HyperThreading

From Computing Knowledgebase

HyperThreading, abbreviated HTT, short for HyperThreading Technology, is a method that allows Two hardware Threads to run on a single CPU. It essentually fools the Operating System into thinking the System has double the number of Physical Processors installed. So, if a System has one Physical Processor, with HyperThreading enabled, the System will see Two Logical Processors. HTT is also referred to as SMT, or Simultaneous MultiThreading

Portions of the SSE3 SIMD Extensions relate to Memory and Thread management.

HyperThreading was first enabled on Intel's Xeon line of Processors, before it was migrated to Intel's Pentium 4 Platform

HyperThreading has, however, been shown to have a Critical Flaw in the way one Thread can monitor another. In most instances, the Cache is partitioned to allow multiple threads to occupy different portions of it (So, a 1MB L2 Cache, can be partitioned into two 512KB Blocks). However, one Thread can Monitor another in the same Cache Space. This can lead to the theft of Cryptographic Keys, and password details.