Abstract: The present disclosure relates to systems, methods, and computer-readable media for managing tracked memory usage data and performing various actions based on memory usage data tracked by a memory controller on a memory device. For example, systems described herein involve collecting and compiling data across one or more memory controllers to evaluate characteristics of the memory usage data to determine hotness metric(s) for segments of a memory resource. The systems described herein may perform a variety of segment actions based on the hotness metric(s). In addition, the systems described herein can compile the memory usage data according to one or more access granularities. This compiled data may further be shared with multiple accessing agents in accordance with access resolutions of the respective accessing agents.

Abstract: The present disclosure relates to systems and methods implemented on a memory controller for detecting and mitigating memory attacks (e.g., row hammer attacks). For example, a memory controller may track activations of row addresses within a memory hardware (e.g., a DRAM device) and determine whether a pattern of activations is indicative of a row hammer attack. This is determined using a counting mode for corresponding memory sub-banks. Where a likely row hammer attack is detected, the memory controller may activate a sampling mode (rather than the counting mode) for a particular sub-bank to identify which of the row addresses should be refreshed on the memory hardware. The implementations described herein provide a low computational cost alternative to heavy-handed detection mechanisms that require access to significant computing resources to accurately detect and mitigate row hammer attacks.

Abstract: A method for multiplexing access of the performance monitoring hardware in different modes includes providing a first mode at one or more guest partitions and providing a second mode at a management partition. Each of one or more guest partitions and the management partition is a virtual machine managed by a hypervisor. The first mode enables a guest partition access to the performance monitoring hardware for a corresponding partition. The second mode enables a management partition access to the performance monitoring hardware for at least one guest partition. The first mode has a first priority, and the second mode has a second priority that is lower than the first priority, such that when the first mode at a particular guest partition is enabled, the corresponding second mode at the management partition is automatically disabled.

Abstract: The present disclosure relates to systems, methods, and computer-readable media for tracking memory usage data on a memory controller system and providing a mechanism whereby one or multiple accessing agents (e.g., computing nodes, applications, virtual machines) can access memory usage data for a memory resource managed by a memory controller. Indeed, the systems described herein facilitate generation of and access to heatmaps having memory usage data thereon. The systems described herein describe features and functionality related to generating and maintaining the heatmaps as well as providing access to the heatmaps to a variety of accessing agents. This memory tracking and accessing is performed using low processing overhead while providing useful information to accessing agents in connection with memory resources managed by a memory controller.

Abstract: A computing system identifies mitigation actions in response to failures within a computer network. A service level objective is obtained by the computing system for client-resource data flows traversing the computer network between client-side and resource-side nodes. Indication of a failure event at a network location of the computer network is obtained. For each mitigation action of a set of candidate mitigation actions, an estimated impact to a distribution of the service level objective is determined for the mitigation action by applying simulated client-resource data flows to a network topology model of the computer network in combination with the mitigation action and the failure event. One or more target mitigation actions are identified by the computing system from the set of candidate mitigation actions based on a comparison of the estimated impacts of the set of candidate mitigation actions.

Abstract: The present disclosure relates to systems, methods, and computer-readable media for tracking memory usage data on a memory controller system and providing a mechanism whereby one or multiple accessing agents (e.g., computing nodes, applications, virtual machines) can access memory usage data for a memory resource managed by a memory controller. Indeed, the systems described herein facilitate generation of and access to heatmaps having memory usage data thereon. The systems described herein describe features and functionality related to generating and maintaining the heatmaps as well as providing access to the heatmaps to a variety of accessing agents. This memory tracking and accessing is performed using low processing overhead while providing useful information to accessing agents in connection with memory resources managed by a memory controller.

