linux-kernel - Re: nice and hyperthreading on atom

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Message-ID: <20080906094248.5930911a@infradead.org>
Date:	Sat, 6 Sep 2008 09:42:48 -0700
From:	Arjan van de Ven <arjan@...radead.org>
To:	"Phil Endecott" <phil_wueww_endecott@...zphil.org>
Cc:	"Linux Kernel Mailing List" <linux-kernel@...r.kernel.org>
Subject: Re: nice and hyperthreading on atom

On Sat, 06 Sep 2008 16:43:31 +0100
"Phil Endecott" <phil_wueww_endecott@...zphil.org> wrote:

> Dear Experts,
> 
> I have an ASUS Eee with an Atom processor, which has hyperthreading 
> enabled.  If I have two processes, one nice and the other normal,
> they each get 50% of the CPU time.  Of course this is what you'd
> expect if the scheduler didn't understand that the two virtual
> processors are not really independent.  I'd like to fix it.
> 

but you cannot imfluence the cpu's scheduling of the instructions.

As an OS one COULD decide to just not schedule the nice task at all,
but then, especially on atom where HT has a high efficiency, your cpu
is mostly idle ...

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