Abstract: Provided are a computer program product, system, and method for using insertion points to determine locations in a cache list at which to indicate tracks in a shared cache accessed by a plurality of processors. A plurality of insertion points to a cache list for the shared cache having a least recently used (LRU) end and a most recently used (MRU) end identify tracks in the cache list. For each processor, of a plurality of processors, for which indication of tracks accessed by the processor is received, a determination is made of insertion points of the provided insertion points at which to indicate the tracks for which indication is received. The tracks are indicated at positions in the cache list with respect to the determined insertion points.

Abstract: A method for dispatching tasks on processor cores based on memory access efficiency is disclosed. The method identifies a task and a memory area to be accessed by the task. The method may use one or more of a compiler, code knowledge, and run-time statistics to identify the memory area that is accessed by the task. The method identifies multiple processor cores that are candidates to execute the task and identifies a particular processor core from the multiple processor cores that provides most efficient access to the memory area. The method dispatches the task to execute on the particular processor core that is deemed most efficient. A corresponding system and computer program product are also disclosed.

Abstract: Remote copy operations are performed to copy data from a primary storage controller to a secondary storage controller, wherein input/output (I/O) requests are received at the primary storage controller from a host both via a bus interface and a network interface while the remote copy operations are in progress, and wherein consistency groups are formed during the remote copy operations to copy the data consistently. Quiescing of I/O operations performed via the bus interface are performed while a current consistency group is being replaced by a next consistency group during the remote copy operations.

Abstract: Provided are a computer program product, system, and method for using a track format code in a cache control block for a track in a cache to process read and write requests to the track in the cache. A track format table associates track format codes with track format metadata. A determination is made as to whether the track format table has track format metadata matching track format metadata of a track staged into the cache. A determination is made as to whether a track format code from the track format table for the track format metadata in the track format table matches the track format metadata of the track staged. A cache control block for the track being added to the cache is generated including the determined track format code when the track format table has the matching track format metadata.

Abstract: Provided are a computer program product, system, and method for providing track access reasons for track accesses resulting in the release of prefetched cache resources for the track. A first request for a track is received from a process for which prefetched cache resources to a cache are held for a second request for the track that is expected. A track access reason is provided for the first request specifying a reason for the first request. The prefetched cache resources are released before the second request to the track is received. Indication is made in an unexpected released track list of the track and the track access reason for the first request.

Abstract: Provided are a computer program product, system, and method for prefetching cache resources for a write request from a host to tracks in storage cached in a cache. Cache resources held for a plurality of tracks in a write set are released before expected writes are received for the tracks in the write set. Cache resources for tracks in the write set are obtained, following the release of the cache resources, to use for expected write requests to the tracks in the write set.

Abstract: Provided are a computer program product, system, and method for providing track access reasons for track accesses resulting in the release of prefetched cache resources for the track. A first request for a track is received from a process for which prefetched cache resources to a cache are held for a second request for the track that is expected. A track access reason is provided for the first request specifying a reason for the first request. The prefetched cache resources are released before the second request to the track is received. Indication is made in an unexpected released track list of the track and the track access reason for the first request.

Abstract: Provided are a computer program product, system, and method for generating a chain of a plurality of write requests including a commit wait flag and plurality of write requests. The commit wait flag is set to one of an indicated first value or a second value. The commit wait flag is set to the first value to cause a storage server to process the write requests by requiring a current write request being processed to complete before transferring data for a next write request following the current write request. The commit wait flag is set to the second value to cause the storage server to process the write requests by transferring data for the next write request before completing the current write request preceding the next write request. The write request chain is sent to the storage server to apply the write requests to the storage.

Abstract: Provided are a computer program product, system, and method for populating a second cache with tracks from a first cache when transferring management of the tracks from a first node to a second node. Management of a first group of tracks in the storage managed by the first node is transferred to the second node managing access to a second group of tracks in the storage. After the transferring the management of the tracks, the second node manages access to the first and second groups of tracks and caches accessed tracks from the first and second groups in the second cache of the second node. The second cache of the second node is populated with the tracks in a first cache of the first node.

Abstract: Provided are techniques for adjusting a dispatch ratio for dispatching tasks from multiple queues. The dispatch ratio is set for each queue of a plurality of queues. A number of Central Processing Unit (CPU) cycles used by tasks from each of the plurality of queues during the interval is tracked. A CPU high percentage is determined that indicates a percentage of CPU cycles used by high priority tasks. In response to determining that the CPU high percentage is below a high threshold, a new dispatch ratio is calculated that indicates an increased number of high priority tasks are to be dispatched, and the new dispatch ratio is based on the CPU high percentage, the high threshold, and a current dispatches high value. The increased number of high priority tasks are dispatched from the high priority queue based on the new dispatch ratio during a new interval.

Abstract: A computer-implemented method for transferring a reserve to a target host, according to one embodiment, includes granting to a source system, by a control unit, a reserve for a volume of a storage device. A push reserve command is received from the source system. The push reserve command specifies: a transfer of the reserve to a target system, parameter data identifying the target system, and path information specifying the source system. The reserve is transferred only to the target system in response to release of the reserve by the source system.

