Multithreading - What's it Mean to Developers?

sysadmn writes "Yet another reason not to count Sun out: Chip Multithreading. CMT, as Sun calls it, is the use of hardware to assist in the execution of multiple simultaneous tasks - even on a single processor. This excellent tutorial on Sun's Developer site explains the technology, and why throughput has become more important than absolute speed in the enterprise. From the intro: Chip multi-threading (CMT) brings to hardware the concept of multi-threading, similar to software multi-threading. ... A CMT-enabled processor, similar to software multi-threading, executes many software threads simultaneously within a processor on cores. So in a system with CMT processors, software threads can be executed simultaneously within one processor or across many processors. Executing software threads simultaneously within a single processor increases a processor's efficiency as wait latencies are minimized. "

Comments

I didn't RTFA but...

[cmburns69]

Can somebody explain to me how this differs from intel's hyperthreading technology?

Is this just a fancy name for sticking multiple cores on the same die?

What's the real story here?

I am not really that impressed.

[Ex Machina]

This is kind of a trivial optimization! Basically, you extend your pthreads library so all the threads within a single shared memory application schedule themselves on cores on the same chip. Big deal! Now if it could figure out how to schedule processes on "adjacent" cpus to optimize their common memory accesses, I'd be more impressed.