A system and method for efficiently maintaining metadata stored among a plurality of solid-state storage devices. A data storage subsystem supports multiple mapping tables. Records within a mapping table are arranged in multiple levels. Each level stores at least pairs of a key value and a physical pointer value. The levels are sorted by time. New records are inserted in a created new highest (youngest) level. No edits are performed in-place. A data storage controller determines both a cost of searching a given table exceeds a threshold and an amount of memory used to flatten levels exceeds a threshold. In response, the controller incrementally flattens selected levels within the table based on key ranges. After flattening the records in the selected levels within the key range, the records may be removed from the selected levels. The process repeats with another different key range.

A system and method for efficiently maintaining metadata stored among a plurality of solid-state storage devices. A data storage subsystem supports multiple mapping tables. Records within a mapping table are arranged in multiple levels. Each level stores at least pairs of a key value and a physical pointer value. The levels are sorted by time. New records are inserted in a created new highest (youngest) level. No edits are performed in-place. A data storage controller determines both a cost of searching a given table exceeds a threshold and an amount of memory used to flatten levels exceeds a threshold. In response, the controller incrementally flattens selected levels within the table based on key ranges. After flattening the records in the selected levels within the key range, the records may be removed from the selected levels. The process repeats with another different key range.

A server includes a data cache for storing data objects requested by mobile devices, desktop devices, and server devices, each of which may execute a different configuration of an application. When a cache miss occurs, the cache may begin loading portions of a requested data object from various data sources. The cache itself may be divided into multiple partitions, and each of the partitions may be assigned to a specific attribute, such as an application configuration. Portions of the data object may be loaded into corresponding cache partitions based on the attributes of each. Although part of a single cache, each of the partitions may be independently assigned different cache replacement policies. Performance metrics for each of the partitions may be monitored and used to update the cache replacement policy for each partition at runtime without interrupting response traffic.

A server includes a data cache for storing data objects requested by mobile devices, desktop devices, and server devices, each of which may execute a different configuration of an application. When a cache miss occurs, the cache may begin loading portions of a requested data object from various data sources. The cache itself may be divided into multiple partitions, and each of the partitions may be assigned to a specific attribute, such as an application configuration. Portions of the data object may be loaded into corresponding cache partitions based on the attributes of each. Although part of a single cache, each of the partitions may be independently assigned different cache replacement policies. Performance metrics for each of the partitions may be monitored and used to update the cache replacement policy for each partition at runtime without interrupting response traffic.

Described herein are systems and methods for cache replacement mechanisms for speculative execution. For example, some systems include, a buffer comprising entries that are each configured to store a cache line of data and a tag that includes an indication of a status of the cache line stored in the entry, in an integrated circuit that is configured to: responsive to a cache miss caused by a load instruction that is speculatively executed by a processor pipeline, load a cache line of data corresponding to the cache miss into a first entry of the buffer and update the tag of the first entry to indicate the status is speculative; responsive to the load instruction being retired by the processor pipeline, update the tag to indicate the status is validated; and, responsive to the load instruction being flushed from the processor pipeline, update the tag to indicate the status is cancelled.

Described herein are systems and methods for cache replacement mechanisms for speculative execution. For example, some systems include, a buffer comprising entries that are each configured to store a cache line of data and a tag that includes an indication of a status of the cache line stored in the entry, in an integrated circuit that is configured to: responsive to a cache miss caused by a load instruction that is speculatively executed by a processor pipeline, load a cache line of data corresponding to the cache miss into a first entry of the buffer and update the tag of the first entry to indicate the status is speculative; responsive to the load instruction being retired by the processor pipeline, update the tag to indicate the status is validated; and, responsive to the load instruction being flushed from the processor pipeline, update the tag to indicate the status is cancelled.

A storage device includes a nonvolatile memory device, a memory controller, and a buffer memory. The memory controller determines a first memory block of the nonvolatile memory device, which is targeted for a read reclaim operation, and reads target data from a target area of the first memory block. The target data are stored in the buffer memory. The memory controller reads at least a portion of the target data stored in the buffer memory in response to a read request corresponding to at least a portion of the target area.

An electronic device includes a cache with a cache controller and a cache memory. The electronic device also includes a cache policy manager. The cache policy manager causes the cache controller to use two or more cache policies for cache operations in each of multiple test regions in the cache memory, with different configuration values for the two or more cache policies being used in each test region. The cache policy manager selects a selected configuration value for at least one cache policy of the two or more cache policies based on performance metrics for cache operations while using the different configuration values for the two or more cache policies in the test regions. The cache policy manager causes the cache controller to use the selected configuration value when using the at least one cache policy for cache operations in a main region of the cache memory.

In one embodiment, storage drive dependent track removal processing logic performs destage tasks for tracks cached in a cache as a function of whether the storage drive is classified as a fast class or as slow class of storage drives, for example. In one embodiment, a destage task configured for a slow class storage drive, transfers an entry for a track selected for destaging from a main cache list to a wait cache list to await destaging to the slow class drive. A destage task configured for a fast class storage drive allows the cache list entry for the selected track to remain on the main cache list while the selected track is being destaged to the fast class storage drive, thereby bypassing the transfer of the entry to a wait cache list. Other features and aspects may be realized, depending upon the particular application.

In one embodiment, storage drive dependent track removal processing logic performs destage tasks for tracks cached in a cache as a function of whether the storage drive is classified as a fast class or as slow class of storage drives, for example. In one embodiment, a destage task configured for a slow class storage drive, transfers an entry for a track selected for destaging from a main cache list to a wait cache list to await destaging to the slow class drive. A destage task configured for a fast class storage drive allows the cache list entry for the selected track to remain on the main cache list while the selected track is being destaged to the fast class storage drive, thereby bypassing the transfer of the entry to a wait cache list. Other features and aspects may be realized, depending upon the particular application.