Abstract: Provided are techniques for adjusting a dispatch ratio for dispatching tasks from multiple queues. The dispatch ratio is set for each queue of a plurality of queues. A number of Central Processing Unit (CPU) cycles used by tasks from each of the plurality of queues during the interval is tracked. A CPU high percentage is determined that indicates a percentage of CPU cycles used by high priority tasks. In response to determining that the CPU high percentage is below a high threshold, a new dispatch ratio is calculated that indicates an increased number of high priority tasks are to be dispatched, and the new dispatch ratio is based on the CPU high percentage, the high threshold, and a current dispatches high value. The increased number of high priority tasks are dispatched from the high priority queue based on the new dispatch ratio during a new interval.

Abstract: A computer program product, system, and method for managing adding of accessed tracks in cache to a most recently used end of a cache list. A cache list for the cache has a least recently used (LRU) end and a most recently used (MRU) end. Tracks in the cache are indicated in the cache list. A track in the cache indicated on the cache list is accessed. A determination is made as to whether a track cache residency time since the accessed track was last accessed while in the cache list is within a region of lowest track cache residency times. A flag is set for the accessed track indicating to indicate the track at the MRU end in response to determining that the track cache residency time of the accessed track is within the region of lowest track cache residency times. The accessed track remains at a current position in the cache list before being accessed after setting the flag.

Abstract: Provided are a computer program product, system, and method for indicating extents of tracks in mirroring queues based on information gathered on tracks in extents in cache. Extent information on an extent of tracks in a cache indicated in an active cache list is processed in response to destaging a track from the active cache list to add to a demote list used to determine tracks to remove from the cache. The extent information is related to a number of modified tracks in an extent destaged from the active cache list. The extent information for the extent is used to determine one of a plurality of mirroring queues to indicate the extent including modified tracks. A mirroring queue having a higher priority than another mirroring queue is processed at a higher rate to determine extents of tracks to mirror from the cache to the secondary storage.

Abstract: Provided are a computer program product, system, and method for using mirroring cache list to demote modified tracks from cache A modified track for a primary storage stored in the cache to mirror to a secondary storage is indicated in a mirroring cache list. The mirroring cache list is processed to select modified tracks in the cache to transfer to the secondary storage that have not yet been transferred. The selected modified tracks in the cache are transferred to the secondary storage. The mirroring cache list is processed to determine modified tracks in the cache to demote from the cache.

Abstract: Provided are a computer program product, system, and method for using a mirroring cache list to mirror modified tracks for a primary storage in a cache to a secondary storage. Indication is made of a modified track for the primary storage stored in the cache in a mirroring cache list. The mirroring cache list is processed to select modified tracks in the cache to transfer to the secondary storage that have not yet been transferred. The selected modified tracks are transferred to the secondary storage. Indication of a modified track is removed from the mirroring cache list in response to demoting the modified track from the cache.

Abstract: One general aspect of device reservation state synchronization in accordance with the present description, device reservation management logic ensures synchronization of reservation states of primary and secondary volumes of a mirror relationship in the event of a change in the state of the mirroring relationship such as achieving full data synchronization between the volumes. Other features and aspects may be realized, depending upon the particular application.

Abstract: A method for dispatching tasks on processor cores based on memory access efficiency is disclosed. The method identifies a task and a memory area to be accessed by the task. The method may use one or more of a compiler, code knowledge, and run-time statistics to identify the memory area that is accessed by the task. The method identifies multiple processor cores that are candidates to execute the task and identifies a particular processor core from the multiple processor cores that provides most efficient access to the memory area. The method dispatches the task to execute on the particular processor core that is deemed most efficient. A corresponding system and computer program product are also disclosed.

Abstract: Provide a computer program product, system, and method for adjusting insertion points used to determine locations in a cache list at which to indicate tracks based on number of tracks added at insertion points. There are a plurality of insertion points to a cache list for the cache having a least recently used (LRU) end and a most recently used (MRU) end. Each insertion point of the insertion points identifies a track in the cache list. A plurality of tracks are indicated at positions in the cache list with respect to insertion points. For each track indicated at an insertion point of the insertion points, at least one insertion point counter for at least one insertion point with respect to the insertion point at which the track is indicated is incremented. A plurality of the insertion points are adjusted to point to different tracks in the cache list based on insertion point counters for the insertion points.

Abstract: Provided are a computer program product, system, and method for invalidating track format information for tracks in cache. Demoted tracks demoted from the cache are indicated in a demoted track list. Track format information is saved for the demoted tracks. The track format information indicates a layout of data in the demoted tracks, wherein the track format information for the demoted tracks is used when the demoted tracks are staged back into the cache. An operation is initiated to invalidate a metadata track of the metadata tracks in the storage. Demoted tracks indicated in the demoted track list having metadata in the metadata track to invalidate are removed. The track format information for the demoted tracks having metadata in the metadata track to invalidate is removed.