amepat Command

Purpose

Active Memory Expansion Planning and Advisory Tool amepat reports Active Memory Expansion (AME) information and statistics also provides advisory report that helps planning the use of Active Memory Expansion for an existing workload.

Syntax

amepat [{{[-c max_ame_cpuusage% ] | [-C max_ame_cpuusage  ]}|[  -e startexpfactor [ :stopexpfactor [ :incexpfactor ]  ]]}][ -F ][{[-t tgt_expmem_size]|[ -a ]}]
[ -n num_entries  ] [-m min_mem_gain  ] [-u minucomp_poolsize  ]
[-v ] [-M] [ -N ] [-O proc=processor implementation ] [{ [-P recfile  ] | [  Duration ] | [  Interval Samples ]}]

amepat [ -N ] [-R recfile ] {[Duration] | [ Interval Samples]}

Description

Workload Planning

When considering that uses Active Memory Expansion for an existing workload, amepat can be used to provide guidance on possible Active Memory Expansion configurations for the workload. When amepat is run concurrently with an existing workload that is not using Active Memory Expansion, amepat monitors the memory usage, memory reference patterns, and data compressibility over a user-configurable time period of the workload. The tool then generate a report with a list of possible Active Memory Expansion configurations for the workload. The tool includes an estimate of the processor utilization impacts for the different Active Memory Expansion configurations.

The amepat command can be run on all versions of IBM® Power® servers that are supported by AIX 6.1, and later.

There are two key considerations when running amepat to do workload planning: The time at which to run the tool and the duration to run the tool. To get the best possible results from the tool, the tool must be run during peak utilization of the workload. It ensures that the tool captures peak of utilization and memory usage information of the workload.

To use amepat to generate a report for workload planning, a monitoring duration must be specified when starting amepat.

In addition to using amepat on workload that is not yet using Active Memory Expansion, amepat can also be run in LPARs where Active Memory Expansion is already enabled. When used in this mode, amepat provides a report of other possible Active Memory Expansion configurations for the workload.

Note: amepat requires privileged access to do Workload Planning. When a user starts the tool without the required privilege then the Workload Planning Capability is disabled (the -N flag is turned on implicitly)

Monitoring

amepat Can also be used to monitor the processor and memory utilization statistics (Disabling the workload planning capability). With this Monitoring capability, amepat just gathers processor and memory utilization statistics, does not gather the additional data that is required for generating the report for workload planning. Thus, Active Memory Expansion Modeling and Advisory reports are not generated.

When amepat is started without a duration or interval, amepat defaults to monitoring only capability, and amepat reports a snapshot of the LPAR’s memory, processor utilization.

amepat Can be started with duration and run with Monitoring only capability by using the -N flag. The -N flag disables the workload planning capability of this tool, thus disabling the data gathering process and reporting for workload planning.

Note: Both Recording and Reporting modes can be started with -N flag. The -N flag is supported both in Active Memory Expansion Enabled and Disabled Machines.

amepat Report

Following are the six different sections of report that is displayed by the amepat tool:

Command Information Section

The Command Information Section provides details about the arguments that are passed to the amepat tool, time of invocation, the total time the system is monitored and the number of samples collected.

System Configuration Section

The System Configuration Section provides details about the system configuration. The following table provides the complete list of information reported.

