TOCPREVNEXTINDEX

Lund Performance Solutions


SOS Current Resource Trends
SOS/3000 has five Current Resource Trends screens that allow you to quickly see the trend of key performance areas over the duration of the current SOS/3000 session:
  • CPU Utilization Trends screen (Figure 11.1)
  • Main Memory Utilization Trends screen (Figure 11.2)
  • Disc I/O Utilization Trends screen (Figure 11.3)
  • Response and Transaction Trends screen (Figure 11.4)
  • Mode Switch Trends screen (Figure 11.5)
  • Current Resource Trend Screen Keys

    Each of the Current Resource Trend Screen key is listed and explained in the following table.
    Table 11.1 Current Resource Trend Screen command keys
    Key
    Usage
    blank
    Refresh screen
    B
    Beginning data request
    C
    CPU trend data
    D
    Disc trend data
    E
    Return to SOS Global screen
    J
    Jump to new screen
    L
    Print hardcopy
    M
    Memory trend data
    S
    Jump to the SOS Screen Selection menu.
    T
    Response trend data
    V
    Live data request
    W
    Mode switches trend data
    X
    Exit
    !
    Execute shell commands
    :
    Execute shell commands
    *
    Switch function key sets
    /
    Select time request
    }
    Scroll backward request
    [
    Skip forward request
    ]
    Skip backward request

    Current Resource Trend Search Keys

    From each Current Resource Trend screen, there will be a set of search keys available for navigation.
    Table 11.2 SEARCH KEYS
    Search Key
    Description
    F1 - SCROLL AHEAD
    This key displays the next page of data.
    F2 - SCROLL BACK
    This key displays the previous page of data.
    F3 - SKIP AHEAD
    This key produces a prompt for the number of samples to skip. After entering a valid number, that number of samples will be bypassed in a forward direction. The data displayed will be from that point forward.
    F4 - SKIP BACK
    This key performs like the SKIP AHEAD. When a valid number is entered, that number of samples will be skipped backward. The data displayed will then be from that point forward.
    F5 - SELECT TIME
    This key prompts for a time at which you want to begin examining data.
    F6 - START OF DATA
    This key will take you to the first interval available in the Current Trends.
    F7 - END OF DATA
    This key will take you to the current interval.
    F8 - MAIN KEYS
    This key will return you to the main keys in the Current Trends screen.
    The SOS Resource Trend screen data items are described on the next pages.

    CPU Trends Screen

    To access the CPU Trends screen:
  • Type S from the SOS Enter command: prompt to view the Screen Selection Menu.
  • From the Screen Selection Menu, type A (Current Resource Trend Screen). A sample of this screen is shown in Figure 11.1.


  • Figure 11.1 SOS CPU Trends screen
    The CPU Trends screen presents the following CPU utilization data collected in 10-second time intervals:
  • Percentage of CPU utilized
  • Percentage of idle time
  • Response time in seconds
  • Each letter-width space on the CPU utilization bar graph represents approximately 2 percent of the CPU’s time for the current interval. The code letters correspond to the CPU activities described in Table 11.3. Where a block of spaces on the bar graph is bordered by two instances of one code letter (e.g., S...S), that corresponding activity (e.g., executing system calls and code) would account for the CPU% range bordered by the two letters. For example, in the example above, the CPU utilization for 10-second interval beginning 15:11 (the first line) shows:
  • Approximately 2 percent of CPU time was spent executing stem processes and carefully placed high priority user processes in the BS queue.
  • Approximately 42 percent of the CPU time was spent executing lower priority jobs in the ES queue.
  • Approximately 2 percent was spent managing overhead.
  • Approximately 2 percent of the time the CPU was paused while waiting for disc I/O.
  • 53 percent of the time the CPU was idle.
  • Response time for that interval averaged 0.3 seconds.
  • The code letters used in the CPU utilization bar graph are described in the next table.
    Table 11.3 CPU Trend states or activities
    Code
    Statistic
    Description
    A
    AS queue %
    The percentage of CPU time spent executing high priority system processes.
    B
    BS queue %
    The percentage of CPU time spent executing both system processes and some high priority user processes.
    C
    CS queue %
    The percentage of CPU time spent executing interactive user processes.
    D
    DS queue %
    The percentage of CPU time spent executing high priority batch jobs.
    E
    ES queue %
    The percentage of CPU time spent executing lower priority jobs.
    M
    Memory management %
    The percentage of CPU time spent managing memory.
    O
    Overhead %
    The percentage of CPU time spent managing overhead (ICS/OH and dispatch).
    P
    Paused for Disc %
    The percentage of time the CPU was paused, waiting for disk I/O.
     
    Idle %
    The space between the end of the bar and the 100% point indicates the percentage of time the CPU was idle.
     
    Resp Time
    The average response time for that interval.
    Function Keys
    The other four Current Resource Trends screens are accessed via function keys at the bottom of the CPU Utilization Trends screen. The function keys under the CPU Utilization Trends screen are shown in the following table.

