From mboxrd@z Thu Jan  1 00:00:00 1970
To: 9fans@cse.psu.edu
From: Vasile Rotaru <vrotaru@seznam.cz>
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References: <e22617b7b2cd8262db779d45e48c9648@plan9.bell-labs.com>, <Pine.LNX.4.44.0312280911230.31428-100000@maxroach.lanl.gov>
Subject: Re: [9fans] hyperthreading
Date: Mon,  5 Jan 2004 11:03:34 +0000
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On Sun, 28 Dec 2003 17:12:48 +0100, ron minnich wrote:

> hyperthreading: don't waste your time.
>=20
> hype-r-threading.
>=20
> ron

Let's say if I understand it correctly.

I take a very simple example, say we need to fill a big array.

 case a: Single processor, single thread
   (the base case)

 case b: Single processor, two threads.
    (one fills the even, the other the odd positions).
     Slower, time lost in task switch.

 case c: Single HP processor two threads.
     A litle faster than in case b), since less time lost in task switch.

 case d) Two processors, two threads.
     Solid speed gain, almost two times faster.

 So I just can't think of a realistic scenario, where the speed of task
switching will be noticeable..

bas