CPU (NUK_CPU)
Attributes (parameters)
The following attributes are available for this application class:
Name | Description | Unit | Default Performance Key Indicator (KPI) |
---|---|---|---|
Utilization (Utilization) | This parameter displays the percentage of CPU utilization. CPU utilization is calculated by adding user time and system time. Recommendations If your CPU utilization is high and a particular process that is important to you is not executing quickly enough, you can use the renice command to increase the process' priority. Refer to your system's documentation for information on the renice command. Range Thresholds The defaults (Warning at two consecutive hits in the 90% to 95% range and Alarm at two consecutive hits in the 95% to 100% range) are reasonable for a typical system. However, knowing the characteristics of your system and its workload will help you determine whether to change the defaults. | % | Yes |
Idle time (IdleTime) | This parameter displays the percentage of CPU time that is spent idle. | % | No |
Non VME interrupts (Interrupts) | This parameter displays the number of non-VME device interrupts. | # | No |
Load Average (Load) | This parameter displays the 1-minute load average from the uptime command. Load average is the average number of processes in the kernel's run queue during an interval (1 minute in this case). The data from this parameter is often more useful when looked at in combination with other parameters (such as CPUCpuUtil). A high load average along with low CPU utilization can indicate problems (most likely in the I/O subsystem). For most UNIX systems, the load average from the uptime command is not a pure measure of CPU use because it includes processes waiting for disk and network I/O. However, used with other parameters, CPULoad can help to identify several problems as shown in the Recommendations section below. Recommendations If your system appears to be slow, run the uptime command to check the 5-minute and 15-minute load average. (Consult your system documentation for information on the uptime command. Some systems have a different implementation of this command.) If the 15-minute load average is higher than the 1- or 5-minute load averages, then the average is falling, and the problem may resolve itself shortly. A consistently high load average can indicate performance bottlenecks in one or more of the following areas:
Because each UNIX system may have vastly different characteristics, no range thresholds have been set by default. With the combination of your experience with your system and your system documentation, you can set ranges that are useful. | # | No |
Context switches (ContextSwitches) | This parameter displays the total number of CPU context switches per second. | # | No |
Length of run queue (RunQueueSize) | This parameter displays the number of processes in the run queue (RunQueue). This parameter is more useful for systems that do not support the uptime command and therefore do not support the Load parameter. Load reports an average number of processes while RunQueueSize reports the current number of processes in the run queue.The data from this parameter is often more useful when looked at in combination with other parameters (such as Utilization). A high load along with low CPU utilization can indicate problems (most likely in the I/O subsystem). Recommendations A consistently high load can indicate performance bottlenecks in one or more of the following three areas:
Range Thresholds Because each UNIX system may have vastly different characteristics, no range thresholds have been set by default. With the combination of your experience with your system and your system documentation, you can set ranges that are useful. | # | No |
Utilization in system mode (SystemTime) | This parameter displays the percentage of CPU time spent in system mode doing system tasks, including the CPU resources consumed by calls to kernel routines. By itself, the SystemTime parameter does not give you much information. However, when combined with information from the PageOut, UserTime, and IOWaitTime parameters, you can get a better understanding of possible problems in your system.If SystemTime is high relative to UserTime, then the CPU is either executing a large number of kernel routines or your system is running out of memory. Recommendations If SystemTime and PageOut are all high, then you should try to identify which processes are causing this condition. If the offending processes are common processes that are run often, then your system’s performance could be improved by adding more memory. | % | No |
Utilization in user mode (UserTime) | This parameter displays the percentage of CPU time currently being spent in user mode commands and tasks initiated by users. A process can execute in either user mode or system mode. When in user mode, a process is executing within its own address space and does not require kernel resources. | % | No |
VM processor time utilization (vmUtilization) | This parameter displays the current load of the virtual machine's virtual processor. This parameter is not available for the remote host. This parameter appears only if the VMware tools are installed on the Linux virtual machine (guest machine). | % | No |
VM CPU limit (VMLimit) | This parameter displays the maximum processing power in GHz allowed to a virtual machine. Assigning a CPU limit ensures that this virtual machine never consumes more than a certain amount of the available processor power. By limiting the amount of processing power consumed, a portion of the processing power becomes available to other virtual machines. This parameter is not available for the remote host. This parameter appears only if the VMware tools are installed on the Linux virtual machine (guest machine). | GHz | No |
VM CPU reservation (vmReservation) | This parameter displays the minimum processing power in GHz available to a virtual machine. Assigning a CPU reservation ensures that even as other virtual machines on the same host consume shared processing power, there is still a certain minimum amount for this virtual machine. This parameter is not available for the remote host. This parameter appears only if the VMware tools are installed on the Linux virtual machine (guest machine). | GHz | No |
Time waiting for I/O (IOWaitTime) | This parameter displays the percentage of time that the CPU spends waiting for input and output operations.
Recommendations If too much paging is your system's problem, you should add more memory if possible. If you think your I/O subsystem is the problem, you could:
Because each UNIX system may have vastly different characteristics, no range thresholds have been set by default. With the combination of your experience with your system, your system's normal workload, and your system's documentation, you can set ranges that are useful. | % | No |
Collection status (_CollectionStatus) | This parameter displays the current collection status of the CPU. |
| No |
CPUDataCollector | Sets value for all the parameters of NUK_CPU application class. | Not applicable | No |
CPUDiscoveryCollector | This parameter discovers all the instances of NUK_CPU configured on the system. | Not applicable | No |
Steal Time (StealTime) | This parameter discovers the time stolen from a virtual machine. | % | No |
Guest Time (GuestTime) | This parameter discovers the time spent running KVM guest code (guest time, including guest nice). | % | No |
Utilization by idle time (UsedByIdleTime) | This parameter displays the percentage of CPU utilization. CPU utilization is calculated by using idle time with the following formula: Utilization by idle time = 100 – idle_time | % | No |