Abstract: A computer-implemented method for message handling between a receiver and a sender of a throttling system is provided. The computer-implemented method includes receiving a first message that includes a completion queue element by the receiver from the sender. The computer-implemented method includes detecting that a number of outstanding completion queue elements in a completion queue meets or exceeds a high mark and instructing the sender to enter a throttle mode. The computer-implemented method includes receiving a second message without a completion queue element by the receiver from the sender. The computer-implemented method includes detecting that the number of the outstanding completion queue elements in the completion queue meets or is below a low mark and instructing the sender to exit the throttle mode.

Abstract: A computer-implemented method for message handling between a receiver and a sender of a throttling system is provided. The computer-implemented method includes receiving a first message that includes a completion queue element by the receiver from the sender. The computer-implemented method includes detecting that a number of outstanding completion queue elements in a completion queue meets or exceeds a high mark and instructing the sender to enter a throttle mode. The computer-implemented method includes receiving a second message without a completion queue element by the receiver from the sender. The computer-implemented method includes detecting that the number of the outstanding completion queue elements in the completion queue meets or is below a low mark and instructing the sender to exit the throttle mode.

Abstract: A system and method for correlating asynchronous operations via an operation identifier comprises receiving an originating operation from a first system that indicates a change in the first system and generating a first message with respect to the originating operation. The first message is associated with the operation identifier. The system and method further propagates the first message to a second system, which causes a subsequent operation being associated with the operation identifier to be performed by the second system, and correlates the originating operation and the subsequent operation via the operation identifier.

Abstract: A system and method for correlating asynchronous operations via an operation identifier comprises receiving an originating operation from a first system that indicates a change in the first system and generating a first message with respect to the originating operation. The first message is associated with the operation identifier. The system and method further propagates the first message to a second system, which causes a subsequent operation being associated with the operation identifier to be performed by the second system, and correlates the originating operation and the subsequent operation via the operation identifier.

Abstract: Embodiments relate to path selection for packet transfer in a network. An aspect includes a method of selecting a path among a plurality of paths in a network for transfer of a packet from a first system to a second system in the network. The method includes storing, in a memory device, a static path performance vector indicating a tier among a plurality of tiers corresponding with each of the plurality of paths, each of the plurality of tiers corresponding with a relative performance level. The method also includes maintaining a path availability bit vector indicating an availability of each of the plurality of paths, and selecting, using a processor, the path among the plurality of paths based on the path performance vector and the path availability bit vector.

Abstract: Embodiments relate to path selection for packet transfer in a network. An aspect includes a method of selecting a path among a plurality of paths in a network for transfer of a packet from a first system to a second system in the network. The method includes storing, in a memory device, a static path performance vector indicating a tier among a plurality of tiers corresponding with each of the plurality of paths, each of the plurality of tiers corresponding with a relative performance level. The method also includes maintaining a path availability bit vector indicating an availability of each of the plurality of paths, and selecting, using a processor, the path among the plurality of paths based on the path performance vector and the path availability bit vector.

Abstract: Embodiments relate to path selection for packet transfer in a network. An aspect includes a method of selecting a path among a plurality of paths in a network for transfer of a packet from a first system to a second system in the network. The method includes storing, in a memory device, a static path performance vector indicating a tier among a plurality of tiers corresponding with each of the plurality of paths, each of the plurality of tiers corresponding with a relative performance level. The method also includes maintaining a path availability bit vector indicating an availability of each of the plurality of paths, and selecting, using a processor, the path among the plurality of paths based on the path performance vector and the path availability bit vector.

Abstract: Embodiments relate to path selection for packet transfer in a network. An aspect includes a method of selecting a path among a plurality of paths in a network for transfer of a packet from a first system to a second system in the network. The method includes storing, in a memory device, a static path performance vector indicating a tier among a plurality of tiers corresponding with each of the plurality of paths, each of the plurality of tiers corresponding with a relative performance level. The method also includes maintaining a path availability bit vector indicating an availability of each of the plurality of paths, and selecting, using a processor, the path among the plurality of paths based on the path performance vector and the path availability bit vector.

Abstract: Embodiments relate to path selection for packet transfer in a network. An aspect includes a method of selecting a path among a plurality of paths in a network for transfer of a packet from a first system to a second system in the network. The method includes storing, in a memory device, a static path performance vector indicating a tier among a plurality of tiers corresponding with each of the plurality of paths, each of the plurality of tiers corresponding with a relative performance level. The method also includes maintaining a path availability bit vector indicating an availability of each of the plurality of paths, and selecting, using a processor, the path among the plurality of paths based on the path performance vector and the path availability bit vector.

Abstract: A system and method for correlating asynchronous operations via an operation identifier comprises receiving an originating operation from a first system that indicates a change in the first system and generating a first message with respect to the originating operation. The first message is associated with the operation identifier. The system and method further propagates the first message to a second system, which causes a subsequent operation being associated with the operation identifier to be performed by the second system, and correlates the originating operation and the subsequent operation via the operation identifier.

