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Subject: Re: [Patch] task interactivity calculation (was
	Strange	interactivity behaviour)
From: Mike Galbraith <efault@gmx.de>
To: Martin Andersson <martin.andersson@control.lth.se>
Cc: linux-kernel@vger.kernel.org, torvalds@osdl.org,
       Ingo Molnar <mingo@elte.hu>, Andrew Morton <akpm@osdl.org>
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Date: Tue, 28 Feb 2006 17:28:44 +0100
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On Tue, 2006-02-28 at 16:05 +0100, Martin Andersson wrote:
>  >On Tue, 2006-02-28 at 11:33 +0100, Martin Andersson wrote:
> >>The appended patch fixes the problem mentioned in 
> >>http://lkml.org/lkml/2006/2/27/104
> >>regarding wrong truncations in the calculation of task interactivity 
> >>when the nice value is negative. The problem causes the interactivity to 
> >>scale nonlinearly and differ from examples in the code.
> 
> Hi Mike,
> 
> Point taken. Is it correct now?

Looks perfect to me.

	-Mike

> 
> /Martin
> 
> Signed-off-by: Martin Andersson <martin.andersson@control.lth.se>
> 
> diff -uprN linux-2.6.15.4.orig/kernel/sched.c linux-2.6.15.4/kernel/sched.c
> --- linux-2.6.15.4.orig/kernel/sched.c	2006-02-10 08:22:48.000000000 +0100
> +++ linux-2.6.15.4/kernel/sched.c	2006-02-28 15:49:12.000000000 +0100
> @@ -142,7 +142,8 @@
>   	(v1) * (v2_max) / (v1_max)
> 
>   #define DELTA(p) \
> -	(SCALE(TASK_NICE(p), 40, MAX_BONUS) + INTERACTIVE_DELTA)
> +	(SCALE(TASK_NICE(p) + 20, 40, MAX_BONUS) - 20 * MAX_BONUS / 40 + \
> +	INTERACTIVE_DELTA)
> 
>   #define TASK_INTERACTIVE(p) \
>   	((p)->prio <= (p)->static_prio - DELTA(p))
>