Setting up the channel measurement facility

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7.1 LPAR mode z/VM guest

Configure the channel measurement facility by adding parameters to the kernel parameter file.

You can configure the channel measurement facility by adding parameters to the kernel parameter file.

Figure 1. Channel measurement facility kernel parameters

1! cmf.format=-1
1 cmf.format=
2.1 0
2.1 1
1! cmf.maxchannels=1024
1 cmf.maxchannels=<no_channels>
where:
cmf.format
defines the format, 0 for basic and 1 for extended, of the channel measurement blocks. The default, -1, uses the extended format.
cmf.maxchannels=<no_channels>
limits the number of devices for which data measurement can be enabled concurrently with the basic format. The maximum for <no_channels> is 4096. A warning will be printed if more than 4096 channels are specified. The channel measurement facility might still work; however, specifying more than 4096 channels causes a high memory consumption.

For the extended format there is no limit and any value you specify is ignored.