Abstract: A system and method for correlating asynchronous operations via an operation identifier comprises receiving an originating operation from a first system that indicates a change in the first system and generating a first message with respect to the originating operation. The first message is associated with the operation identifier. The system and method further propagates the first message to a second system, which causes a subsequent operation being associated with the operation identifier to be performed by the second system, and correlates the originating operation and the subsequent operation via the operation identifier.

Abstract: Embodiments relate to path selection for packet transfer in a network. An aspect includes a method of selecting a path among a plurality of paths in a network for transfer of a packet from a first system to a second system in the network. The method includes storing, in a memory device, a static path performance vector indicating a tier among a plurality of tiers corresponding with each of the plurality of paths, each of the plurality of tiers corresponding with a relative performance level. The method also includes maintaining a path availability bit vector indicating an availability of each of the plurality of paths, and selecting, using a processor, the path among the plurality of paths based on the path performance vector and the path availability bit vector.

Abstract: A computer program product, apparatus and method for emulating channels in a multi-tasking multi-processor environment, including identifying a plurality of physical channels having an associated physical channel identifier for each of the plurality of physical channels, associating an emulated channel from a plurality of emulated channels for each of the plurality of physical channels, thereby generating a plurality of emulated channels, each of the plurality of emulated channels having a virtual channel identifier, mapping the plurality of emulated channels on a communications link, thereby generating an emulated channel path for each of the plurality of emulated channels, defining a queue pair link buffer from a plurality of queue pair link buffers for each of the emulated channels and increasing a number of queue pair link buffers.

Abstract: A computer program product for passing initiative in a multitasking multiprocessor environment includes a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method. The method includes writing a request to process a resource of the environment to an associated resource control block, setting a resource flag in a central bit vector, the resource flag indicating that a request for processing has been received for the resource, and setting a target processor initiative flag in the environment, the target processor initiative flag indicating a pass of initiative to a target processor responsible for the resource.

Abstract: A computer program product for incorporating state machine controls into existing non-state machine environments includes a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method. The method includes determining a state machine representation for an existing environment, assigning state indicators to each state of the state machine, transcoding existing software flags of the environment into modifier values associated with the state indicators, assigning state values based on the modifier values and the state indicators, assigning event identifiers for transitions from the state values, and creating a tabular representation of the determined state machine, the tabular representation providing next state information based on the event identifiers and the state values.

Abstract: Disclosed are a method and system of tracking real time use of I/O control blocks on a processing unit basis, in a multiprocessing system, such that in the case of a processing unit failure, a list accurately and concisely identifies the control blocks that need to be recovered. This eliminates the need to scan all the I/O control blocks, greatly reducing the overall system recovery time and minimizing impact to the rest of the running system. The preferred embodiment of the invention uses a task control block structure to record which I/O control blocks are in use by each Processing Unit. Also, the lock word structure defined in the I/O control blocks is provided with an index back into the task control block to facilitate managing the task control block entries.

Abstract: A computer program product for passing initiative in a multitasking multiprocessor environment includes a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method. The method includes writing a request to process a resource of the environment to an associated resource control block, setting a resource flag in a central bit vector, the resource flag indicating that a request for processing has been received for the resource, and setting a target processor initiative flag in the environment, the target processor initiative flag indicating a pass of initiative to a target processor responsible for the resource.

Abstract: A computer program product, apparatus and method for emulating channels in a multi-tasking multi-processor environment, including identifying a plurality of physical channels having an associated physical channel identifier for each of the plurality of physical channels, associating an emulated channel from a plurality of emulated channels for each of the plurality of physical channels, thereby generating a plurality of emulated channels, each of the plurality of emulated channels having a virtual channel identifier, mapping the plurality of emulated channels on a communications link, thereby generating an emulated channel path for each of the plurality of emulated channels, defining a queue pair link buffer from a plurality of queue pair link buffers for each of the emulated channels and increasing a number of queue pair link buffers.

Abstract: A computer program product, apparatus and method for buffer discovery in a multi-tasking multi-processor environment. An exemplary embodiment includes establishing a management connection, confirming that end points of the management connection are connected to respective targets, sending a negotiate counts message, including a number and size of buffers associated with parameters of the management connection and receiving a response to the negotiate counts message, the response including at least one of rejection of the management connection and an acceptance of the management connection, including an agreed number and size of the buffers.

Abstract: A computer program product for incorporating state machine controls into existing non-state machine environments includes a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method. The method includes determining a state machine representation for an existing environment, assigning state indicators to each state of the state machine, transcoding existing software flags of the environment into modifier values associated with the state indicators, assigning state values based on the modifier values and the state indicators, assigning event identifiers for transitions from the state values, and creating a tabular representation of the determined state machine, the tabular representation providing next state information based on the event identifiers and the state values.