system. A dual-core P4EE will show up as four CPUs in XP Home because it is a single socket, dual-cored CPU with Hyperthreading.

http://www.computing.net/cpus/wwwboard/forum/12476.html

http://forums.anandtech.com/messageview.as...6&enterthread=y

Also see page 3 of this document from MS.

http://download.microsoft.com/download/f/1...hread_brief.doc

Edited February 9, 2006 by nmX.Memnoch

[jcarle]

This is what I found according to Microsoft directly:

Question:

Does Windows XP support Hyper-Threading so that my Home Edition will have two processors and my Professional Edition will have four?

Answer:

Yes, Windows XP Home Edition and Professional Edition both support Hyper-Threading technologies. The licensing for processors in Windows XP is done by counting the number of "physical" processors (via the CPUID) and not the number of "logical" (see links below for additional information on "physical" vs. "logical" processors). This means that a dual processor Home Edition computer is possible when running a Hyper-Threading enabled processor. Extended to Windows XP Professional, a system could have two physical Hyper-Threaded enabled processors and the Task Manager and System Monitor would show the computer as having four available processors. One thing to note is that when using the "numproc=" switch in the boot.ini, it is not possible to fractionalize a physical processor. For example, if a numproc=3 is put into a boot.ini on a Windows XP Professional Edition computer that shows four logical CPU's, you will not see three processors after a reboot. You will instead see only two.

The normal caveats with multi-processor computers apply. Software that isn't specifically designed to take advantage of multiple processors probably will not use the additional functionality. However, the Operating System will use Symmetric Multiprocessing (SMP) and utilize the additional logical processors to accomplish its work.

Windows XP Home Edition

Maximum Physical Processor Limit: 1

Maximum Logical Processor Limit: 2

Windows XP Professional

Maximum Physical Processor Limit: 2

Maximum Logical Processor Limit: 4

Source: https://members.microsoft.com/oemconnect/ch.../200209-10.mspx

[nmX.Memnoch]

That article is from 2002 and addresses Hyperthreading, not dual core.

XP Home will treat a single dual-core processor the same way it treats a single hyperthreaded processor. Microsoft originally stated it would not but they changed this stance even before dual-core CPUs hit the market.

I do, however, agree with you that teqguy has very little idea what he's talking about. He knows enough to sound like he's talking a good game...but half of it is misinformation.

Windows NT based operating systems ever since NT 3.1 CAN dictate which processor a thread runs on (aka process affinity). See the screenshots on page 5 of the article I linked above. If you leave the affinity at it's default, which is to use all CPUs, the kernel will put the thread on the next idle CPU. Also, it CAN divide a process up across two CPUs/cores because a single process can spawn multiple threads. It's the threads that are being "load balanced" and not the process itself.

As for the explenation of this MS page, they are talking about applications such as SQL server that are or can be licensed on a per processor basis. The page itself explains jcarle's explenation that Windows XP is licensed on a per installation basis instead of per processor. Unfortunately it appears they didn't complete the XP Home part of the answer.

Q. How does this licensing policy affect products such as Microsoft Windows XP Professional?

A. Microsoft Windows XP Professional and Microsoft Windows XP Home are not affected by this policy as they are licensed per installation and not per processor. Windows XP Professional can support up to two processors regardless of the number of cores on the processor. Microsoft Windows XP Home supports one processor.

I've also seen it mentioned elsewhere (not necessarily in this thread) that Windows XP doesn't know the difference between physical and virtual processors. This is also incorrect. Windows versions prior to Windows XP don't understand the difference, but versions from Windows XP on do.

[Innocent Devil]

slithtly off-topic:

Multi threaded and Multi Cored processors are seen as LOGICAL processors each (each core /thread)

then what makes the diff b/w P4HT,P4EE,Core Duo,AMD X2 and and a Dual Xeon,Itanium2

Adv. 4 Dual Xeon Vs X2or P4HT ??

[gdogg]

vmware dual core works too in xp home ...

[jcarle]

I do, however, agree with you that teqguy has very little idea what he's talking about. He knows enough to sound like he's talking a good game...but half of it is misinformation.

Let's stop the propaganda! B)