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How AIX Enable CPU Folding

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By default, CPU folding is enabled in AIX. A system with cpu folding disabled may look like this:

[root@primary01 /]# schedo -a | grep vpm_xvcpus
                   vpm_xvcpus = -1

Enable vpm_xvcpus

To enable it, you can set vpm_xvcpus into 0.

[root@primary01 /]# schedo -o vpm_xvcpus=0
Setting vpm_xvcpus to 0

Let's check current value of vpm_xvcpus.

[root@primary01 /]# schedo -L vpm_xvcpus
NAME                      CUR    DEF    BOOT   MIN    MAX    UNIT           TYPE
     DEPENDENCIES
--------------------------------------------------------------------------------
vpm_xvcpus                0      0      0      -1     1536   processors        D
--------------------------------------------------------------------------------

Increase vpm_xvcpus

To increase the number of virtual processors permanently, say 2 to conform to requirements of some application installation like Oracle grid infrastructure 19c, we can do this:

[root@primary01 /]# schedo -p -o vpm_xvcpus=2
Setting vpm_xvcpus to 2 in nextboot file
Setting vpm_xvcpus to 2
[root@primary01 /]# schedo -L vpm_xvcpus
NAME                      CUR    DEF    BOOT   MIN    MAX    UNIT           TYPE
     DEPENDENCIES
--------------------------------------------------------------------------------
vpm_xvcpus                2      0      2      -1     1536   processors        D
--------------------------------------------------------------------------------

The change needs a system reboot to take effect.

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