CPU Ready time

[Former Member]

Hi everyone

we making load test on our enviroment (many application server, one db-server, all on vmware esx 5.5) and Monitoring, inter alia, the cpu ready time on the db-Server vitual machine. the Tools to Monitor are the wily introscope (hostagent/sap oscol on the guest host) and esxtop/vCenter on the vmware-side.

Now we have different results:

on wily, we see the timeframe of tests with Peaks from 400 to 600 % (ok --> value is *10)

On a snapshot with esxtop at 14:58 (highst load on wily), we have a readytime on the same vm of 0.78%

And on vCenter, we dont see any heavy load on the vm during the load test.

Which values are correct? Is hostagent/sap oscol meassurement are correct? i have the guess, that the hostagent collect wrong data.

Any explanations about the behaviour?

Regards

Thomas

[former_member226644 · Accepted solution]

Hello Thomas,

we have investigated this behavior. In the VMware tools Guest SDK 5.5, there is only the "Steal Time" metric. This metric is used to generate an approximate ready time. This number should be comparable to "ready time" seen in vCenter and on the ESXi host.

In the investigation, we found out, that this is not true for all occasions, since "ready time" includes some metrics, which are not found in "steal time".

That means, that there can be a difference between these two numbers and in doubt, always use the one seen in vCenter or on the ESXi host.

In the new releases of ESXi (5.5u3 and 6.0) a new metric was introduced, "contention time" this metric is more accurate and will also be enhanced if needed, like when new datapoint have to be used, to increase the accuracy of it.

So, as for now, please use the SHA/SAPOSCOL numbers as an indicator for you. If this number goes up, check the "ready time" in the vCenter for the final conclusion.

Best regards

Sebastian Lenz

VMware