Vmware VM_CPU_READY_MS metric wrongly collects Aggregated (summation) data

Products

• DX Unified Infrastructure Management (Nimsoft / UIM)

Issue/Introduction

We are very interested in CPU Ready metric data (time when a guest VM has an unblocked thread(s) and waits for a CPU core/thread processing unit to be allocated) and have set up a static threshold for alarming. 5 Seconds cannot be a real value but seems to be a summation value and it is not useful for monitoring porpoises. 

We have figured out that the vmware probe wrongly collects aggregated data when the QOS_VMWARE_VM_CPU_READY_MS metric is enabled 

Environment

Release : 20.4

Component : UIM - VMWARE 7.18

Cause

Wrong formula for the specific metric was coded into the probe:

 

Vmware 7.18:

<readyMS>
                    active = true
                    unit = ms
                    descr = This monitor indicates the time that the virtual machine was ready, but could not get scheduled to run on the physical CPU.
                    name_label = CPU Ready (milliseconds)
                    metric_type = 1.17.1:31
                    qos__mcs = QOS_VMWARE_VM_CPU_READY_MS
                    qos_pobc = QOS_VMWARE_VM_CPU_READY_MS
                    qos_orig = QOS_VMWARE_VM_CPU_READY_MS
                    pciKey = cpu+ready+summation
                    meth = [accum val]
                    type = perf
</readyMS>

 

 

Hotfix: vmware-7.1.8-20220713.095648-6.zip

 

<readyMS>
                    active = true
                    unit = ms
                    descr = This monitor indicates the time that the virtual machine was ready, but could not get scheduled to run on the physical CPU.
                    name_label = CPU Ready (milliseconds)
                    metric_type = 1.17.1:31
                    qos__mcs = QOS_VMWARE_VM_CPU_READY_MS
                    qos_pobc = QOS_VMWARE_VM_CPU_READY_MS
                    qos_orig = QOS_VMWARE_VM_CPU_READY_MS
                    pciKey = cpu+ready+summation
                    meth = [accum val]
                    type = perf
</readyMS>

Resolution

The fix vmware-7.1.8-20220713.095648-6.zip attached to this KB contains an updated formula for the QOS_VMWARE_VM_CPU_READY_MS 

Just deploying the probe fix is enough for the new formula to kick in and gather the new data without the "summation"