Tuesday, September 6th 2016

SMT and Power Management Behind "Kaby Lake" and "ZEN" Windows 10 Restrictions

Microsoft recently sparked a stir when it was reported that the company will support upcoming CPU architectures by Intel and AMD only on Windows 10, with the keyword being "support" and not "compatibility." This means that Microsoft will offer customer-support and likely serve updates to Intel "Kaby Lake" and AMD "ZEN" machines only running Windows 10 (and its enterprise variant Windows Server 2016, based on the NT 10 kernel), and not older versions of Windows. The processors themselves are compatible with any x86 operating system, Windows or *nix, 32-bit or 64-bit. HotHardware dug out the likely causes of this decision.

Apparently, new power-management and SMT features are behind the decision. With its "Kaby Lake" microarchitecture, Intel is introducing a new power-management feature called Speed Shift Technology. This lets the processor adjust its clock-speed to match processing loads at response time of 15 ms. This likely requires OS-level hooks, so the on-die power-management components can poll for processing loads and accordingly raise or lower clock-speeds 66.66 times each second, at no CPU cost. In its ZEN microarchitecture reveal, AMD too spoke about fine-grained, multi-domain clock-gating (≠ power-gating) on its "ZEN" based processors, such as "Summit Ridge."
AMD "ZEN" processors introduce simultaneous multi-threading, a feature that exposes each physical core as two logical CPUs to the OS, for better utilization of on-die resources. Intel's implementation of SMT is the HyperThreading Technology (HTT), and has been around for over a decade. AMD's SMT implementation isn't identical to that of HyperThreading, with the two threads on a CPU competing for resources in a method unique to AMD. This can't work without the OS kernel and scheduler being aware of the method. You'll remember that Microsoft had to update the kernel and scheduler of Windows 7 in a similar way, to optimize it for "Bulldozer."

These, HotHardware argues, could be the likely reasons why Microsoft is limiting support for the new CPU microarchitectures to Windows 10. Source: HotHardware
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57 Comments on SMT and Power Management Behind "Kaby Lake" and "ZEN" Windows 10 Restrictions

#51
EarthDog
That's only supposed to be, legally, for people who use assistive tech.. that said, I agree with the rest of your post. :)
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#52
Frick
Fishfaced Nincompoop
Caring1
It's kind of silly not to support the most popular O.S. (W7) to make it faster and more secure, especially when people already bought it and like it.
They are making it more secure though. That's the purpose of the "extended support" phase.
Posted on Reply
#53
midnightoil
Microsoft can try to scare people on to Windows 10 all they want, but a lot will never move. 7 is the end of the line as far as Windows is concerned, for me, as it is with many individuals and businesses. Loss of control, lack of security and foisting of tablet like UI and Windows Store are too much.

This is purely a scare tactic anyway. Intel have sometimes toed the 'Wintel' line before, aligning with MS, but I doubt they do here, and AMD certainly won't.

There's a roughly 0% chance of AMD not writing drivers for W7 and W8(.1) for Zen. They want to sell chips and regain market share. They're not concerned with MS' shenanigans.

I'd say there's less than 20% chance of Intel not releasing them, because if they don't, then they lose all those sales W7 and W8.1 sales to AMD.

Indeed, MS will most likely climb down quickly themselves when the time comes, when large companies tell them they'll be moving to 'nix.
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#54
cdawall
where the hell are my stars
midnightoil
Microsoft can try to scare people on to Windows 10 all they want, but a lot will never move. 7 is the end of the line as far as Windows is concerned, for me, as it is with many individuals and businesses. Loss of control, lack of security and foisting of tablet like UI and Windows Store are too much.

This is purely a scare tactic anyway. Intel have sometimes toed the 'Wintel' line before, aligning with MS, but I doubt they do here, and AMD certainly won't.

There's a roughly 0% chance of AMD not writing drivers for W7 and W8(.1) for Zen. They want to sell chips and regain market share. They're not concerned with MS' shenanigans.

I'd say there's less than 20% chance of Intel not releasing them, because if they don't, then they lose all those sales W7 and W8.1 sales to AMD.

