Emulation of extended input/output measurement block facilities
AssigneeInternational Business Machines Corporation
InventorsScott M. Carlson, Greg A. Dyck, Tan Lu, Kenneth J. Oakes, Dale F. Riedy, Jr., William J. Rooney, John S. Trotter, Leslie W. Wyman, Harry M. Yudenfriend
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Abstract
An Extended Input/output (I/O) measurement block facility is emulated. The facility provides for the collection of relevant I/O measurement data, and the storing for later efficient retrieval of that data in an extended measurement block. The stored data relates to the performance of an I/O subchannel.
Claims20
A method for obtaining a block of I/O measurement data, the method comprising:
- emulating the execution of a modify subchannel instruction, in the emulated execution storing a measurement block address for 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 an 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;
- storing the obtained measurement data comprising the device busy time in the measurement block specified by the measurement block address, the measurement block comprising a device busy time field.
A computer program product for obtaining a bloc of 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:
- emulating the execution of a modify subchannel instruction, in the emulated execution storing a measurement block address for 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 an 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;
- storing the obtained measurement data comprising the device busy time in the measurement block specified by the measurement block address, the measurement block comprising a device busy time field.
A system for obtaining a block of 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:
- emulating the execution of a modify subchannel instruction, the emulated execution storing a measurement block address for 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 an 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;
- storing the obtained measurement data comprising the device busy time in the measurement block specified by the measurement block address, the measurement block comprising a device busy time field.
Dependencies are inferred from the claim text.