I see that this thread has now been viewed 99 times, but not a single response with any idea of what this %LAT_C counter is all about. I now have another example that is even worse. This VM is a Windows iSCSI target server (VSAN) with %LAT_C numbers from 60 to 88% on the VMX process. CPU is about 40%. the total of the two is consistently 110% when the VM is under load. The screenshot below totals 113.9%. See the esxtop entry below:
Power saving by the Motherboard has been suggested in other threads as being a component of this counter. However, power has been optimized:
Both of the VMs in question are high disk I/O, and while there have been spikes in Disk Latency numbers, they are averaging 7 ms or less under heavy load. This is for the VMs accessing the targets on the VSAN that is shown in the ESXTOP entry above. The VSAN itself is getting access times to the physical SAN on which it resides averaging 2-7 ms with hardly any spikes at all. I am seeing more latency introduced by this VSAN than I would like. Performance is not what it should be.
Note that the $USED of the vmx process is equal to the %LAT_C. This is creating a high $USED across the board that appears to be bogus. Even causing alarms on the VM.
You can see that it is showing 100% utilization, generating an alarm, even though the CPU utilization is only 938 Mhz. It is interesting to not that the chart does not allow higher than 100% even though the actual total utilization that we see in esxtop is 110% between these two processes. The 938 Mhz correlates to the 39.92% vcpu-0 numbers in esxtop. The screenshots were not taken at the exact same moment so the numbers are not exact.
These numbers are no longer unique on this host. High %LAT_C is being seen on all the VMs on this host. Sometimes as high as 150%. This screenshot shows a couple in the 90% range:
Can someone respond?