Abstract: A device calculates a memory oversubscription threshold for a virtual machine (VM). Based on the memory oversubscription threshold, the device determines a first memory size to be physically allocated to the VM, and a second memory size to be oversubscribed to the VM. The device configures a first virtual non-uniform memory access (NUMA) node comprising a virtual processor and a first virtual memory having the first memory size. The device allocates a first physical memory to back the first virtual memory. The device configures a second virtual NUMA node comprising a second virtual memory having the second memory size. The second virtual NUMA node is a computeless NUMA node. The device configures the VM to use the first virtual NUMA node and the second virtual NUMA node. Based on the second virtual NUMA node being computeless, the VM funnels a memory access to the first virtual memory.

Abstract: The present disclosure relates to systems and methods implemented on a memory controller for detecting and mitigating memory attacks (e.g., row hammer attacks). For example, a memory controller may engage a counting mode in which activation counts for memory sub-banks are tracked. For example, a memory controller may engage a counting mode in which activation counts for memory rows of memory sub-banks are maintained. Under certain conditions, the memory controller may transition from the counting mode to a sampling mode to mitigate potential row hammer attacks. The memory controller may consider various conditions in determining whether to continue detecting and mitigating potential row hammer attacks in the sampling mode and/or transitioning back to the counting mode. By selectively transitioning between the different operating modes, the memory controller may reduce periods of time when the memory hardware is vulnerable to attacks.

Abstract: Solutions for scheduling page migrations use latency tolerance of coupled devices, such as external peripheral devices (e.g., network adapters), to prevent buffer overflows or other negative performance. A latency tolerance of a device coupled to a virtual object, such as a virtual machine (VM) is determined. This may include the device exposing its latency tolerance using latency tolerance reporting (LTR). When a page migration for the virtual object is pending, a determination is made whether sufficient time exists to perform the page migration, based on at least the latency tolerance of the device. The page migration is performed if sufficient time exists. Otherwise, the page migration is delayed. In some examples, latency tolerances of multiple devices are considered. In some examples, multiple page migrations are performed contemporaneously, based on latency tolerances. Various options are disclosed, such as the page migration being performed by the virtual object software or the device.

Abstract: The present disclosure relates to systems and methods implemented on a memory controller for detecting and mitigating memory attacks (e.g., row hammer attacks). For example, a memory controller may track activations of row addresses within a memory hardware (e.g., a DRAM device) and determine whether a pattern of activations is indicative of a row hammer attack. This is determined using a counting mode for corresponding memory sub-banks. Where a likely row hammer attack is detected, the memory controller may activate a sampling mode (rather than the counting mode) for a particular sub-bank to identify which of the row addresses should be refreshed on the memory hardware. The implementations described herein provide a low computational cost alternative to heavy-handed detection mechanisms that require access to significant computing resources to accurately detect and mitigate row hammer attacks.

Abstract: A computing system identifies mitigation actions in response to failures within a computer network. A service level objective is obtained by the computing system for client-resource data flows traversing the computer network between client-side and resource-side nodes. Indication of a failure event at a network location of the computer network is obtained. For each mitigation action of a set of candidate mitigation actions, an estimated impact to a distribution of the service level objective is determined for the mitigation action by applying simulated client-resource data flows to a network topology model of the computer network in combination with the mitigation action and the failure event. One or more target mitigation actions are identified by the computing system from the set of candidate mitigation actions based on a comparison of the estimated impacts of the set of candidate mitigation actions.

Abstract: Methods and systems related to memory reduction in a system by oversubscribing physical memory shared among compute entities are provided. A portion of the memory includes a combination of a portion of a first physical memory of a first type and a logical pooled memory associated with the system. A logical pooled memory controller is configured to: (1) track both a status of whether a page of the logical pooled memory allocated to any of the plurality of compute entities is a known-pattern page and a relationship between logical memory addresses and physical memory addresses associated with any allocated logical pooled memory, and (2) allow the write operation to write data to any available space in the second physical memory of the first type only up to an extent of physical memory that corresponds to the portion of the logical pooled memory previously allocated to the compute entity.

