linux-kernel - [PATCH] limit CPU time spent in kipmid

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Date:	Thu, 19 Mar 2009 17:27:45 +0100
From:	Martin Wilck <martin.wilck@...itsu-siemens.com>
To:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Corey Minyard <minyard@....org>,
	openipmi-developer@...ts.sourceforge.net
Subject: [PATCH] limit CPU time spent in kipmid

Hello Corey, hi everyone,

here is a patch that limits the CPU time spent in kipmid. I know that it 
was previously stated that current kipmid "works as designed" (e.g. 
http://lists.us.dell.com/pipermail/linux-poweredge/2008-October/037636.html), 
yet users are irritated by the high amount of CPU time kipmid may use up 
on current servers with many sensors, even though it is "nice" CPU time. 
Moreover, kipmid busy-waiting for the KCS interface to become ready also 
prevents CPUs from sleeping.

The attached patch was developed and tested on an enterprise 
distribution kernel where it caused the CPU load of kipmid to drop to 
essentially 0 while still delivering reliable IPMI communication.

I am looking forward for comments.
Martin

-- 
Martin Wilck
PRIMERGY System Software Engineer
FSC IP ESP DEV 6

Fujitsu Siemens Computers GmbH
Heinz-Nixdorf-Ring 1
33106 Paderborn
Germany

Tel:			++49 5251 525 2796
Fax:			++49 5251 525 2820
Email:			mailto:martin.wilck@...itsu-siemens.com
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View attachment "ipmi_si_max_busy-2.6.29-rc8.diff" of type "text/x-patch" (3494 bytes)