SRM information

The SRM considers a number of factors in a system-wide look at resource utilization.

  • ASM Queue length
  • Percentage below 16M fixed
  • CPU utilization thresholds for demand paging analysis
  • CPU utilization
  • Demand paging rate
  • Page fault rate
  • Paging delay time thresholds for demand paging analysis
  • Ppaging delay time in milliseconds
  • Total paging rate
  • Unreferenced interval count
  • Percentage of total real storage fixed

Some SRM information commands show how the current values affect SRM adjustments to the system. In Figure 1, this information appears in the far right columns.

Figure 1. Typical output for SRM command
 SYS    >> WLM Goal mode OPT=00 SYSRES=(G1A01C,824A) <<
 RCT    _____ Field ________         __Value__ ___Low___ __High___ __Effect___
 CPGR   Common Page-in Rate                  5         2         4 *WSS-INC*
 CWSS   Common Target WKST                  50        50     32767
 RBEL   % Fixed Frames (below 16Meg)        28        82        88 *MPL-INC*
 RCPU   CPU Utilization                     55       101       101 *MPL-INC*
The possible values in the Effect column are:
blank
SRM does not use this value for decision-making, or high-low thresholds do not exist.
*MPL-INC*
Multiprogramming level is increased.
*MPL-DEC*
Multiprogramming level is decreased.
*PROCE-INC*
Number of processors enabled for I/O interruptions is increased.
*PROCE-DEC*
Number of processors enabled for I/O interruptions is decreased.
*THNK-INC*
Think time is increased.
*THNK-DEC*
Think time is decreased.
*WSS-INC*
Working set size is increased.
*WSS-DEC*
Working set size is decreased.
CPGR
Displays common area page-in rate.
Type:
Minor of SYS

This command shows how the current values affect SRM adjustments to the system.

CWSS
Displays common area target working set size in frames.
LUIC
Displays unreferenced interval count and threshold for logical swap think time adjustment.

This command displays current system-wide high UIC, as well as the happy values used to adjust the system think time, which the THNK minor of SYS displays.

RBEL
Displays percent of real storage less than 16 MB fixed.

This command shows how the current values affect SRM adjustments to the system.

RCPR
Displays average percentage CPU utilization as calculated by RMF™.

This command displays the average percent CPU utilization computed by RMF. To use this command, RMF API support must be installed. In addition, the Monitor I CPU report must be active.

RCPU
Displays CPU utilization.

This command shows how the current values affect SRM adjustments to the system.

In an LPAR environment, SRM does not take into account LPAR non-dispatch time, which can lead to inflated values being reported. Use the RCPR command instead.

RCT
Provides title line.

RCT provides a title line under which the output for the rest of the commands described in this section can appear.

The Low and High values come from the user’s PARMLIB. The Effect column states how the current values affect SRM adjustments to the system.

RCTA
Displays current SRM averages.

RCTA displays the Unreferenced Interval Count (UIC), page fault rate, CPU utilization, and ASMQ average values. The ASMQ is a queue of page I/O requests that are unserviced or incomplete.

The SRM averages these values over the last MPL adjustment interval. In an LPAR environment, SRM does not take into account LPAR non-dispatch time, which can lead to inflated values being reported. Use the RCPR command instead.

The average CPU utilization value calculated by the SRM varies from 0 to 100 percent, even if there are two or more processors active. The value is a utilization for the system as a whole. This value can actually be set by the SRM to 128 percent. This is a signal that, during the previous SRM interval, none of the processors ever entered the wait state, and more work (up to 28 tasks) is waiting for the CPU.

RCTH
Displays current SRM high thresholds.

UIC, paging, CPU utilization, and ASMQ high values appear.

The ASMQ is a queue of page I/O requests that are unserviced or incomplete.

The SRM averages this value over the last 20 seconds.

RCTI
Displays number of samples.

Usually thirty samples are taken.

RCTL
Displays current SRM low thresholds.

Unreferenced Interval Count (UIC), paging, CPU utilization, and ASMQ low values appear.

The ASMQ is a queue of page I/O requests that are unserviced or incomplete.

The SRM averages this value over the last 20 seconds.

RPAG
Displays page fault rate.

The page fault rate is the sum of page-ins and reclaims.

This command shows how the current values affect SRM adjustments to the system.

RREA
Displays percent of total real storage fixed.

This command shows how the current values affect SRM adjustments to the system.

RTPG
Displays total paging rate.
RTPI
Displays percent of I/O interrupts handled via TPI.

This command shows how the current values affect SRM adjustments to the system.

RUIC
Displays unreferenced interval count.

This command shows how the current values affect SRM adjustments to the system.

THNK
Displays system think time for logical swapping.