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Date: Tue, 28 Feb 2006 16:05:32 +0100
From: Martin Andersson <martin.andersson@control.lth.se>
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To: Mike Galbraith <efault@gmx.de>
CC: linux-kernel@vger.kernel.org, torvalds@osdl.org,
       Ingo Molnar <mingo@elte.hu>, Andrew Morton <akpm@osdl.org>
Subject: Re: [Patch] task interactivity calculation (was Strange	interactivity
 behaviour)
References: <4402E52F.6080409@control.lth.se>	 <440426FC.6010609@control.lth.se> <1141135669.14628.27.camel@homer>
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 >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?

/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))