INTEL HYPER THREADING TECHNOLOGY

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Why Thread Your Application?



Increased responsiveness and worker productivity
Increased application responsiveness when different tasks run in parallel.

Improved performance in parallel environments
When running computations on multiple processors.

More computation per cubic foot of data center
Web-based apps are often multi-threaded by nature.

Performance + responsiveness makes it easier to add new features
Taking full advantage of Multi-Core hardware requires,
Multi-threaded softwares.


Multithreading


Time that processors wasted running single tasks while waiting for certain events to complete, software developers began wondering if the processor could be doing some other work at the same time.



To arrive at a solution, software architects began writing operating systems that supported running pieces of programs, called threads.

Threads are small tasks that can run independently. Each thread gets its own time slice, so each thread represents
one basic unit of processor utilization.

Threads are organized into processes, which are composed of one or more threads. All threads in a process share access to the process resources.


Hyper Threading Technology


Presents software with two logical processors even though only one physical processor is present. Effectively doubling the number of CPUs seen by the OS.

The OS is tricked into seeing two processors because a HT processor has two sets of architectural sate resources.

It is still technically only a single processor because the compute resources (execution units) are not doubled.