Destage of data for write cache

A method for coalescing a working set of data from a cache prior to destaging the data from the cache to a storage device having a plurality of addressable locations, comprising the steps of:

• selecting on data item to be a root item of data to be included in the work in g set,
• identifying additional data in the cache that will be destaged to locations in the storage device with addresses substantially adjacent to the root item of data,
• including the additional data in the working set, and
• completing the working set without including least recently accessed data awaiting destage from the cache.

A cache control circuit for coalescing a working set of data from a cache prior to destaging the data from the cache to a storage device having a plurality of addressable locations, the control circuit configured to:

• locate least recently accessed data awaiting destage from the cache,
• select a root item of data to be included in the working set, the root item of data having a lower storage address on the storage device than the least recently accessed data,
• identify additional data in the cache that will be destaged to locations in the storage device with addresses substantially adjacent to the address of the root item of data,
• include the additional data in the working set, and
• complete the working set without including said least recently accessed data awaiting destage from the cache.

A cache control circuit for coalescing a working set of data from a cache prior to destaging the data from the cache to a storage device having a plurality of addressable locations, the cache control circuit configured to:

• select one data item to be a root item of data to be included in the working set,
• identify additional data in the cache that will be destaged to locations in the storage device with addresses substantially adjacent to the root item of data,
• include the additional data in the working set, and
• complete the working set without including least recently accessed data awaiting destage from the cache.

A program product, comprising:

• (a) a program configured to perform a method of coalescing a working set of data from a cache prior to destaging the data from the cache to a storage device having a plurality of addressable locations, the method comprising:
• locating least recently accessed data awaiting destage from the cache,
• selecting a root item of data to be included in the working set, the root item of data having a lower storage address on the storage device than the least recently accessed data,
• identifying additional data in the cache that will be destaged to locations in the storage device with addresses substantially adjacent to the address of the root item of data,
• including the additional data in the working set, and
• completing the working set without including said least recently accessed data awaiting destage from the cache;
• and
• (b) a signal bearing media bearing the program.

A program product, comprising:

• (a) a program configured to perform a method of coalescing a working set of data from a cache prior to destaging the data from the cache to a storage device having a plurality of addressable locations, the method comprising:
• selecting one data item to be a root item of data to be included in the working set,
• identifying additional data in the cache that will be destaged to locations in the storage device with addresses substantially adjacent to the root item of data,
• including the additional data in the working set, and
• completing the working set without including least recently accessed data awaiting destage from the cache;
• and
• (b) a signal bearing media bearing the program.