What is a CPU Thread?

[Zhanlun Liang]

A CPU has cores and thread, but what is a thread??

 

Thanks ! ! !

[Bloodyvalley]

If it's an i7, every physical core makes one thread, which is a logical core, or a virtual core if you will.

[KemoKa]

A thread is more the execution by a CPU of a task, rather than the task itself, if I understand the technology correctly. Each core in a CPU can normally do a single thread. If it is hyperthreaded (an i3 or an i7) then it has specialized scheduling processors that allow it to utilize all of the core's ability to process instructions in a single tick, instead of wasting valuable nanoseconds doing nothing. And it's not just a gimmick, either, it works surprisingly well in some use cases.

[LIGISTX]

Think of it like cars going through tunnels. A "core" or an "actual logical thread" is a tunnel, where a virtual core or virtual thread is a lane before the tunnel.

 

So, a single core without HT *this means this cpu only has 1 core and 1 thread* has a single lane going to a single tunnel, the CPU can only process one lane of cars *data* at a time.

 

Now lets jump to a Pentium 4 with HT, the tunnel has two lanes leading up to it, but still only 1 tunnel. So cars from each lane can switch back and forth taking turns going through the tunnel, thus processing more stuff from two different applications at once, but still only with one tunnel.

 

Now a dual core without HT is 2 lanes, and 2 tunnels.

 

A current i7 has 8 lanes going to 4 tunnels.

 

A very general explanation, but that basically is how that works