Control data collection through the cmb_enable sysfs
attribute of the device.
Procedure
Use a device's cmb_enable attribute to enable, reset,
or switch off data collection.
- To enable data collection, write
1 to
the cmb_enable attribute. If data collection was already enabled,
writing 1 to the attribute resets all collected data to zero.
Issue a command of this form:
# echo 1 > /sys/bus/ccw/devices/<device_bus_id>/cmb_enable
where /sys/bus/ccw/devices/<device_bus_id> represents
the device in sysfs.
When data collection is enabled for a
device, a subdirectory /sys/bus/ccw/devices/<device_bus_id>/cmf is
created that contains several attributes. These attributes contain
the collected data.
- To switch off data collection issue a command of this form:
# echo 0 > /sys/bus/ccw/devices/<device_bus_id>/cmb_enable
When
data collection for a device is switched off, the subdirectory /sys/bus/ccw/devices/<device_bus_id>/cmf and
its content are deleted.
Example
In this example, data collection for a
device
/sys/bus/ccw/devices/0.0.b100 is already
active and reset:
# cat /sys/bus/ccw/devices/0.0.b100/cmb_enable
1
# echo 1 > /sys/bus/ccw/devices/0.0.b100/cmb_enable