This week my client faced a weird
situation, the CPU utilization of theirs ESXi host were over 100% !!!
Just as informational, the high utilization
on their VMs, which caused the hosts to have a high CPU utilization, was not
VMware related ; )
We know the hosts were in a high
utilization period, but how was be over 100% possible ?
I started looking at vSphere Monitoring andPerformance, on page 49 I found a nice description of the CPU
utilization.
NOTE If a PCPU
is running at frequency that is higher than its nominal (rated) frequency, then
PCPU USED(%) can be greater than 100%.
Now that I confirmed that it’s possible, I
decided to look for what could be allowing that.
Very soon I figured out that it’s a feature
on Intel processors called Intel® Turbo Boost Technology.
When it’s enabled it allows the processor to
transition to a higher frequency in order to give more horsepower during peak
periods.
I hope you don’t have to face extreme
situations like this, but if you do that’s how you explain it to your boss.
