hyper threading technology

[yankee]

(Fun Factoid: The percentage of time the Pentium 4 spends clearing/reinitializing the pipeline from mispredicted branches is approximately equal to the percentage of instructions which are branch instructions in the code being executed)

That can't be right! Wouldn't that mean that you've pretty much made prefetched data statistically useless (at least for branches)?

[mrugly]

I've decided to go with and have puchased,though not recieved, a
athlon xp2800-I realize this is not the latest greatest,but is certainly fast enough for me.This is also a great learning experiance for me since my fortay is as commercial electrician-I use defcon as a tool ,a very useful one and try to think first of my posts and use the search feature ,since I'm definatly afraid to get on Chris's bad side .It is humorous, however, to see him flame others :D

[bascule]

does anyone know the benifits of this;hyperthreading technology ?.Are other processors just as fast? I'm getting my shopping list together for my custom built computer.

Typically Symmetric MultiThreading (a.k.a SMT, of which HyperThreading is an implementation) is only beneficial on multicore processors. However, in the case of the Pentium 4 due to extraordinarily boneheaded design decisions (which clearly came from the marketing department to drive up clock speed, namely its TWENTY stage pipeline) ensure that the execution units of the Pentium 4 will be starved for a somewhat sizable percentage of the time.

(Fun Factoid: The percentage of time the Pentium 4 spends clearing/reinitializing the pipeline from mispredicted branches is approximately equal to the percentage of instructions which are branch instructions in the code being executed)

So, mainly, HyperThreading provides a way to utilize those starved execution units. Since this requires a separate instruction decoding pipeline, the processor becomes capable of handling two threads in hardware, which provides a nice workaround to prevent a single process from monopolizing system resources on operating systems which depend heavily on time share schedulers (i.e. Windows, Linux, FreeBSD, etc) as opposed to more intelligent schedulers such as fair share schedulers present on the higher end Unices.

I hope that answers your question.

(P.S. I would still recommend Dell. Through a recent Slickdeal you could get a Dell Dimension with a 2.53GHz P4 w\ 533MHz FSB, 256MB RAM, 80GB HDD, and 48X CD-RW drive for $380 after $50 MIR.)

[ripshy]

Google? I got a good listing by searching for "benefits" + "Hyperthreading technology"

[mrugly]

does anyone know the benifits of this;hyperthreading technology ?.Are other processors just as fast? I'm getting my shopping list together for my custom built computer.