Table 1. System Configuration Section

Item	Description
Partition Name	Node name from where amepat is started
Processor Implementation Mode	The processor implementation mode. This field can be POWER8, POWER9, or Power10.
Number Of Logical CPUs	The total number of logical processors that are configured and active in the partition.
Processor Entitled Capacity	Capacity Entitlement of the partition, represented in the unit of number of physical processors. Note: The physical processor units can be in fractions as well, for example, 0.5 physical processor.
Processor Max. Capacity	The maximum Capacity that this partition is represented in the unit of number of physical processors Note: The physical processor units can be in fractions as well, for example, 0.5 physical processor.
True Memory	The true memory represents real physical or logical memory that is configured for this LPAR.
SMT Threads	Number of SMT threads configured in the partition. The value can be 1, 2, 4 or 8. Note: The maximum number of SMT threads per processor is based on the Power Architecture.
Shared Processor Mode	Indicates whether Shared Processor Mode is configured for this partition. The possible values are Disabled Shared Processor Mode is not configured. Enabled-Capped Shared Processor Mode is enabled and running in capped mode. Enabled-Uncapped Shared Processor Mode is enabled and running in uncapped mode.
Active Memory Sharing	Indicates whether Active Memory Sharing is Enabled or Disabled
Active Memory Expansion	Indicates whether Active Memory Expansion is Enabled or Disabled
Target Expanded Memory Size	Indicates the target expanded memory size in MB for the LPAR. The Target Expanded Memory Size is the True Memory Size that is multiplied by the Target Memory Expansion Factor. Note: This is displayed only when Active Memory Expansion is enabled
Target Memory Expansion factor	Indicates the target memory expansion factor that is configured for the LPAR. Note: This is displayed only when Active Memory Expansion is enabled

System Resource Statistics

System Resource Statistics provides details about the system resource utilization from CPU/Memory Stand point. The following table shows various statistics that are related to system resource utilization

Table 2. System Resource Statistics

Item	Description
CPU Util	The Partition's processor utilization in the units of a number of physical processors. The percentage of utilization against the Maximum Capacity is also reported. Note: If Active Memory Expansion is enabled, the processor utilization due to memory compression or decompression is also included
Virtual Memory Size	The Active Virtual Memory Size in MB. The percentage against the True Memory Size is also reported.
True Memory In-Use	This is the amount of the LPARs real physical (or logical) memory in MB. The percentage against the True Memory Size is also reported.
Pinned Memory	This represents the pinned memory size in MB. The percentage against the True Memory Size is also reported.
File Cache Size	This represents the noncomputational file cache size in MB. The percentage against the True Memory Size is also reported.
Available Memory	This represents the size of the memory available, in MB, for application execution. The percentage against the True Memory Size is also reported.

Note: For all the utilization metrics Average, Minimum and Maximum values get displayed if amepat is run with duration or interval.

Active Memory Expansion Statistics

Active Memory Expansion Statistics provides details about the Active Memory Expansion statistics. This section is only displayed if Active Memory Expansion has been enabled for the LPAR. The following table describes the various statistics that are reported

Table 3. Active Memory Expansion Statistics

Item	Description
AME processor Usage	The processor utilization for Active Memory Expansion activity in units of physical processors. It indicates the amount of processing capacity that is used for memory compression activity. The percentage of utilization against the Maximum Capacity is also reported.
Compressed Memory	The total amount of virtual memory that is compressed. This is measured in MB. The percentage against the Target Expanded Memory Size is also reported.
Compression Ratio	This represents how well the data is compressed in memory. A higher compression ratio indicates that the data compresses to a smaller size. For example, if 4 KB of data can be compressed down to 1 KB, then the compression ratio is 4.0.
Deficit Memory Size	The size of the expanded memory, in MB, deficit for the LPAR. This is only displayed if the LPAR has a memory deficit. The percentage against the Target Expanded Memory Size is also reported.

Note: The Active Memory Expansion Statistics section displays only when the tool is started in an Active Memory Expansion enabled machine. It also displays the average, minimum and maximum values of the statistics when the tool started with duration or interval.

Active Memory Expansion Modeled Statistics

Active Memory Expansion Modeled Statistics provides details about the modeled statistics for Active Memory Expansion. The following table provides the information about the modeled statistics.

