IPMI CPU Usage on 1950

Matt Domsch Matt_Domsch at dell.com
Thu Dec 14 15:10:12 CST 2006


On Thu, Dec 14, 2006 at 03:48:14PM -0500, Matt Saladna wrote:
> Hi everyone,
> 	We are migrating from the Poweredge 1600 platform to 1950 with the
> fifth generation RAC.  After setting up CentOS 4.4, installing OMSA 5.1,
> building the 2.6.19 kernel with IPMI support, and configuring DRAC's
> watchdog to check in 480 second intervals, CPU usage seems extremely
> high on the kernel's IPMI daemon:
> 
> The same high CPU behavior appears in CentOS 4.4's 2.6.9 kernel with
> OMSA's DKMS-built IPMI modules.  This server has been sitting idle since
> last reboot.  Is this normal for IPMI?  It seems as if something is
> wrong, but sadly I have never ventured down the IPMI path before.

Yes, it's expected.  The thread runs at idle priority and lets anything
else that wants to run do so; but when there's outstanding IPMI
commands, it spins in the CPU waiting on the response.  This greatly
speeds up command processing, at the expense of idle CPU time.
Without it, simple commands like 'ipmitool sensor list' takes over a minute
and firmware updates takes 15 minutes.  With the thread the sensor
list takes seconds and the firmware update takes just over a minute as
expected.

Thanks,
Matt

-- 
Matt Domsch
Software Architect
Dell Linux Solutions linux.dell.com & www.dell.com/linux
Linux on Dell mailing lists @ http://lists.us.dell.com



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