Abstract: Devices and techniques for continuous in-memory versioning are described herein. A memory subsystem includes a memory device configured to store a first data unit, a second data unit, and a third data unit, wherein the first, second, and third data units have a set of physical memory locations on the memory device, and metadata associated with the first, second, and third data units, the metadata including state information and a dirty commit timestamp; and a processing device, operatively coupled to the memory device, the processing device configured to: receive, from a host system, a first memory command associated with a logical memory address, the logical memory address mapped to the set of physical memory locations of the memory device; and in response to receiving the first memory command, perform a data operation on the first, second, or third data unit based on the state information and the dirty commit timestamp.

Abstract: Disclosed in some examples are systems, devices, machine-readable mediums, and methods for customizing an in-memory versioning mode for each memory location according to a predicted access behavior to optimize memory device performance. Usage data in a previous time period may be utilized along with policy rules to determine whether to configure a particular memory address as a zero copy or direct copy mode. For example, memory addresses that are read frequently may be configured as direct copy mode to reduce the read latency penalty. This improves the functioning of the memory system by reducing read latency for memory addresses that are frequently read but written to less frequently, and reduces write latency for memory locations that are frequently written to, but not read as frequently.

Abstract: Systems, apparatuses, and methods for memory management are described. For example, these may include a first memory level including memory pages in a memory array, a second memory level including a cache, a pre-fetch buffer, or both, and a memory controller that determines state information associated with a memory page in the memory array targeted by a memory access request. The state information may include a first parameter indicative of a current activation state of the memory page and a second parameter indicative of statistical likelihood (e.g., confidence) that a subsequent memory access request will target the memory page. The memory controller may disable storage of data associated with the memory page in the second memory level when the first parameter associated with the memory page indicates that the memory page is activated and the second parameter associated with the memory page is greater than or equal to a threshold.

Abstract: An access counter associated with a segment of a memory device is maintained. An access notification for a first line of the segment is received. An access type associated with the access notification is identified. A first value of the access counter is changed by a second value based on the access type. Based on the first value of the access counter, a memory management scheme is implemented.

Abstract: A system includes a memory device and a processing device coupled to the memory device, and the processing device is to perform operations including determining, by monitoring accesses to the memory device, a plurality of values of one or more memory usage statistics reflecting memory usage by a plurality of requestors connected to the memory sub-system; generating memory usage data by processing the plurality of values of the one or more memory usage statistics; and transmitting, to a requestor of the plurality of requestors, the memory usage data.

Abstract: Disclosed in some examples are methods, systems, memory devices, and machine-readable mediums that allows an application thread to indicate an undo logging operation when calculations are beginning that may need to be rolled back if a crash or other failure occurs. During the undo logging operation, memory writes an identified memory are done to a copy and the original value is preserved. If the undo logging operation is committed, then the copy becomes the correct value and may then be subsequently used in place of the original, or the value stored in the copy is copied to the original. If the undo logging operation is abandoned, the copy is not preserved and the value goes back to the original.

Abstract: Techniques and devices are described for embedding data in an address stream on an interconnect, such as a memory bus. Addresses in an address stream indicate at least part of a location in memory (e.g., a memory page and offset), whereas data embedded in the address stream can indicate when metadata or other information is available to lend context to the addresses in the address stream. The indication of data in the address stream can be communicated using, for example, a mailbox, a preamble message in a messaging protocol, a checksum, repetitive transmission, or combinations thereof. The indication of data can be recorded from the address stream and may later be used to interpret memory traces recorded during a test or can be used to communicate with a memory device or other recipient of the data during testing or regular operations.

Abstract: Methods, systems, and devices for access heatmap generation at a memory device are described. In some examples, a memory device may maintain a register for tracking access operation occurrence, for which access operations of an address of the memory device may be mapped to multiple fields of the register. In some cases, in response to a first access operation performed on a first address of the memory device, the memory device may increment a first field and a second field of the register and, in response to a second access operation performed on a second address of the memory device, the memory device may increment the first field and a third field of the register. In some examples, the memory device may maintain a second register having a set of fields that each indicate a respective address for which an access occurrence satisfies a threshold.

Abstract: Methods, systems, and devices for access heatmap implementations at a host device are described. A host device may leverage access operation monitoring that is performed at a memory device, including various examples of signaling and management of monitoring configurations. For example, a memory device may maintain a storage location for tracking access operation occurrence, for which access operations of a given address may be mapped to multiple fields, and for which each field may be associated with access operations of a respective subset of the addresses. In some examples, such registers may be configured or accessed based on indications (e.g., commands, requests) from a host device, which may support dynamic access operation monitoring that is responsive to various operating conditions. In some examples, the host device may perform evaluations based on such minimum values associated with respective addresses to determine a distribution of data across various portions of memory.

Abstract: Techniques and devices are described for embedding data in an address stream on an interconnect, such as a memory bus. Addresses in an address stream indicate at least part of a location in memory (e.g., a memory page and offset), whereas data embedded in the address stream can indicate when metadata or other information is available to lend context to the addresses in the address stream. The indication of data in the address stream can be communicated using, for example, a mailbox, a preamble message in a messaging protocol, a checksum, repetitive transmission, or combinations thereof. The indication of data can be recorded from the address stream and may later be used to interpret memory traces recorded during a test or can be used to communicate with a memory device or other recipient of the data during testing or regular operations.

