Intel Dual Core - How do they work?

[joker_927]

Does anyone have an article that explains how two seperate proccessors (specifically the Intel Core 2 Duo) communicate with each other? I know they have a shared cache but beyond that it seems as though the two cores never communicate.

It's my belief that the OS chooses a core to execute a thread (if more than 1 thread exists) and then the core executes the instruction without ever "communicating" with the other core. Is this correct?

[jamhough22]

I would of thought that the 2 cores would act as one core so the os doesent have to choose......just a guess....
but yours sound right aswell...

[zulquar]

I THINK THEY COMMUNICATE VIA THE INTERNAL BUS SINCE THERE ON THE SAME DIE UNLIKE THE PENTIUM D

[joker_927]

Wow, worst responces ever.

[KarmaKiller]

Hi there.
Your asking kind of a broad question, as Core 2 chips have different cores. Some use Conroe's, other's use Allendales. Some of the Quads use Kentsfield cores, and others use Yorkfield, etc.
Check out the wiki, and then come back and ask some questions.
http://en.wikipedia.org/wiki/Intel_Core_2#Conroe

But in general, this link will explain how they work.
http://en.wikipedia.org/wiki/Intel_C...roarchitecture

[EXreaction]

Processors do not work like that. They are given instructions and calculate the answer. They can access the cache memory used by the other core if the cache is shared.

[carl33p]

A pretty difficult question. Proly cant be answered simply since there are so many techniques used in modern day processors. Im also note sure on what level you are wanting information, at the high-level programming stage or the lower end.

I only have an understanding of a basic MIPS processor, so Im just going to take some shots in the dark.
The actual cores do not need to communicate with each other. They simply execute the instructions which are fed to them individually. For the applications that do utilize more than a single core, isolated subsystems are assigned to each indivual core.

It's my belief that the OS chooses a core to execute a thread (if more than 1 thread exists)

I think that your assumption about the operating system choosing the cores is close to correct and would refer to multithreading, but it can also happen at the hardware level.

then the core executes the instruction without ever "communicating" with the other core.

There wouldnt be a reason for the cores to communicate with each other within a single instruction. The clock rate would become significantly slower if data had to be transfered back and forth across cores.


Ive tried researching the subject some, but it becomes very complicated. The subject tangents off into hardware, operating systems, programming, etc. But it seems right to assume that L2 cache plays the biggest role in the interconnect between the two cores.

[EXreaction]

So, basically the same thing I said, but longer?

[zulquar]

the core 2 chips have better ipc (instructions per cycle) 4 compared to that of the intel pentium d s 2 intsruction per cycle I think thats the biggest advantage the core 2 ghips have (better and mre efficient architecture )
i heard in 1 website tha athlon chips ccan communicate via internal bus due to hyper tansport and the fact that they r on the same die or sometin , maybe im wrong cant remember , but anyway6 this thread has made me understand dual cores better

[EXreaction]

Even if 2 processors could communicate, there would be no need for it. A processor isn't much different from a calculator, you tell it numbers and have it give you an answer. There is absolutely no need for them to communicate, even if they could, they just follow instructions.

If you've never looked at a list of an instruction set,
http://en.wikipedia.org/wiki/X86_instruction_listings