Re: What is the difference between hyper-threading multi-threading and super-threadin

Hi sruti,

Multithreading, also called concurrency, is a programming language feature which allows the programmer to construct multiple independent "threads" of execution. This allows applications to be executing multiple functions simultaneously, and can be a useful programming model in many situations. For instance, you might want an application to be able to perform a complex operation such as loading a file from disk without hanging its user interface. In this case, the file-loading function could be in a separate thread from the user interface functions.

Java language has most well defined libraries that can be used for Threading and Multi Threading.

Hyper-Threading works by duplicating certain sections of the processor—those that store the architectural state—but not duplicating the main execution resources. This allows a Hyper-Threading equipped processor to pretend to be two "logical" processors to the host operating system, allowing the operating system to schedule two threads or processes simultaneously. Where execution resources in a non-Hyper-Threading capable processor are not used by the current task, and especially when the processor is stalled, a Hyper-Threading equipped processor may use those execution resources to execute another scheduled task.

Super-threading is a form of multithreading, that appeared in Pentium processors prior to the introduction of hyperthreading.In super-threading, the processor can execute instructions from a different thread each cycle. Thus cycles left unused by one thread can be used by another that is ready to run. Still, a given thread is almost surely not utilizing all the multiple execution units of a modern processor at the same time. More advanced implementations of SMT allow multiple threads to run in the same cycle, using different execution units of a superscalar processor.

With Regards,
Mitesh Manani
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