Gathering I/O Measurement Data During an I/O Operation Process

Abstract

I/O measurement data associated with the performance of an I/O operation process is gathered during the I/O process. The I/O measurement data is saved in an IRB memory location specified by a test subchannel instruction. An I/O interrupt signals the completion of the I/O operation process.

1 . A method for obtaining I/O measurement data, the method comprising: 
 in response to executing a start subchannel instruction, starting an I/O operation process;    obtaining I/O measurement data associated with the performance of the I/O operation process during the I/O operation process;    saving the obtained I/O measurement data;    generating an I/O interrupt at the completion of the I/O operation process; and    in response to executing a test subchannel instruction, storing the obtained I/O measurement data in an IRB memory location specified by the test subchannel instruction.    
   
   
       2 . The method according to  claim 1  wherein the stored measurement data comprises a device connect time field, a function pending time field, a device disconnect time field, a control unit queuing time field, a device active only time field, a device busy time field and an initial command response time field.  
   
   
       3 . The method according to  claim 1  wherein I/O operation is associated with a subchannel wherein the subchannel provides a logical appearance of an I/O device to a program, the subchannel is associated with an I/O device and provides information concerning the associated I/O device and I/O operations and functions involving the associated I/O device.  
   
   
       4 . The method according to  claim 1  wherein I/O operation is associated with a subchannel wherein the subchannel comprises internal storage.  
   
   
       5 . The method according to  claim 1  wherein the saving the obtained I/O measurement data step saves the data in an internal control block with a subchannel.  
   
   
       6 . The method according to  claim 1  wherein the I/O operation is associated with a z/Architecture subchannel.  
   
   
       7 . The method according to  claim 1  comprising the further steps of: 
 in response to executing a modify subchannel instruction, storing a measurement block address of a subchannel of a channel subsystem, the measurement block address directly specifying a location in memory of a measurement block assigned to the subchannel;    obtaining measurement data the measurement data related to the performance of the I/O operation of the subchannel, the measurement data comprising device busy time, wherein device busy time is the sum of time intervals when a subchannel is device busy during an attempt to initiate any one of a start function or a resume function at the subchannel; and    storing the obtained measurement data comprising a device busy time in the measurement block specified by the measurement block address, the measurement block comprising a device busy time field.    
   
   
       8 . The method according to  claim 1  comprising the further steps of: 
 obtaining measurement data, measurement data related to a plurality of secondary queues (logical control unit queues) of a channel subsystem, the measurement data comprising queuing statistics and measurement information for one or more channels attached to the plurality of secondary queues;    executing a store secondary queue measurement data instruction having a command request block, the command request block comprising information specifying a range of secondary queues of the plurality of secondary queues;    for each secondary queue of the specified range of secondary queues, creating one or more extended secondary measurement blocks, the extended secondary measurement blocks comprising the measurement data; and    in response to executing the store secondary queue measurement data instruction, storing the created one or more extended secondary measurement blocks at a memory address block directly specified by the store secondary queue measurement data instruction.    
   
   
       9 . A computer program product for obtaining I/O measurement data, the computer program product comprising: 
 a storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising:    in response to executing a start subchannel instruction, starting an I/O operation process;    obtaining I/O measurement data associated with the performance of the I/O operation process during the I/O operation process;    saving the obtained I/O measurement data;    generating an I/O interrupt at the completion of the I/O operation process; and    in response to executing a test subchannel instruction, storing the obtained I/O measurement data in an IRB memory location specified by the test subchannel instruction.    
   
   
       10 . The computer program product according to  claim 9  wherein the stored measurement data comprises a device connect time field, a function pending time field, a device disconnect time field, a control unit queuing time field, a device active only time field, a device busy time field and an initial command response time field.  
   
   
       11 . The computer program product according to  claim 9  wherein I/O operation is associated with a subchannel wherein the subchannel provides a logical appearance of an I/O device to a program, the subchannel is associated with an I/O device and provides information concerning the associated I/O device and I/O operations and functions involving the associated I/O device.  
   
   
       12 . The computer program product according to  claim 9  wherein I/O operation is associated with a subchannel wherein the subchannel comprises internal storage.  
   
   
       13 . The computer program product according to  claim 9  wherein the saving the obtained I/O measurement data step saves the data in an internal control block with a subchannel.  
   
   
       14 . The computer program product according to  claim 9  wherein the I/O operation is associated with a z/Architecture subchannel.  
   
   
       15 . A system for obtaining I/O measurement data, the system comprising: 
 a memory;    a computer system in communication with the memory, The computer system comprising an instruction fetching unit for fetching instructions from memory and one or more execution units for executing fetched instructions;    wherein the computer system includes instructions to execute a method comprising:    in response to executing a start subchannel instruction, starting an I/O operation process;    obtaining I/O measurement data associated with the performance of the  1 /O operation process during the I/O operation process;    saving the obtained I/O measurement data; generating an I/O interrupt at the completion of the I/O operation process; and    in response to executing a test subchannel instruction, storing the obtained I/O measurement data in an IRB memory location specified by the test subchannel instruction.    
   
   
       16 . The system according to  claim 15  wherein the stored measurement data comprises a device connect time field, a function pending time field, a device disconnect time field, a control unit queuing time field, a device active only time field, a device busy time field and an initial command response time field.  
   
   
       17 . The system according to  claim 15  wherein I/O operation is associated with a subchannel wherein the subchannel provides a logical appearance of an I/O device to a program, the subchannel is associated with an I/O device and provides information concerning the associated I/O device and I/O operations and functions involving the associated I/O device.  
   
   
       18 . The system according to  claim 15  wherein I/O operation is associated with a subchannel wherein the subchannel comprises internal storage.  
   
   
       19 . The system according to  claim 15  wherein the saving the obtained I/O measurement data step saves the data in an internal control block with a subchannel.  
   
   
       20 . The system according to  claim 15  wherein the I/O operation is associated with an IBM z/Architecture subchannel.