    Table 11.4 CPU Utilization Trends screen function keys
    Key
    Description
    F1 - LIST HARDCOPY
    Prints a hardcopy of the displayed trend report.
    F2 - CPU TREND
    Displays the CPU Utilization Trends screen (Figure 19.1). This screen reports CPU.
    F3 - MEMORY TREND
    Displays the Main Memory Utilization Trends screen (Figure 19.2). This screen reports memory clock cycle and swaps per launch ratio.
    F4 - DISC TREND
    Displays the Disc I/O Utilization Trends screen (Figure 19.3). This screen reports Read and Write disc I/O rate and average disc queue length.
    F5 - RESPONSE TREND
    Displays the Response and Transaction Trends screen (Figure 19.4). This screen reports Transaction rates per minute.
    F6 - MODE SWITCHES
    Displays the Mode Switch Trends screen (Figure 19.5). This screen reports NM to CM and CM to NM mode switch rates.
    F7 - SEARCH KEYS
    Discussed in Table 11.2
    F8 - MAIN SCREEN
    Return to SOS/3000 main screen.

    NOTE When you exit SOS/3000 all of the Currents Trends data will be lost. If you want to review past data, see "SOSLOGX".

    Main Memory Trends Screen

    The Main Memory Trends screen displays statistics pertaining to memory utilization in 10-second time intervals.


    Figure 11.2 SOS Main Memory Utilization Trends screen
    The data items presented in the Main Memory Trends screen are described in Table 11.5.
    Table 11.5 SOS Main Memory Utilization Trends data items
    Data Item
    Description
    Page Faults/sec
    This bar graph shows the average memory page faults per second during the 10-second interval. Each character space in the bar graph represents two page faults per second. If the number exceeds the range of the graph, a greater-than character (>) will display.
    The page fault rate indicates whether or not there is adequate memory. A low number is desirable.
    Swaps/Launch
    This is the ratio of the number of swap-ins to the number of launches that occurred during the interval. This can also be a good indicator of memory pressure.
    Performance Tip
    A large swaps per launch ratio means that for every time a process came up to bat with the CPU, necessary segments were not present in main memory, and the process was disabled. A ratio consistently greater than.5 indicates a possible memory shortage. Check other memory indicators for confirmation. If your memory is indeed inadequate, you can either reduce the memory load or increase memory hardware.

    Disc I/O Utilization Trends Screen



    Figure 11.3 SOS Disc I/O Utilization Trends screen
    The data items presented in the Disc I/O Utilization Trends screen are described in Table 11.6.
    Table 11.6 SOS Disc I/O Utilization Trends data items
    Data Item
    Description
    Disc I/O rate (second)
    A total rate of both reads and writes per second (Rt). These numbers reflect the actual physical transfers between main memory and a particular disc device (Ldv-n).
    Avg Queue Length
    The average length of the request queue for that particular disc drive when another disc I/O request arrives at that drive.

    Response and Transaction Trends Screen

    Figure 11.4 SOS Response and Transaction Trends screen
    The data items presented in the Response and Transaction Trends screen are described in Table 11.7.
    Table 11.7 SOS Response and Transaction Trends data items
    Data Item
    Description
    Transaction Rate (per minute)
    This is an estimated number of terminal reads per minute based on the current interval’s workload.
    Average Response Time (sec)
    This is the average time it takes from pressing the C/R or Enter key to when the user is supplied prompt.

    Mode Switch Trends Screen



    Figure 11.5 SOS Mode Switch Trends screen
    The data items presented in the Mode Switch Trends screen are described in Table 11.8.
    Table 11.8 SOS Mode Switch Trends data items
    Data Item
    Description
    NM -> CM (per second)
    These numbers represent the number of native mode (NM) to compatibility mode (CM) switches performed per second for the current interval, as well as cumulatively.
    Performance Tip
    A native mode to compatibility mode switch occurs when a piece of code that is executed reverts from native mode language to a translated form (compatibility mode). This operation is quite expensive for the system to perform and should be minimized. Depending on the system size, about 50 per second may indicate an overhead drain on the CPU. It is best to “go native” whenever possible; but, going native can cause an increased dependency on the application design.
    CM -> NM (per second)
    These numbers represent the number of compatibility mode to native mode switches performed per second for the current interval, as well as cumulatively.
    Performance Tip
    A compatibility mode to native mode switch occurs when a piece of code that is executed reverts from compatibility mode to native mode. This operation is not as expensive to perform as is NM to CM switching. The system can sustain many more without excessive degradation to the system. Depending on the system size, more than about two hundred per second can be sustained without being an excessive overhead drain on the CPU.

    General Comments

    The default number of the intervals to be displayed for Current Trends is 1440. This number can be raised or lowered via a MAXTRENDS job control word. For example, to set this number to 600, type the following prior to running SOS/3000:
    :SETJCW MAXTRENDS=600
    This will reduce the number of stored intervals thereby reducing memory requirements. If you raise this number from the default of 1440, more intervals will be available on-line, but memory requirements will increase.

    Lund Performance Solutions
    www.lund.com
    Voice: (541) 812-7600
    Fax: (541) 812-7611
    info@lund.com
    TOCPREVNEXTINDEX