Abstract: A computing system identifies mitigation actions in response to failures within a computer network. A service level objective is obtained by the computing system for client-resource data flows traversing the computer network between client-side and resource-side nodes. Indication of a failure event at a network location of the computer network is obtained. For each mitigation action of a set of candidate mitigation actions, an estimated impact to a distribution of the service level objective is determined for the mitigation action by applying simulated client-resource data flows to a network topology model of the computer network in combination with the mitigation action and the failure event. One or more target mitigation actions are identified by the computing system from the set of candidate mitigation actions based on a comparison of the estimated impacts of the set of candidate mitigation actions.

Abstract: Methods and systems related to memory reduction in a system by oversubscribing physical memory shared among compute entities are provided. A portion of the memory includes a combination of a portion of a first physical memory of a first type and a logical pooled memory associated with the system. A logical pooled memory controller is configured to: (1) track both a status of whether a page of the logical pooled memory allocated to any of the plurality of compute entities is a known-pattern page and a relationship between logical memory addresses and physical memory addresses associated with any allocated logical pooled memory, and (2) allow the write operation to write data to any available space in the second physical memory of the first type only up to an extent of physical memory that corresponds to the portion of the logical pooled memory previously allocated to the compute entity.

Abstract: The present disclosure relates to systems, methods, and computer-readable media for tracking memory usage data on a memory controller system and providing a mechanism whereby one or multiple accessing agents (e.g., computing nodes, applications, virtual machines) can access memory usage data for a memory resource managed by a memory controller. Indeed, the systems described herein facilitate generation of and access to heatmaps having memory usage data thereon. The systems described herein describe features and functionality related to generating and maintaining the heatmaps as well as providing access to the heatmaps to a variety of accessing agents. This memory tracking and accessing is performed using low processing overhead while providing useful information to accessing agents in connection with memory resources managed by a memory controller.

Abstract: Methods and systems related to memory reduction in a system by oversubscribing physical memory shared among compute entities are provided. A portion of the memory includes a combination of a portion of a first physical memory of a first type and a logical pooled memory associated with the system. A logical pooled memory controller is configured to: (1) track both a status of whether a page of the logical pooled memory allocated to any of the plurality of compute entities is a known-pattern page and a relationship between logical memory addresses and physical memory addresses associated with any allocated logical pooled memory, and (2) allow the write operation to write data to any available space in the second physical memory of the first type only up to an extent of physical memory that corresponds to the portion of the logical pooled memory previously allocated to the compute entity.

Abstract: The present disclosure relates to systems, methods, and computer-readable media for tracking memory usage data on a memory controller system and providing a mechanism whereby one or multiple accessing agents (e.g., computing nodes, applications, virtual machines) can access memory usage data for a memory resource managed by a memory controller. Indeed, the systems described herein facilitate generation of and access to heatmaps having memory usage data thereon. The systems described herein describe features and functionality related to generating and maintaining the heatmaps as well as providing access to the heatmaps to a variety of accessing agents. This memory tracking and accessing is performed using low processing overhead while providing useful information to accessing agents in connection with memory resources managed by a memory controller.

Abstract: The present disclosure relates to systems, methods, and computer-readable media for managing tracked memory usage data and performing various actions based on memory usage data tracked by a memory controller on a memory device. For example, systems described herein involve collecting and compiling data across one or more memory controllers to evaluate characteristics of the memory usage data to determine hotness metric(s) for segments of a memory resource. The systems described herein may perform a variety of segment actions based on the hotness metric(s). In addition, the systems described herein can compile the memory usage data according to one or more access granularities. This compiled data may further be shared with multiple accessing agents in accordance with access resolutions of the respective accessing agents.

Abstract: The present disclosure relates to systems, methods, and computer-readable media for tracking memory usage data on a memory controller system and providing a mechanism whereby one or multiple accessing agents (e.g., computing nodes, applications, virtual machines) can access memory usage data for a memory resource managed by a memory controller. Indeed, the systems described herein facilitate generation of and access to heatmaps having memory usage data thereon. The systems described herein describe features and functionality related to generating and maintaining the heatmaps as well as providing access to the heatmaps to a variety of accessing agents. This memory tracking and accessing is performed using low processing overhead while providing useful information to accessing agents in connection with memory resources managed by a memory controller.