Jim Hannan (@HoBHannan), Principal Architect
This is the follow up blog to CPU Ready Part I. I have been using the following tables for around six months now. I find them very helpful in quickly determining if a virtual machine is having issues with CPU Ready Time.
What is CPU Ready Time?
CPU Ready Time is measured as a summation value in vSphere, different chart time spans will effect the redline value. Here’s a break down of the summations for each time period:
- Real-time: 20 seconds
- Past Day: 5 minutes (300 seconds)
- Past Week: 30 minutes (1800 seconds)
- Past Month: 2 hours (7200 seconds)
- Past Year: 1 day (86400 seconds)
This can be time consuming to collect during troubleshooting, so we supplied the redline for each time period in Tables 1-5.
The formula: CPU Ready % = (Summation value / (chart update interval in seconds x 1000)) x 100
Reference: Update intervals (KB article 2002181): http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2002181
Table 1 – CPU Ready Time (Real Time)
For CPU Ready Time measured by Real Time the interval is every 20 seconds.
| ms (milliseconds) | % (percent) |
| 1000 | 5.0 |
| 900 | 4.5 |
| 800 | 4.0 |
| 700 | 3.5 |
| 600 | 3.0 |
| 500 | 2.5 |
| 400 | 2.0 |
| 300 | 1.5 |
| 200 | 1.0 |
| 100 | 0.5 |
| 50 | 0.25 |
Table 2 – CPU Ready Time (Day)
For CPU Ready Time measured by Day the interval is every 300 seconds.
| ms (milliseconds) | % (percent) |
| 15000 | 5.0 |
| 13500 | 4.5 |
| 12000 | 4.0 |
| 10500 | 3.5 |
| 9000 | 3.0 |
| 7500 | 2.5 |
| 6000 | 2.0 |
| 4500 | 1.5 |
| 3000 | 1.0 |
| 1500 | 0.5 |
| 750 | 0.25 |
Table 3 – CPU Ready Time (Week)
For CPU Ready Time measured by Week the interval is every 30 minutes.
| ms (milliseconds) | % (percent) |
| 90000 | 5.0 |
| 81000 | 4.5 |
| 72000 | 4.0 |
| 63000 | 3.5 |
| 54000 | 3.0 |
| 45000 | 2.5 |
| 36000 | 2.0 |
| 27000 | 1.5 |
| 18000 | 1.0 |
| 9000 | 0.5 |
| 4500 | 0.25 |
Table 4 – CPU Ready Time (Month)
For CPU Ready Time measured by Month the interval is every 2 hours.
| ms (milliseconds) | % (percent) |
| 360000 | 5.0 |
| 324000 | 4.5 |
| 288000 | 4.0 |
| 252000 | 3.5 |
| 216000 | 3.0 |
| 180000 | 2.5 |
| 144000 | 2.0 |
| 108000 | 1.5 |
| 72000 | 1.0 |
| 36000 | 0.5 |
| 18100 | 0.25 |
Table 5 – CPU Ready Time (Year)
For CPU Ready Time measured by Year the interval is every 864000 seconds.
| ms (milliseconds) | % (percent) |
| 4320000 | 5.0 |
| 3888000 | 4.5 |
| 3456000 | 4.0 |
| 3024000 | 3.5 |
| 2592000 | 3.0 |
| 2160000 | 2.5 |
| 1728000 | 2.0 |
| 1296000 | 1.5 |
| 864000 | 1.0 |
| 432000 | 0.5 |
| 216000 | 0.25 |
