System counters
You can use the system counters that the Performance Monitoring Infrastructure (PMI) and Tivoli® Performance Viewer collect to monitor how efficiently your system a specific machine (node) is running.
Counters for this category contain information for a machine (node).
Counter definitions
| Name | Key | Description | Granularity | Type | Level | Overhead | ID |
|---|---|---|---|---|---|---|---|
| CPUUsageSinceLastMeasurement | systemModule.cpuUtilization | The average system CPU utilization taken over the time interval since the last reading. Because the first call is required to perform initialization, a value such as 0, which is not valid, will be returned. All subsequent calls return the expected value. On SMP machines, the value returned is the utilization averaged over all CPUs. | Per node | CountStatistic | Basic | Low | 1 |
| CPUUsageSinceServerStarted | systemModule.avgCpuUtilization | The average percent CPU Usage that is busy once the server is started. | Per node | TimeStatistic | Extended | Medium | 2 |
| FreeMemory | systemModule.freeMemory | The amount of real free memory available on the system. Real memory that is not allocated is only a lower bound on available real memory, since many operating systems take some of the otherwise unallocated memory and use it for additional I/O buffering. The exact amount of buffer memory which can be freed up is dependent on both the platform and the application(s) running on it. | Per node | CountStatistic | All | Low | 3 |
![[z/OS]](../images/ngzos.svg)
The CPUUsageSinceLastMeasurement metric might include the
workload from other non-WebSphere® Application Server processes, which can lead to inaccurate measurements. The
ProcessCpuUsage counter from the JVM Runtime Module in PMI
provides a more accurate measurement of CPU usage.