Re: To thread or not to thread ?

From:
Pete Becker <pete@versatilecoding.com>
Newsgroups:
comp.lang.c++.moderated
Date:
10 Jan 2007 21:39:58 -0500
Message-ID:
<UqudnbjTOvkVwzjYnZ2dnUVZ_ujinZ2d@giganews.com>
Carlos Moreno wrote:

JohnQ wrote:

Why have more threads than the number of processor cores?


I'm baffled by this question ...

The above question is exactly equivalent to "why would we want
multithreading?"


Not quite. There are two different perspectives on multi-threaded
programming. On is "distribute the workload optimally among the
available processors." That's when you want just as many threads as
processor cores. The other is "logically divide the process into tasks
that can be run concurrently." That's when you want as many threads as
appropriate, and are willing to put up with some thrashing and delays
when you have more threads than cores.

--

    -- Pete
Roundhouse Consulting, Ltd. (www.versatilecoding.com)
Author of "The Standard C++ Library Extensions: a Tutorial and
Reference." (www.petebecker.com/tr1book)

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