What is a CPU thread and how is it related to logical threads in code?

Question

I have been seeing in the literature for some of the newer CPU\'s such as the Intel Xeon \"Nehalem-EX\" as having 8 cores and 16 threads. What are they talking about here? I

Answer 1

It isn't hyper-threading renamed - it is hyper-threading (it is written on this webpage you gave link to).

Simply, processor tells OS that it has 16 cores, so it can balance tasks on doubled number of cores. Hyper-threading technology give some benefit becouse in some cases two different instructions from two different programs/threads can be executed on one core simultaneously. But for sure it will not give 200% speed up. I didn't work on such processor, but I think you can get about 10%-20% additional cpu time.