Table 4. Expansion Modeled Statistics

Item	Description
Modeled Expanded Memory Size	It represents the size of expanded memory that is used to produce the modeled statistics.
Average Compression Ratio	It represents the average compression ratio of the in-memory data of the workload. This compression ratio is used to produce the modeled statistics.
Modeled Expansion Factor	It represents the modeled target memory expansion factor.
Modeled True Memory Size	It represents the modeled true memory size (real physical or logical memory)
Modeled Memory Gain	It represents the amount of memory the partition can gain by enabling Active Memory Expansion for the reported modeled expansion factor
AME processor Usage Estimate	It represents an estimate of the processor that would be used for Active Memory Expansion activity for the specified configuration. It estimates the amount of processing capacity that would be used for memory compression activity. The processor usage is reported in units of physical processors. The percentage of utilization against the Maximum Capacity is also reported. Note: This is just an estimate and must be used as guidance only. The actual usage can be higher or lower depending on the workload.
Modeled Implementation	It represents the processor implementation for which modeling is done. This is available only if the –O proc option is used.

Note: This section is displayed only when -N flag is not used and when run by a privileged user. The generation of Modeled statistics requires the Operating System to do certain simulation operations; hence the actual duration of monitoring can be higher than the user-specified monitoring time.

Recommendation

The recommendation provides details about the Active Memory Expansion configuration that would provide optimal benefits to the current running workload.

The recommendations are purely done based on the behavior during the monitoring period of the workload and hence the recommendations that are provided can be used only as guidance. The actual statistics can vary based on the actual behavior in real time of the workload.

Note: Active Memory Expansion Modeled Statistics and Recommendation are used for Workload Planning. When -N is specified both these reports is not displayed. Active Memory Expansion Statistics are reported only when running in an Active Memory Expansion Enabled System.

The amepat command can be used the System Management Interface Tool (SMIT) smit amepat fast path.

This command is restricted inside WPAR. When amepat is started without specifying duration or interval, the utilization statistics(System, AME) will not display any Average, Minimum, or Maximum values. It just displays the Current value. The processor utilization just displays the average from the system boot time.

Starting with AIX® 7.3, by default, the Active Memory Expansion feature selects the optimal page size mode based on the system configuration. By default, the amepat command duplicates the page size mode and attempts to model the workloads with the correct page sizes. Starting with the Power10 processor-based servers, by default, the amepat command models the workloads assuming that 64 KB pages are available.

Flags

Exit Status

Examples

1. To display the Active Memory Expansion Monitoring only report, enter:

   amepat

2. To monitor the workload during 16 minutes with 8-minute sampling interval and 2 samples, generate a report for Workload Planning, enter:

   amepat 8 2

3. To monitor the workload for a duration of 16 minutes and generate an Active Memory Expansion report for Workload Planning with modeled memory expansion factors between 1.5 and 3 at 0.5 incremental factor, enter:

   amepat –e 1.50:3.00:0.5 16

4. To monitor the workload for a duration of 16 minutes and generate an Active Memory Expansion report for Workload Planning with capping the modeled AME processor usage to 30%, enter:

   amepat –c 30 16

5. To monitor the workload for a duration of 16 minutes and generate an Active Memory Expansion report for Workload Planning with starting modeled memory gain of 1000 MB, enter:

   amepat –m 1000 16

6. To monitor the workload for a duration of 16 minutes and generate an Active Memory Expansion report for Workload Planning by modeling a minimum uncompressed pool size 2000 MB, enter:

   amepat –u 2000 16 

7. To use the recording mode of amepat to generate the recording file and generate reports with various filters, enter:

   Record for a duration of 60 minutes.

   amepat -R myrecord_amepat 60

   Note: The recording mode will switch itself into a background process.

   Generate Report for Workload Planning

   amepat -P myrecord_amepat

   Generate a Report for Workload Planning with the modeled memory expansion factors range between 2 to 4 with 0.5 delta factor

   amepat -e 2.0:4.0:0.5 -P myrecord_amepat

   Generate Monitoring report only

   amepat -N -P myrecord_amepat

8. To disable Workload Planning Capability and monitor the system for 30 minutes, enter:

   amepat -N 30

9. To monitor the workload for a duration of 60 minutes and to model for Processor Implementation P8, enter the following command:

   amepat –O proc=P8  60