In described examples, a processor system includes a processor core generating memory transactions, a lower level cache memory with a lower memory controller, and a higher level cache memory with a higher memory controller having a memory pipeline. The higher memory controller is connected to the lower memory controller by a bypass path that skips the memory pipeline. The higher memory controller: determines whether a memory transaction is a bypass write, which is a memory write request indicated not to result in a corresponding write being directed to the higher level cache memory; if the memory transaction is determined a bypass write, determines whether a memory transaction that prevents passing is in the memory pipeline; and if no transaction that prevents passing is determined to be in the memory pipeline, sends the memory transaction to the lower memory controller using the bypass path.

Cache-based trace logging using tags in an upper cache level. A processor influxes a cache line into a first cache level from an upper second cache level. Influxing the cache line into the first cache level includes, based on the first cache level being a recording cache, the processor reading a tag that is (i) stored in the second cache level and (ii) associated with the cache line. Based on reading the tag, the processor determines whether a first value of the cache line within the second cache level has been previously captured by a trace. The processor performs one of (i) when the first value is determined to have been previously logged, following a logged value logic path when influxing the cache line; or (ii) when the first value is determined to have not been previously logged, following a non-logged value logic path when influxing the cache line.

A degree of fragmentation is determined based on a number of holes present in a storage system layout or a portion of a layout. Edges between the holes and used portions of the storage system are tabulated by scanning a storage space. The occurrences of a pattern of used/available allocation units and/or the occurrences of another pattern available/used allocation units are recognized. A fragmentation value is calculated based on occurrences of the patterns in view of the total storage space. The present fragmentation measurement system utilizes the number of occurrences of the holes in assessing fragmentation.

A cache system may include a cache to store a plurality of cache lines in a write-back mode; dirty cache line counter circuitry to store a count of dirty cache lines in the cache, increment the count when a new dirty cache line is added to the cache, and decrement the count when an old dirty cache line is written-back from the cache; dirty cache line write-back tracking circuitry to store an ordering of the dirty cache lines in a write-back order; mapping circuitry to map the dirty lines into the ordering; and controller circuity to use the mapping circuity to identify an evicted dirty cache line in the ordering and remove the evicted dirty cache line from the ordering.

Techniques are disclosed for managing metadata of a storage system. A storage control system receives data to be written to primary storage, and writes the received data together with metadata to a write cache. The storage control system destages the metadata from the write cache to a primary metadata structure which is configured to persistently store and index the metadata. The primary metadata structure comprises (i) a first data structure that is configured to accumulate the metadata destaged from the write cache and organize the accumulated metadata in blocks of metadata sorted by index keys, and (ii) a second data structure that is configured to receive the accumulated metadata from the first data structure, and organize the received metadata using an index structure that enables random-access to the metadata using the index keys.

Methods, systems, and apparatuses provide support for multiple address spaces in order to facilitate data movement. One system includes a host processor; a memory; a data fabric coupled to the host processor and to the memory; a first input/output memory manage unit (IOMMU) and a second IOMMU, each of the first and second IOMMUs coupled to the data fabric; a first root port and a second root port, each of the first and second root ports coupled to a corresponding IOMMU of the first and second IOMMUs; and a first peripheral component endpoint and a second peripheral component endpoint, each of the first and second peripheral component endpoints coupled to a corresponding root port of the first and second root ports, wherein each of the first and second root ports comprises hardware control logic operative to: synchronize the first and second root ports.

Responsive to a power-on of a memory device, an elapsed power-off time is identified based on a difference between a time at which the power-on occurred and a time at which a previous power-off of the memory device occurred. Responsive to a determination that the elapsed power-off time satisfies the elapsed time threshold criterion, a request to perform a first write operation on a memory unit of the memory device since power on is received, a performance parameter associated with the memory unit of the memory device is changed to a first parameter value that corresponds to a reduced performance level, and the write operation is performed on the memory unit of the memory device in accordance with the first parameter value that corresponds to the reduced performance level. Responsive to completion of the write operation, the performance parameter is changed to a value that corresponds to a normal performance level.

A mapping table management method, a memory control circuit unit, and a memory storage device are provided. The method includes: receiving a read command from a host system, wherein the read command indicates reading a first data stored in at least one first logical address; and searching whether a relation management information reflects that a first group static mapping table recording the first logical address is related to a dynamic mapping table. In response to a search result reflecting that the first group static mapping table is related to the dynamic mapping table, the dynamic mapping table is searched to obtain a first physical address mapped by the first logical address. And if not related, the first group static mapping table among group static mapping tables is searched to obtain a second physical address mapped by the first logical address.

Various implementations described herein relate to systems and methods for managing metadata using an in-memory journal, including determining metadata for data, storing the metadata in an in-memory journal, detecting an imminent interruption to operations of the storage device, in response to detecting the imminent interruption, program the in-memory journal to a non-volatile memory device of the storage device, detect that the operations of the storage device are being restored, and in response to detecting that the operations of the storage device are being restored, performing metadata update. The first data is read from first original areas of a non-volatile memory. The first metadata includes a first physical address for each of first new areas of the non-volatile memory. The metadata is programmed in a metadata area of the non-volatile memory device.

A hybrid memory module includes cache of relatively fast and durable dynamic, random-access memory (DRAM) in service of a larger amount of relatively slow and wear-sensitive flash memory. An address buffer on the module maintains a static, random-access memory (SRAM) cache of addresses for data cached in DRAM.