Abstract: Various embodiments provide for one or more processor instructions and memory instructions that enable a memory sub-system to predict a schedule for migrating data between memory devices, which can be part of a memory sub-system.

Abstract: Methods, systems, and devices for performance monitoring for a memory system are described. A memory system may use a set of counters to determine state information for the memory system. The memory system may also use a set of timers to determine latency information for the memory system. In response to a request for performance information, the memory system may transmit state information, latency information, or both to a host system.

Abstract: Various embodiments provide for one or more processor instructions and memory instructions that enable a memory sub-system to copy, move, or swap data across (e.g., between) different memory tiers of the memory sub-system, where each of the memory tiers is associated with different memory locations (e.g., different physical memory locations) on one or more memory devices of the memory sub-system.

Abstract: Described apparatuses and methods balance memory-portion accessing. Some memory architectures are designed to accelerate memory accesses using schemes that may be at least partially dependent on memory access requests being distributed roughly equally across multiple memory portions of a memory. Examples of such memory portions include cache sets of cache memories and memory banks of multibank memories. Some code, however, may execute in a manner that concentrates memory accesses in a subset of the total memory portions, which can reduce memory responsiveness in these memory types. To account for such behaviors, described techniques can shuffle memory addresses based on a shuffle map to produce shuffled memory addresses. The shuffle map can be determined based on a count of the occurrences of a reference bit value at bit positions of the memory addresses. Using the shuffled memory address for memory requests can substantially balance the accesses across the memory portions.

Abstract: Methods, systems, and apparatuses related to a memory fault map for an accelerated neural network. An artificial neural network can be accelerated by operating memory outside of the memory's baseline operating parameters. Doing so, however, often increases the amount of faulty data locations in the memory. Through creation and use of the disclosed fault map, however, artificial neural networks can be trained more quickly and using less bandwidth, which reduces the neural networks' sensitivity to these additional faulty data locations. Hardening a neural network to these memory faults allows the neural network to operate effectively even when using memory outside of that memory's baseline operating parameters.

Abstract: Techniques for implementing and/or operating an apparatus, which includes a host system, a memory system, and a shared memory bus. The memory system includes a first memory type that is subject to a first memory type-specific timing constraint and a second memory type that is subject to a second memory type-specific timing constraint. Additionally, the shared memory bus is shared by the first memory type and the second memory type. Furthermore, the apparatus utilizes a first time period to communicate with the first memory type via the shared memory bus at least in part by enforcing the first memory type-specific timing constraint during the first time period and utilizes a second time period to communicate with the second memory type via the shared memory bus at least in part by enforcing the second memory type-specific timing constraint during the second time period.

Abstract: Described apparatuses and methods order memory address portions advantageously for cache-memory addressing. An address bus can have a smaller width than a memory address. The multiple bits of the memory address can be separated into most-significant bits (MSB) and least-significant bits (LSB) portions. The LSB portion is provided to a cache first. The cache can process the LSB portion before the MSB portion is received. The cache can use index bits of the LSB portion to index into an array of memory cells and identify multiple corresponding tags. The cache can also check the corresponding tags against lower tag bits of the LSB portion. A partial match may be labeled as a predicted hit, and a partial miss may be labeled as an actual miss, which can initiate a data fetch. With the remaining tag bits from the MSB portion, the cache can confirm or refute the predicted hit.

Abstract: Systems, apparatuses, and methods for predictive memory access are described. Memory control circuitry instructs a memory array to read a data block from or write the data block to a location targeted by a memory access request, determines memory access information including a data value correlation parameter determined based on data bits used to indicate a raw data value in the data block and/or an inter-demand delay correlation parameter determined based on a demand time of the memory access request, predicts that read access to another location in the memory array will subsequently be demanded by another memory access request based on the data value correlation parameter and/or the inter-demand delay correlation parameter, and instructs the memory array to output another data block stored at the other location to a different memory level that provides faster data access speed before the other memory access request is received.

Abstract: Various embodiments enable versioning of data stored on a memory device, where the versioning allows the memory device to maintain different versions of data within a set of physical memory locations (e.g., a row) of the memory device. In particular, some embodiments provide for a memory device or a memory sub-system that uses versioning of stored data to facilitate a rollback operation/behavior, a checkpoint operation/behavior, or both. Additionally, some embodiments provide for a transactional memory device or a transactional memory sub-system that uses versioning of stored data to enable rollback of a memory transaction, commitment of a memory transaction, or handling of a read or write command associated with respect to a memory transaction.

Abstract: Described apparatuses and methods form adaptive cache lines having a configurable capacity from hardware cache lines having a fixed capacity. The adaptive cache lines can be formed in accordance with a programmable cache-line parameter. The programmable cache-line parameter can specify a capacity for the adaptive cache lines. The adaptive cache lines may be formed by combining respective groups of fixed-capacity hardware cache lines. The quantity of fixed-capacity hardware cache lines included in respective adaptive cache lines may be based on the programmable cache-line parameter. The programmable cache-line parameter can be selected in accordance with characteristics of the cache workload.