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This doesn't seem correct? "Windows 11 boosts performance of big.little x86 CPUs shows testing" https://www.neowin.net/news/windows-11-boosts-performance-of-b

This doesn't seem correct? "Windows 11 boosts performance of big.little x86 CPUs shows testing" https://www.neowin.net/news/windows-11-boosts-performance-of-biglittle-x86-cpus-shows-testing/ https://www.neowin.net/news/windows-11-boosts-performance-of... "Microsoft and Intel confirm Windows 11 is optimized for Big.Little design" https://www.neowin.net/news/microsoft-and-intel-confirm-windows-11-is-optimized-for-alder-lakes-biglittle-design/ https://www.neowin.net/news/microsoft-and-intel-confirm-wind...

Dalewyn 3y ago
Windows 11 knows how to use Intel performance and efficiency cores thanks to Intel providing Intel Thread Director which gives some hints to Windows 11's scheduler. AMD, from what I can tell, doesn't provide an equivalent to Intel Thread Director so Windows 11's scheduler has to work blind not unlike Windows 10's scheduler when working with Intel performance and efficiency cores. So all else being equal, it's reasonable to assume Windows 11 will not take full advantage of AMD's performance and efficiency core architecture because the scheduler is working blind.
- The_Colonel 3y ago
  > AMD, from what I can tell, doesn't provide an equivalent to Intel Thread Director Isn't that simply because AMD so far didn't have any heterogenous cores and they will quite possibly/likely work with Windows to add support for them (just like Intel did)? It might take some time, but it seems needlessly pessimistic to expect that this won't happen in some form.
  - Sakos 3y ago
    But why should it be on AMD? This needs to be a part of the OS as it is like in Linux, or as a user you're penalized for picking the company with less solid connections to Microsoft and less budget available to do something like Intel's thread director (which is how Intel's mixed cores are "supported" by Windows). Windows doesn't have any native support for heterogenous cores. It just takes the CPU's advice on what to do. That seems crazy to me.
    - The_Colonel 3y ago
      Well, who adds support for this into the Linux kernel? It's also the CPU vendors. While there is certainly a need for some common scheduler logic, there also needs to be per-vendor or even per-model support added, since the OS first needs to even figure out which cores are which and each vendor's efficiency cores have different characteristics.
      - Sakos 3y ago
        AMD can't do that for Windows. Why do they have to add a hardware component to their CPU's to do it like Intel can afford to? > Intel’s Thread Director controller puts an embedded microcontroller inside the processor such that it can monitor what each thread is doing and what it needs out of its performance metrics. Linux literally has native support for heterogenous cores that works for both AMD and Intel. There's a world of difference between contributing to the kernel to ensure their CPU's work well and AMD being forced to put a microcontroller in their CPU and develop their own CPU-internal scheduling system.
        Dalewyn 3y ago
        I think we're well past the point AMD is the "small indie dev" to "big corpo house" Intel. If AMD refuses to do what is necessary to fully bring out the performance of their hardware, that's not on Microsoft. I see Intel Thread Director quite similarly to how hardware manufacturers provide their own drivers. Sure, Microsoft could provide some generic driver, but that's not going to make full use of that hardware because only the manufacturer fully knows what's going on.
    - rewmie 3y ago
      > But why should it be on AMD? It's in the best interests of OS vendors to get processors to work. It's in the best interests of CPU vendors to get processors to work optimally on major platforms. AMD's business is selling processors. Customers buy them if they perform better than the competitor's offers at the same price range. If your competitors optimizes implementations but you drop the ball and go with unoptimized ones, it matters nothing if your product performs better in theory if customers don't see that in the real world.
  - pedrocr 3y ago
    AMD has had heterogeneous cores since at least the beginning of the year with the 7900X3D and 7950X3D. The differences between cores there are even bigger than with these parts. Some cores clock lower but have more cache than others so depending on workload the optimal cores are different. With Zen4 vs Zen4c apparently only the clocks change so some cores are strictly better than the others.
    - The_Colonel 3y ago
      Yes, that's true, AMD actually had such models since the 5X00 series. As I understand these models are somewhat niche and focused on the gaming market where AMD has some custom support for selecting the 3D cache cores. Having said that, I don't really want to defend MS, they should add full support for this, but basically I believe it's just a matter of time.
      - pedrocr 3y ago
        The 5800X3D had all cores with extra cache just like the 7800X3D. They didn't do a 5900X3D or 5950X3D so the problem didn't exist before.
Sakos 3y ago
Windows 11's "support" is more of a lazy hack. It doesn't work without the CPU literally telling it how to schedule threads across its cores: https://www.anandtech.com/show/16881/a-deep-dive-into-intels-alder-lake-microarchitectures/2 https://www.anandtech.com/show/16881/a-deep-dive-into-intels...

