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Ryan Ferreri Honored Contributor.
Honored Contributor.
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AIX Metrics to match NMON

My AIX folks are having a hard time getting OBM performance perspective graphs to match what they are seeing in NMON, for CPU and Memory utilization. The agent is collecting a wide variety of metrics, and NMOM just uses a "simple" utilization percentage. Does anyone know what conbination of CPU and Memory metrics will produce similar performance history to what they are seeing in NMON?

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Afloresg Respected Contributor.
Respected Contributor.

Re: AIX Metrics to match NMON

Hi Ryan,

About the OA collection in AIX, for CPU, this is the criteria to get CPU Utilization:


GBL_CPU_TOTAL_UTIL
----------------------------------
Percentage of time the CPU was not idle during the interval.
This is calculated as

GBL_CPU_TOTAL_UTIL =
GBL_CPU_USER_MODE_UTIL +
GBL_CPU_SYS_MODE_UTIL
On a system with multiple CPUs, this metric is normalized. That
is, the CPU used over all processors is divided by the number of
processors online. This represents the usage of the total
processing capacity available.

GBL_CPU_TOTAL_UTIL +
GBL_CPU_IDLE_UTIL = 100%
This metric varies widely on most systems, depending on the
workload. A consistently high CPU utilization can indicate a CPU
bottleneck, especially when other indicators such as
GBL_RUN_QUEUE and GBL_ACTIVE_PROC are also high. High CPU
utilization can also occur on systems that are bottlenecked on
memory, because the CPU spends more time paging and swapping.
NOTE: On Windows, this metric may not equal the sum of the
APP_CPU_TOTAL_UTIL metrics. Microsoft states that "this is
expected behavior" because this GBL_CPU_TOTAL_UTIL metric is
taken from the performance library Processor objects while the
APP_CPU_TOTAL_UTIL metrics are taken from the Process objects.
Microsoft states that there can be CPU time accounted for in the
Processor system objects that may not be seen in the Process
objects. On a logical system, this metric indicates the logical
utilization with respect to number of processors available for
the logical system (GBL_NUM_CPU).
On platforms other than HPUX, If the ignore_mt flag is set(true)
in parm file, this metric will report values normalized against
the number of active cores in the system.
If the ignore_mt flag is not set(false) in parm file, this metric
will report values normalized against the number of threads in
the system. This flag will be a no-op if Multithreading is turned
off.


for Memory Utilization:

GBL_MEM_UTIL

On AIX, this excludes file cache when cachemem parameter in the
parm file is set to free.
Locality Domain metrics are available on HP-UX 11iv2 and above.
GBL_MEM_FREE and LDOM_MEM_FREE, as well as the memory utilization
metrics derived from them, may not always fully match.
GBL_MEM_FREE represents free memory in the kernel's reservation
layer while LDOM_MEM_FREE shows actual free pages. If memory has
been reserved but not actually consumed from the Locality
Domains, the two values won't match. Because GBL_MEM_FREE
includes pre-reserved memory, the GBL_MEM_* metrics are a better
indicator of actual memory consumption in most situations.

I hope this information helps you.

Regards.

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