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Lund Performance Solutions


SOS Memory Summary

The Memory Summary Screen

The Memory Summary screen provides a detailed look at memory and virtual memory performance.




Figure 11.1 SOS Memory Summary screen
To access the Memory Summary screen from any SOS display screen:
  • Type s from the SOS Enter command: prompt to view the Screen Selection Menu screen.
  • From the Screen Selection Menu screen, enter m (Memory Summary). Figure 11.1 shows an example of the screen.
  • Memory Summary Screen Display Items

    MEM/VM ALLOCATION

    The MEM/VM ALLOCATION portion of the Memory Summary screen shows how RAM and virtual memory are allocated on the system. The data items are described in the following table.
    Table 11.1 SOS MEM/VM ALLOCATION data items
    Data Item
    Description
    Mem
    Size
    Megabytes of RAM on the system.
    User
    Megabytes of RAM used by user processes.
    Sys
    Megabytes of RAM used by the operating system.
    Buffer
    Megabytes of RAM used by the buffer cache.
    Free
    Megabytes of unused RAM.
    VM
    Size
    Megabytes of virtual memory (swap space) configured on the system.
    User
    Megabytes of virtual memory used by user processes.
    Sys
    Not applicable.
    Buffer
    Not applicable.
    Free
    Megabytes of unused virtual memory.

    PROC MEM STATUS

    The PROC MEM STATUS portion of the Memory Summary screen shows where processes are currently located from a memory viewpoint. Each data item is described in the next table.
    Table 11.2 SOS PROC MEM STATUS data items
    Data Item
    Description
    Loaded
    Run
    Number of processes in memory that are able to run.
    Sleep
    Number of processes in memory that are sleeping.
    Total
    Total number of processes in memory.
    Deact
    Run
    Not applicable, since deactivated processes are not run by definition.
    Sleep
    Total
    Total number of deactivated processes.

    PAGING

    The PAGING portion of the Memory Summary screen displays detailed statistics on paging activity for the interval. Each data item is described in the following table.
    Table 11.3 SOS PAGING data items
    Data item
    Description
    Pg Flts
    In (/s)
    The number of page faults per second (see "page fault").
    Out (/s)
    A count of page faults.
    Pages
    In (/s)
    The number of page ins per second (see "page in").
    Out (/s)
    The number of page outs per second (see "page out").
    In (byte/s)
    The rate of page ins in bytes per second.
    Out (byte/s)
    The rate of page outs in bytes per second.
    #In
    The number of page ins.
    #Out
    The number of page outs.
    (De)act
    In (/s)
    The number of page ins per second that correspond with an activation (see "activation" of the Glossary).
    Out (/s)
    The number of page outs per second that correspond with a deactivation (see "deactivation" of the Glossary).
    In (byte/s)
    The rate of activations in bytes per second.
    Out (byte/s)
    The rate of deactivations in bytes per second.
    #In
    The number of activations.
    #Out
    The number of deactivations.
    VM I/O
    In (/s)
    The number of virtual memory reads per second.
    Out (/s)
    The number of virtual memory writes per second.
    In (byte/s)
    The rate of virtual memory reads in bytes per second.
    Out (byte/s)
    The rate of virtual memory writes in bytes per second.
    #In
    The number of virtual memory reads.
    #Out
    The number of virtual memory writes.
    Forks
    In (/s)
    The number of forks per second.
    Out (/s)
    Not applicable.
    In (byte/s)
    The pages paged in as a result of a fork, in bytes per second.
    Out (byte/s)
    Not applicable.
    #In
    The number of forks.
    #Out
    Not applicable.

    PAGE SCANNER

    The PAGE SCANNER portion of the Memory Summary screen displays data the page scanning process for the interval. Each data item is described in Table 11.4.
    Table 11.4 SOS PAGE SCANNER data items
    Data Item
    Description
    Page Recs
    The Page Recs value represents the number of pages reclaimed per second.
    Page Scans
    The Page Scans value represents the number of pages scanned by the page scanner per second.

    SYSV BUFFER CACHE

    The SYSV BUFFER CACHE portion of the Memory Summary screen displays the values of key buffer cache variables. Each data item is described in the following table.
    Table 11.5 SOS SYSV BUFFER CACHE data items
    Data Item
    Description
    Read Cache Hit %
    The percentage of read requests satisfied in buffer cache.
    Write Cache Hit %
    The percentage of writes not written, because of write delays, to total writes attempted. Write delays are used to decrease the number of disk writes necessary and to organize outstanding writes in a more efficient order.
    headers
    The number of buffer cache headers. If a dynamic buffer cache is configured, this number will change over time.
    size
    The current size of buffer cache. If a dynamic buffer cache is configured, this number will change over time.
    DBC min size
    Minimum size of the Dynamic Buffer Cache. If DBC is not configured, "N/A" will be displayed.
    DBC max size
    Maximum size of the Dynamic Buffer Cache. If DBC is not configured, "N/A" will be displayed.

    MEMORY MANAGEMENT CONFIG

    The MEMORY MANAGEMENT CONFIG portion of the Memory Summary screen displays the values of key memory management variables. Each data item is described in the following table.
    Table 11.6 SOS MEMORY MANAGEMENT CONFIG data items
    Data Item
    Description
    lotsfree
    The upper bound for paging. Once paging has started, it will continue until free memory (refer to "MEM/VM ALLOCATION") is larger than lotsfree.
    desfree
    The lower bound for paging. When free memory drops below desfree, paging begins.
    minfree
    The threshold at which the system considers itself to be out of memory. At this point, the system will start swapping processes.
    umem
    Unlockable memory.
    page size
    Size of pages, in bytes.

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