MIO


The MIO service monitors the overall performance of the entire I/O subsystem, or a subset thereof, to detect I/O bottlenecks causing workload delays.

Related topic

This service provides workload (address space-related) information, which lets you detect jobs monopolizing specific devices and channel paths.

Syntax

GUID-9B8149EE-538C-4E0F-BE8E-25C58C2CF1CC-low.pngThe parameters are defined as follows:

Parameter

Description

chpid

channel path identifier

chpid1-chpid2

range of channel path identifiers; chpid1 is the lowest channel path identifier, and chpid2 is the highest channel path identifier

time

specifies the length of the sample period in seconds; the default sample period is 15 seconds, and the maximum period is 1,200 seconds

Warning

Important

If you do not specify chpid, the MIO service monitors all channel paths attached to all processors.

Examples

To display information about all channel paths, enter:

MIO

AMTO30I I/O data being gathered for 15 seconds

AMTO31I Channel Path Utilization Report
                     [1]  [2]       [3]
AMTO32I CHANNEL PATH 00 (BYTE) WAS 5% BUSY
AMTO32I CHANNEL PATH 03 (BLOCK) WAS 23% BUSY
AMTO32I CHANNEL PATH 12 (BLOCK) WAS 45% BUSY
AMTO32I CHANNEL PATH 23 (BLOCK) WAS 17% BUS

AMTO33I Processor I/O Interrupt Activity Report
            [4]           [5]             [6]
AMTO34I CPU 00 Processed 4,670 Interrupts ( 6% were through TPI)
AMTO35I Device and Logical Control Unit Report
          [7]   [8]   [9] [10] [11] [12] [13] [14] [15] [16]
AMTO36D -----------------------------------------------------
AMTO36H  Dev Volser %Bsy Qlth Seek ACYL Rate Conn Pend  Disct DAO
AMTO36I 3500           3    0    0    0
AMTO38D            ------------------   
                     [17]    [18]  [19]
AMTO38H            ASIDname ASID %Bsy
AMTO38I            CONSOLE  000A  100
AMTO36D ---------------------------------------------------------
AMTO36H  Dev Volser %Bsy Qlth Seek ACYL Rate Conn Pend  Disct  DAO
AMTO36I 858E USSA01    0    0    0    0  .20    0    0     0     0
AMTO38D            ------------------
AMTO38H            ASIDname ASID %Bsy
AMTO38I            MV60DS36 014F  100
AMTO36D ----------------------------------------------------------  
AMTO36H  Dev Volser %Bsy Qlth Seek ACYL Rate Conn Pend  DisctDAO
AMTO36I 8370 BAB327    7    0    2    1   25    4  .20     0  0
AMTO38D            ------------------
AMTO38H            ASIDname ASID %Bsy
AMTO38I            AAONS73  012A   40
AMTO38I            AAOD72B  00A6   60

Legend:

  1. channel path identifier (CHPID)
  2. type of channel path as specified during IOCP generation

    The valid path types are BLOCK, for block multiplexing paths, and BYTE, for byte multiplexing paths.

  3. percentage of time that the channel path was busy during the sample period

    Warning

    Important

    Channel paths less than 1% busy during the sample period are not reported unless specified either explicitly or implicitly (using a path range) as an operand of the MIO service.

  4. CPU identifier (CPUID) for the processor whose activity is being reported
  5. total number of I/O interrupts (including TPIs) processed by this CPU in the sample period
  6. percentage of I/O interrupts processed by this CPU that did not require a physical PSW swap (that is, were processed through the Test Pending Interrupt (TPI) instruction)
  7. device number whose activity was measured
  8. volume serial number of the device measured
  9. percentage of time that an I/O request was active for the device
  10. average number of I/O requests queued by the I/O supervisor for the device
  11. total number of head movements observed for the device during the sample period (N/A for non-DASD and fixed-head devices)
  12. average number of cylinders moved for each seek observed for the device
  13. number of I/O requests per second addressed to this device
  14. average time (in milliseconds) that the device was connected to a channel path on a per-request basis
  15. average time (in milliseconds) that each request was held, pending availability of a waiting for path, device, or control unit
  16. average time (in milliseconds) that the device was disconnected from the channel path pending a device or control unit function (seek) on a per-request basis
  17. name of an address space found to be a significant user of the device

    In this field, asterisks (*********) indicates that the address space terminated between the time that the data was collected and the time that the MDEVICE report was generated. The value *OTHERS* in this field indicates that the address space had more users during the sample period than could be listed. All activity for the overflow of users is reported as *OTHERS*.

  18. number of the address space found to be a significant user of the device
  19. percentage of the device busy time that this address space was requesting the device

 

Tip: For faster searching, add an asterisk to the end of your partial query. Example: cert*

BMC AMI Ops SYSPROG Services 6.4