A coherent data processing system includes a system fabric communicatively coupling a plurality of coherence participants and fabric control logic. The fabric control logic quantifies congestion on the system fabric based on coherence messages associated with commands issued on the system fabric. Based on the congestion on the system fabric, the fabric control logic determines a rate of request issuance applicable to a set of coherence participants among the plurality of coherence participants. The fabric control logic issues at least one rate command to set a rate of request issuance to the system fabric of the set of coherence participants.

The present disclosure provides a method and a system of verifying access by a multi-core interconnect to an L2 cache in order to solve problems of delays and difficulties in locating errors and generating check expectation results. A consistency transmission monitoring circuitry detects, in real time, interactions among a multi-core interconnects system, all single-core processors, an L2 cache and a primary memory, and sends collected transmission information to an L2 cache expectation generator and a check circuitry. The L2 cache expectation generator obtains information from a global memory precise control circuitry according to a multi-core consistency protocol and generates an expected result. The check circuitry is responsible for comparing the expected result with an actual result, thus implementing determination of multi-core interconnect's access accuracy to the L2 cache without delay.

A multicore processing environment (MCPE) is disclosed. In embodiments, the MCPE includes multiple processing cores hosting multiple user applications configured for simultaneous execution. The cores and user applications share system resources including main memory and input/output (I/O) domains, each I/O domain including multiple I/O devices capable of requesting inbound access to main memory through an I/O memory management unit (IOMMU). For example, the IOMMU cache associates unique cache tags to each I/O device based on device identifiers or settings determined by the system registers, caching the configuration data for each I/O device under the appropriate cache tag. When each I/O device requests main memory access, the IOMMU cache refers to the appropriate configuration data under the corresponding unique cache tag. This prevents contention in the IOMMU cache caused by one device evicting the cache entry of another, minimizing interference channels by reducing the need for main memory access.

An apparatus includes a CPU core, a first cache subsystem coupled to the CPU core, and a second memory coupled to the cache subsystem. The first cache subsystem includes a configuration register, a first memory, and a controller. The controller is configured to: receive a request directed to an address in the second memory and, in response to the configuration register having a first value, operate in a non-caching mode. In the non-caching mode, the controller is configured to provide the request to the second memory without caching data returned by the request in the first memory. In response to the configuration register having a second value, the controller is configured to operate in a caching mode. In the caching mode the controller is configured to provide the request to the second memory and cache data returned by the request in the first memory.

A computer-implemented method includes identifying two or more memory locations and referencing, by a memory access request, the two or more memory locations. The memory access request is a single action pursuant to a memory protocol. The computer-implemented method further includes sending the memory access request from one or more processors to a node and fetching, by the node, data content from each of the two or more memory locations. The computer-implemented method further includes packaging, by the node, the data content from each of the two or more memory locations into a memory package, and returning the memory package from the node to the one or more processors. A corresponding computer program product and computer system are also disclosed.

A method and a system detects a cache line as a potential or confirmed hot cache line based on receiving an intervention of a processor associated with a fetch of the cache line. The method and system include suppressing an action of operations associated with the hot cache line. A related method and system detect an intervention and, in response, communicates an intervention notification to another processor. An alternative method and system detect a hot data object associated with an intervention event of an application. The method and system can suppress actions of operations associated with the hot data object. An alternative method and system can detect and communicate an intervention associated with a data object.

A device connected to a host processor via a bus includes: an accelerator circuit configured to operate based on a message received from the host processor; and a controller configured to control an access to a memory connected to the device, wherein the controller is further configured to, in response to a read request received from the accelerator circuit, provide a first message requesting resolution of coherence to the host processor and prefetch first data from the memory.

Disclosed embodiments relate to a security firewall having a security hierarchy including: secure master (SM); secure guest (SG); and non-secure (NS). There is one secure master and n secure guests. The firewall includes one secure region for secure master and one secure region for secure guests. The SM region only allows access from the secure master and the SG region allows accesses from any secure transaction. Finally, the non-secure region can be implemented two ways. In a first option, non-secure regions may be accessed only upon non-secure transactions. In a second option, non-secure regions may be accessed any processing core. In this second option, the access is downgraded to a non-secure access if the security identity is secure master or secure guest. If the two security levels are not needed the secure master can unlock the SM region to allow any secure guest access to the SM region.

Disclosed embodiments relate to a security firewall having a security hierarchy including: secure master (SM); secure guest (SG); and non-secure (NS). There is one secure master and n secure guests. The firewall includes one secure region for secure master and one secure region for secure guests. The SM region only allows access from the secure master and the SG region allows accesses from any secure transaction. Finally, the non-secure region can be implemented two ways. In a first option, non-secure regions may be accessed only upon non-secure transactions. In a second option, non-secure regions may be accessed any processing core. In this second option, the access is downgraded to a non-secure access if the security identity is secure master or secure guest. If the two security levels are not needed the secure master can unlock the SM region to allow any secure guest access to the SM region.

Disclosed herein are methods, systems, and processes to provide coherency across disjoint caches in clustered environments. It is determined whether a data object is owned by an owner node, where the owner node is one of multiple nodes of a cluster. If the owner node for the data object is identified by the determining, a request is sent to the owner node for the data object. However, if the owner node for the data object is not identified by the determining, selects a node in the cluster is selected as the owner node, and the request for the data object is sent to the owner node.