Hyperthreading

[jjohnthedon1]

Is hyperthreading software on the chip or is it something actually on the chip ?

Like split modual kinda think like the fx chips ?

[Godlygamer23]

Hyper-threading is largely software. The hardware difference between a Core i7 and Core i5(a typical desktop variant) inside the cores is double the registers. But that's it.

[jjohnthedon1]

Hyper-threading is largely software. The hardware difference between a Core i7 and Core i5(a typical desktop variant) inside the cores is double the registers. But that's it.

cheers bro

[xgn]

Windows xp and all newer versions use hyperthreading always.

[Godlygamer23]

Windows xp and all newer versions use hyperthreading always.

On certain CPUs, sure, unless it's explicitly disabled in the BIOS.

[jjohnthedon1]

Windows xp and all newer versions use hyperthreading always.

not what I asked and godly has explained what I wanted to no

[xgn]

 

 

Hyperthreading is detected as extra cores in windows and thats kind of what it does it allow you to run 2 threads instead of one.

[LukeTim]

Hyper-threading is largely software. The hardware difference between a Core i7 and Core i5(a typical desktop variant) inside the cores is double the registers. But that's it.

It's software? I understood that it was an extra instruction queue. Two threads can make use of different resources (ALU, Load/Store Unit, Floating Point Unit etc.) in the core simultaneously.

It is an implementation of Simultaneous Multithreading, and Intel is not the only chip designer/manufacturer to use it. MIPS cpus, for example, can support up to 4 threads per core.

[Godlygamer23]

It's software? I understood that it was an extra instruction queue. Two threads can make use of different resources (ALU, Load/Store Unit, Floating Point Unit etc.) in the core simultaneously.

It is an implementation of Simultaneous Multithreading, and Intel is not the only chip designer/manufacturer to use it. MIPS cpus, for example, can support up to 4 threads per core.

Yes, but it's implemented through software. The microcode tells the board if it supports hyper-threading. The process doesn't indicate the implementation. Threads are done in software.

[LukeTim]

Yes, but it's implemented through software. The microcode tells the board if it supports hyper-threading. The process doesn't indicate the implementation. Threads are done in software.

Sorry, I'm a bit confused. How is it implemented through software? Is there an on-chip microcontroller scheduling the two threads?

[Godlygamer23]

Sorry, I'm a bit confused. How is it implemented through software? Is there an on-chip microcontroller scheduling the two threads?

The Operating System has to be aware of the hyper-threading function or it doesn't work - it's not a function of the chip that's actually done by the chip. The OS has to schedule the tasks and the program must support the extra threads.

[arnavvr]

Hyper-threading is largely software. The hardware difference between a Core i7 and Core i5(a typical desktop variant) inside the cores is double the registers. But that's it.

 

So if it's largely software, you should be able to make a Core i5 a Core i7.

[Godlygamer23]

So if it's largely software, you should be able to make a Core i5 a Core i7.

I guess you could try.

[LukeTim]

The Operating System has to be aware of the hyper-threading function or it doesn't work - it's not a function of the chip that's actually done by the chip. The OS has to schedule the tasks and the program must support the extra threads.

The OS schedules tasks anyway. A hyperthreaded core tells the OS that it can schedule two tasks at once on that core and the core will be able to handle their contexts concurrently and dispatch their instructions simultaneously. In fact, on a non-hyperthreading aware OS, the core appears as two physical cores able to be scheduled on.

What do you think hyperthreading is exactly?

[Guest]

not what I asked and godly has explained what I wanted to no

I no things, I could tell you them? 

[Godlygamer23]

The OS schedules tasks anyway. A hyperthreaded core tells the OS that it can schedule two tasks at once on that core and the core will be able to handle their contexts concurrently and dispatch their instructions simultaneously. In fact, on a non-hyperthreading aware OS, the core appears as two physical cores able to be scheduled on.

What do you think hyperthreading is exactly?

From the Wikipedia article

With HTT, one physical core appears as two processors to the operating system, which can use each core to schedule two processes at once.

In addition to requiring simultaneous multithreading (SMT) support in the operating system, hyper-threading can be properly utilized only with an operating system specifically optimized for it.

Even if the OS has no support for HTT but supports SMT along with the motherboard having support for HTT, that would explain to me why a unaware OS would see the hyper-threaded cores as physical cores. The same information is being reported by the BIOS, but the OS has to interpret it somehow. Given that, Intel recommends HTT be disabled on OSes that do not support HTT.

[SteveGrabowski0]

Hyper-threading is largely software. The hardware difference between a Core i7 and Core i5(a typical desktop variant) inside the cores is double the registers. But that's it.

 

Wow, I didn't know HT chips have double the registers enabled as their non-HT versions with the same number of physical cores. Not having to store and load registers every single time the core switches the executing thread gives a straightforward explanation of why it can really help in programs with lots of parallelization.

[LukeTim]

Even if the OS has no support for HTT but supports SMT along with the motherboard having support for HTT, that would explain to me why a unaware OS would see the hyper-threaded cores as physical cores. The same information is being reported by the BIOS, but the OS has to interpret it somehow. Given that, Intel recommends HTT be disabled on OSes that do not support HTT.

But the need for software support doesn't mean you can ignore the hardware. This sounds like saying "A GPU is largely software because you need drivers for it".