linux-kernel - Re: (ondemand) CPU governor regression between 2.6.23 and 2.6.24

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Date:	Sun, 27 Jan 2008 22:14:47 +0100
From:	Toralf Förster <toralf.foerster@....de>
To:	Mike Galbraith <efault@....de>
Cc:	Sam Ravnborg <sam@...nborg.org>, Ingo Molnar <mingo@...e.hu>,
	Peter Zijlstra <peterz@...radead.org>,
	linux-kernel@...r.kernel.org
Subject: Re: (ondemand) CPU governor  regression between 2.6.23 and 2.6.24

At Sunday 27 January 2008 Mike Galbraith wrote :
> 
> On Sun, 2008-01-27 at 13:39 +0100, Toralf Förster wrote:
> > Ough, does this mean that for a multi-user scenario of 2 non-root users "A" and
> > "B" each running exactly 1 process with nice level 0 and 19 rerspectively
> > that both share ~50% of the CPU *and furthermore* that that user "B" does never
> > ever have a  chance to be nice to user "A" although his process should really
> > use only those CPU cycles not eated by any other user ?
> 
> Yes.  If you want one task group to receive less cpu cycles, you have to
> 'nice' that task group by reducing it's share.

> I think it's better to just disable fair group scheduling if it doesn't
> suit your needs.  It's not going to be everyone's cup of tea.

Yes, disabling this kernel option is much better for me as a notebook user.

BTW t I've one more question related to this topic:

Is it correct that within the scenario described above user "A" never gets more
than 50% of the CPU as soon as user "B" is logged into the system (because of
the login process itself) ?

> 	-Mike
> 



-- 
MfG/Sincerely

Toralf Förster
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