Kipmi0 May Show Increased CPU Utilization on Linux

This article is takenf from IBM Support Portal. Kipmi0 May Show Increased CPU Utilization on Linux

Description

The kipmi0 process may show increased CPU utilization in Linux. The utilization may increase up to 100% when the IPMI (Intelligent Platform Management Interface) device, such as a BMC (Baseboard Management Controller) or IMM (Integrated Management Controller) is busy or non-responsive.



Fix

No fix required. You should ignore increased CPU utilization as it has no impact on actual system performance.

Work-around

1. If using an IPMI device, reset the BMC or reboot the system.

2. If not using an IPMI device, stop the IMPI service by issuing the following command:

    service ipmi stop


Details

IBM has requested that the design of kipmi be reviewed in future releases. Any changes that may occur through this review would be implemented in future Linux Distribution updates.

The increased CPU usage of kipmi is normal. The hardware interface is not interrupt driven, so the driver must poll the device for status and messages. It is this polling that is showing up as a busy CPU. The kipmi kernel thread has its priority intentionally lowered so that it does not interfere with other processes on the system. Even when it is polling in its tightest loop (usually when it thinks the BMC has active events it needs to handle), it will give up the CPU to any process that wants it.

The CPU usage seen for the kipmi0 kernel thread is what is known as IDLE time. Kipmi0 is running when there are no other jobs to run and is one of the lowest priority processes on the system.

This is the standard behavior for this interface and is not unique to this process running in an IBM environment or specifically with IBM Systems Director.