Abstract: An example computer-implemented method may include receiving, by a general purpose processor, the I/O operation. The method may further include transmitting, by the general purpose processor, the I/O operation to a system assist processor. The method may further include transmitting, by the system assist processor, the I/O operation to an I/O channel for execution by the I/O channel, wherein transmitting the I/O operation to the I/O channel comprises queuing the I/O operation in the multi-queue. The method may further include executing, by the I/O channel, the I/O operation.

Abstract: Examples of techniques for processing I/O operations in a channel are disclosed. In one example implementation according to aspects of the present disclosure, a computer-implemented method may include: copying, by a system assist processor, a subchannel of the channel into a lower portion of a channel communication area responsive to receiving the I/O operation; copying, by the system assist processor, channel program information from a designated starting location in a customer memory into a control block; building, by the system assist processor, a starting channel communication area into a top portion of the control block; queuing, by the system assist processor, the control block to a queue for the channel; processing, by the channel, the I/O operation responsive to retrieving the control block from the queue.

Abstract: Examples of techniques for queuing an input/output (I/O) operation in a multi-queue are disclosed. In one example implementation according to aspects of the present disclosure, an example computer-implemented method may include receiving, by a general purpose processor, the I/O operation. The method may further include transmitting, by the general purpose processor, the I/O operation to a system assist processor. The method may further include transmitting, by the system assist processor, the I/O operation to an I/O channel for execution by the I/O channel, wherein transmitting the I/O operation to the I/O channel comprises queuing the I/O operation in the multi-queue. The method may further include executing, by the I/O channel, the I/O operation.

Abstract: Examples of techniques for processing I/O operations in a channel are disclosed. In one example implementation according to aspects of the present disclosure, a computer-implemented method may include: copying, by a system assist processor, a subchannel of the channel into a lower portion of a channel communication area responsive to receiving the I/O operation; copying, by the system assist processor, channel program information from a designated starting location in a customer memory into a control block; building, by the system assist processor, a starting channel communication area into a top portion of the control block; queuing, by the system assist processor, the control block to a queue for the channel; processing, by the channel, the I/O operation responsive to retrieving the control block from the queue.

Abstract: Examples of techniques for processing I/O operations in a channel are disclosed. In one example implementation according to aspects of the present disclosure, a computer-implemented method may include: copying, by a system assist processor, a subchannel of the channel into a lower portion of a channel communication area responsive to receiving the I/O operation; copying, by the system assist processor, channel program information from a designated starting location in a customer memory into a control block; building, by the system assist processor, a starting channel communication area into a top portion of the control block; queuing, by the system assist processor, the control block to a queue for the channel; processing, by the channel, the I/O operation responsive to retrieving the control block from the queue.

Abstract: A computer system includes memory divided into a plurality of logical partitions (LPARs), each LPAR running one of a plurality of instances of an operating system (O/S). The system also includes a processor configured to run a hypervisor program to manage operation of the plurality of LPARs. The processor determines a reference I/O service time of an I/O operation on a server, measures an actual I/O service time of the operation, and determines a delay time of virtualization on the server based on the reference I/O service time and the actual I/O service time.

Abstract: A method includes determining a reference I/O service time of an I/O operation on a server and measuring, with a processor of the server running a hypervisor configured to manage a plurality of logical partitions (LPARs), each LPAR running one of a plurality of instances of an operating system (O/S), an actual I/O service time of the I/O operation. The method also includes determining, by the processor, a delay time of virtualization on the server based on the reference I/O service time and the actual I/O service time.

Abstract: A computer system includes a processor configured for detecting initial command response times of a plurality of paths for transmitting signals from the processor to one or more external devices via a plurality of channels, assigning weighted values to the plurality of paths based on the detected initial command response times, and modifying a frequency at which respective paths among the plurality of paths are selected for transmitting the signals based on the weighted values assigned to the respective paths.

Abstract: A computer system includes memory divided into a plurality of logical partitions (LPARs), each LPAR running one of a plurality of instances of an operating system (O/S). The system also includes a processor configured to run a hypervisor program to manage operation of the plurality of LPARs. The processor determines a reference I/O service time of an I/O operation on a server, measures an actual I/O service time of the operation, and determines a delay time of virtualization on the server based on the reference I/O service time and the actual I/O service time.

Abstract: A method includes determining a reference I/O service time of an I/O operation on a server and measuring, with a processor of the server running a hypervisor configured to manage a plurality of logical partitions (LPARs), each LPAR running one of a plurality of instances of an operating system (O/S), an actual I/O service time of the I/O operation. The method also includes determining, by the processor, a delay time of virtualization on the server based on the reference I/O service time and the actual I/O service time.

Abstract: A computer system includes a processor configured for detecting initial command response times of a plurality of paths for transmitting signals from the processor to one or more external devices via a plurality of channels, assigning weighted values to the plurality of paths based on the detected initial command response times, and modifying a frequency at which respective paths among the plurality of paths are selected for transmitting the signals based on the weighted values assigned to the respective paths.