Dalewyn 3y ago

Windows 11 knows how to use Intel performance and efficiency cores thanks to Intel providing Intel Thread Director which gives some hints to Windows 11's scheduler. AMD, from what I can tell, doesn't provide an equivalent to Intel Thread Director so Windows 11's scheduler has to work blind not unlike Windows 10's scheduler when working with Intel performance and efficiency cores. So all else being equal, it's reasonable to assume Windows 11 will not take full advantage of AMD's performance and efficiency core architecture because the scheduler is working blind.

The_Colonel 3y ago
> AMD, from what I can tell, doesn't provide an equivalent to Intel Thread Director Isn't that simply because AMD so far didn't have any heterogenous cores and they will quite possibly/likely work with Windows to add support for them (just like Intel did)? It might take some time, but it seems needlessly pessimistic to expect that this won't happen in some form.
- Sakos 3y ago
  But why should it be on AMD? This needs to be a part of the OS as it is like in Linux, or as a user you're penalized for picking the company with less solid connections to Microsoft and less budget available to do something like Intel's thread director (which is how Intel's mixed cores are "supported" by Windows). Windows doesn't have any native support for heterogenous cores. It just takes the CPU's advice on what to do. That seems crazy to me.
  - The_Colonel 3y ago
    Well, who adds support for this into the Linux kernel? It's also the CPU vendors. While there is certainly a need for some common scheduler logic, there also needs to be per-vendor or even per-model support added, since the OS first needs to even figure out which cores are which and each vendor's efficiency cores have different characteristics.
    - Sakos 3y ago
      AMD can't do that for Windows. Why do they have to add a hardware component to their CPU's to do it like Intel can afford to? > Intel’s Thread Director controller puts an embedded microcontroller inside the processor such that it can monitor what each thread is doing and what it needs out of its performance metrics. Linux literally has native support for heterogenous cores that works for both AMD and Intel. There's a world of difference between contributing to the kernel to ensure their CPU's work well and AMD being forced to put a microcontroller in their CPU and develop their own CPU-internal scheduling system.
      - Dalewyn 3y ago
        I think we're well past the point AMD is the "small indie dev" to "big corpo house" Intel. If AMD refuses to do what is necessary to fully bring out the performance of their hardware, that's not on Microsoft. I see Intel Thread Director quite similarly to how hardware manufacturers provide their own drivers. Sure, Microsoft could provide some generic driver, but that's not going to make full use of that hardware because only the manufacturer fully knows what's going on.
  - rewmie 3y ago
    > But why should it be on AMD? It's in the best interests of OS vendors to get processors to work. It's in the best interests of CPU vendors to get processors to work optimally on major platforms. AMD's business is selling processors. Customers buy them if they perform better than the competitor's offers at the same price range. If your competitors optimizes implementations but you drop the ball and go with unoptimized ones, it matters nothing if your product performs better in theory if customers don't see that in the real world.
- pedrocr 3y ago
  AMD has had heterogeneous cores since at least the beginning of the year with the 7900X3D and 7950X3D. The differences between cores there are even bigger than with these parts. Some cores clock lower but have more cache than others so depending on workload the optimal cores are different. With Zen4 vs Zen4c apparently only the clocks change so some cores are strictly better than the others.
  - The_Colonel 3y ago
    Yes, that's true, AMD actually had such models since the 5X00 series. As I understand these models are somewhat niche and focused on the gaming market where AMD has some custom support for selecting the 3D cache cores. Having said that, I don't really want to defend MS, they should add full support for this, but basically I believe it's just a matter of time.
    - pedrocr 3y ago
      The 5800X3D had all cores with extra cache just like the 7800X3D. They didn't do a 5900X3D or 5950X3D so the problem didn't exist before.

Sakos 3y ago

Windows 11's "support" is more of a lazy hack. It doesn't work without the CPU literally telling it how to schedule threads across its cores: https://www.anandtech.com/show/16881/a-deep-dive-into-intels-alder-lake-microarchitectures/2 https://www.anandtech.com/show/16881/a-deep-dive-into-intels...