linux-kernel - Re: [patch] CFS scheduler, -v14

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Date:	Fri, 8 Jun 2007 01:29:25 +0300
From:	"S.Çağlar Onur" <caglar@...dus.org.tr>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	Ingo Molnar <mingo@...e.hu>, linux-kernel@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>,
	Mike Galbraith <efault@....de>,
	Arjan van de Ven <arjan@...radead.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	pranith-kumar_d@...torg.com
Subject: Re: [patch] CFS scheduler, -v14

Hi;

01 Haz 2007 Cum tarihinde, Linus Torvalds şunları yazmıştı: 
> Has it been hot where you are lately? Is your fan working?

First of all sorry for late reply.

For a while İstanbul is not really hot [~26 C] :) and yes fans are/seems 
working without a problem.

> Hardware that acts up under load is quite often thermal-related,
> especially if it starts happening during summer and didn't happen before
> that... ESPECIALLY the kinds of behaviours you see: the "sudden power-off"
> is the normal behaviour for a CPU that trips a critial overheating point,
> and the slowdown is also one normal response to overheating (CPU
> throttling).

According to ACPI output;

[caglar@...getsu][~]> cat /proc/acpi/thermal_zone/THRM/*
<setting not supported>
cooling mode:   passive
<polling disabled>
state:                   ok
temperature:             56 C
critical (S5):           105 C
passive:                 95 C: tc1=1 tc2=5 tsp=10 devices=0xc20deec8

105 C is critical for that CPU, for a while (this is why i reply late) i'm 
constantly monitoring the temprature under low and high load. 

Its in 50-70 C interval in normal usage/idle and 80-100 C interval under high 
load (compiling some applications, using cpuburn to test etc.), so seems it 
can handle overheating issues

But digging the kern.log shows some strange values also;

May 24 10:39:23 localhost kernel: [    0.000000] Detected 897.748 MHz 
processor. <--- 2.6.21.2-CFS-v14
...
May 30 00:59:11 localhost kernel: [    0.000000] Detected 898.726 MHz 
processor. <--- 2.6.21.2-CFS-v15
...
Jun  1 02:09:44 localhost kernel: [    0.000000] Detected 897.591 MHz 
processor. <--- 2.6.21.3-CFS-v15
...

And according to same log these slowdowns occured after i compiled/installed 
these kernel versions into system(cause these are the first appearence of 
this versions in kern.log). So as you said it seems definetly a overheating 
issue. I'll continue to test/monitor and report back if i can find anything. 
Thanks!

Cheers
-- 
S.Çağlar Onur <caglar@...dus.org.tr>
http://cekirdek.pardus.org.tr/~caglar/

Linux is like living in a teepee. No Windows, no Gates and an Apache in house!

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