Product Documentation

Database Administrator's Guide

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CPUs and Threads

With years of experience developing multi-threaded applications, FairCom has built multi-threading into all FairCom DB Servers since the late 1980s. This allows FairCom DB Server to take advantage of any processors or threads available to it.

Simultaneous multithreading (SMT) is a technique some processor manufacturers use so that a single processor can execute multiple threads. Intel’s hyper-threading technology is an implementation of SMT that supports two threads on each processor core.

Physical chip with 4 cores, each with 2 threads

A single CPU chip (1 “socket”) with 4 cores and 8 threads

In the limiting case, SMT would be as effective as multiple processors or CPUs; in actual practice the performance gains depend on the application. In particular, applications that are I/O bound, such as databases that must wait for disks, can benefit from SMT because one thread can execute while another is waiting for I/O.

Modern processor design allows multiple processor cores to be packaged in one integrated circuit chip. Each of those cores is essentially a complete CPU. For example, a single chip may contain four processor cores, so it is equivalent to four separate CPUs. In addition, each core may use SMT, causing it to appear to be two or more processors. The result is a single chip could contain four cores each of which appears as two processors, for a total of eight processors reported by the operating system. A large server could use more than one of these chips, resulting in a large number of reported processors.

The amount of performance improvement provided by these technologies depends on the specifics of your application.

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