Indeed, MS will most likely climb down quickly themselves when the time comes, when large companies tell them they'll be moving to 'nix.
So what do you think companies will just never upgrade past 7? Fucking lagards. Guess what they will upgrade to 10 it will just take time, just like the upgrade to 7 from XP.
Posted on Reply
#55
Easo
midnightoil
Microsoft can try to scare people on to Windows 10 all they want, but a lot will never move. 7 is the end of the line as far as Windows is concerned, for me, as it is with many individuals and businesses. Loss of control, lack of security and foisting of tablet like UI and Windows Store are too much.

This is purely a scare tactic anyway. Intel have sometimes toed the 'Wintel' line before, aligning with MS, but I doubt they do here, and AMD certainly won't.

There's a roughly 0% chance of AMD not writing drivers for W7 and W8(.1) for Zen. They want to sell chips and regain market share. They're not concerned with MS' shenanigans.

I'd say there's less than 20% chance of Intel not releasing them, because if they don't, then they lose all those sales W7 and W8.1 sales to AMD.

Indeed, MS will most likely climb down quickly themselves when the time comes, when large companies tell them they'll be moving to 'nix.
Intel and AMD both officially have said that they will support only Win10 on Kaby Lake/ZEN.
Large companies have started moving to Win10, or at least have pilots running. Trust me, there won't be mass exodus to Linux.
Posted on Reply
#56
Audiophizile
Easo
Intel and AMD both officially have said that they will support only Win10 on Kaby Lake/ZEN.
Large companies have started moving to Win10, or at least have pilots running. Trust me, there won't be mass exodus to Linux.
Yep. Working for an msp that supports over 100 small to medium size businesses quite a few have upgraded to 10. If they have legacy software that will only support 7 they leave the machines that need it on 7. Most currently produced and supported software will run on 10 and if it doesn't right now it will soon. Not a ton of reasons to not upgrade.
Posted on Reply
#57
ZeDestructor
bug
RHEL gets 7-10 years of support (depends how old you go). But that's an enterprise product and even that doesn't get support for newer CPU architectures. I think RHEL5 is stuck somewhere at Haswell.
So does MS. 5 years mainstream + 5 years extended support.

RHEL on the other hand has a 7-10 year support length, with shorter intermediary phases that you are supposed to intermediately upgrade to (very Windows 10-like actually). On those versions, you also skip a lot of feature upgrades, and in order for their support cycle to work at all, RH (and others) spend a lot of time and money backporting stuff from newer bits.

midnightoil
Microsoft can try to scare people on to Windows 10 all they want, but a lot will never move. 7 is the end of the line as far as Windows is concerned, for me, as it is with many individuals and businesses. Loss of control, lack of security and foisting of tablet like UI and Windows Store are too much.

This is purely a scare tactic anyway. Intel have sometimes toed the 'Wintel' line before, aligning with MS, but I doubt they do here, and AMD certainly won't.

There's a roughly 0% chance of AMD not writing drivers for W7 and W8(.1) for Zen. They want to sell chips and regain market share. They're not concerned with MS' shenanigans.

I'd say there's less than 20% chance of Intel not releasing them, because if they don't, then they lose all those sales W7 and W8.1 sales to AMD.

Indeed, MS will most likely climb down quickly themselves when the time comes, when large companies tell them they'll be moving to 'nix.
I've heard this batch of arguments around 2006-2009 when people were clinging to their XP machines like limpets. I've heard the same around the early 2000s when XP launched and people clung to their 98SE machines just as hard. Happens every cycle, and every time they suck it up eventually or move away from Windows.

For a lot of companies, moving away from Windows isn't really much of an option. Between Windows-only software (Active Directory, MSOffice, Exchange for example), support contracts (commercial support for RHEL or Debian ain't free... and if you don't have a support contract, you almost always need to hire in-house talent to do it for you), the cost of porting stuff/migrating to new equivalent solutions, training employees and other things I've probably forgotten, it just doesn't make sense.
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