The Virtualization Cookbook for SLES 10 SP2 - z/VM - IBM

idle The current idle percentage
These CPU hot plugging and unplugging values will be used in the next section. In the default
setup, cpuplugd will only make changes to the virtual processor configuration. The auto
adaptive adjustment of the memory using the cmm feature (module) is deactivated by default
and also not available when running in a native LPAR environment.
13.7.2 Generating a workload to see cpuplugd work
You can now generate a workload to show how the cpuplugd will turn on CPUs.
Important: Running the following command will generate significant CPU use. Verify there
is not a mission-critical workload running on this z/VM LPAR, as this test may affect it.
Also, be sure to kill the processes after seeing cpuplugd in action.
Perform the following steps:
► Put ten looping jobs in the background with the following for loop:
# for i in `seq 1 10`
> do
> bash -c "cat /dev/zero > /dev/null" &
> done
[1] 2441
[2] 2442
[3] 2443
[4] 2444
[5] 2445
[6] 2446
[7] 2447
[8] 2448
[9] 2449
[10] 2453
► See that the jobs are running (you can also use the top command):
# pstree -G | grep cat
+-sshd---sshd---bash---10*[bash---cat]
► Now run lscpus every so often. The following example shows that, after a minute or so,
cpuplugd has started five of the nine spare processors.
# lscpus
/sys/devices/system/cpu/cpu0
1
/sys/devices/system/cpu/cpu1
1
/sys/devices/system/cpu/cpu2
1
/sys/devices/system/cpu/cpu3
1
/sys/devices/system/cpu/cpu4
1
/sys/devices/system/cpu/cpu5
1
/sys/devices/system/cpu/cpu6
0
/sys/devices/system/cpu/cpu7
0
/sys/devices/system/cpu/cpu8
212 The Virtualization Cookbook for RHEL 6