An operating method of a system-on-chip includes outputting a prefetch command in response to an update of mapping information on a first read target address, the update occurring in a first translation lookaside buffer storing first mapping information of a second address with respect to a first address, and storing, in response to the prefetch command, in a second translation lookaside buffer, second mapping information of a third address with respect to at least some second addresses of an address block including a second read target address.

A computer system includes a physical memory having a first page table and a second page table, and an address translation module. The first page table includes primary page table entries, where each page table entry among the primary page table entries is configured to store a mapping of a virtual memory address to a physical memory address and auxiliary information. The second page table includes secondary page table entries each storing at least one further auxiliary information, where each secondary page table entry corresponds to a primary page table entry in the first page table. The address translation module is configured to, in response to receiving a request from a processor, walk through the first page table to identify a primary page table entry and consecutively identify a location of a corresponding secondary page table entry based on a location of the primary page table entry.

Systems and methods are provided to perform fine-grained memory accesses using a memory controller. The memory controller can access elements stored in memory across multiple dimensions of a matrix. The memory controller can perform accesses to non-contiguous memory locations by skipping zero or more elements across any dimension of the matrix.

Techniques are disclosed relating to caching for address translation. In some embodiments, address translation circuitry is configured to process requests to translate addresses in a first address space to addresses in a second address space. The translation circuitry may include cache circuitry configured to store translation information, arbitration circuitry configured to arbitrate among ready requests for access to entries of the cache, and hazard circuitry. The hazard circuitry may assign a first request to an ready status the arbitration circuitry based on detection of an absence of hazards for a first address of the first request and add a second request to a queue of requests for the arbitration circuitry based on detection of a hazard for a second address of the second request. Independent arbitration for requests without hazards may improve performance in various aspects, relative to traditional techniques.

Aspects relate to Input/Output (IO) Memory Management Units (MMUs) that include hardware structures for implementing virtualization. Some implementations allow guests to setup and maintain device IO tables within memory regions to which those guests have been given permissions by a hypervisor. Some implementations provide hardware page table walking capability within the IOMMU, while other implementations provide static tables. Such static tables may be maintained by a hypervisor on behalf of guests. Some implementations reduce a frequency of interrupts or invocation of hypervisor by allowing transactions to be setup by guests without hypervisor involvement within their assigned device IO regions. Devices may communicate with IOMMU to setup the requested memory transaction, and completion thereof may be signaled to the guest without hypervisor involvement. Various other aspects will be evident from the disclosure.

Tracking memory block access frequency in processor-based devices is disclosed herein. In one exemplary embodiment, a processor-based device provides a processing element (PE) that is configured to include an access count table for tracking accesses to memory blocks. The access count table is a packed table that comprises a plurality of access count values, each of which corresponds to a memory block of a plurality of memory blocks. Upon detecting a memory access operation (i.e., data-side operations such as memory load operations, memory store operations, atomic increment operations , set operations, and the like, or instruction-side operations such as code fetch operations) directed to a given memory block, the PE increments an access count value corresponding to the memory block. The access count value then can be accessed (e.g., by a process executing on the PE), and used to determine an access frequency for the memory block.

Performance optimization is achieved by clarifying cache usage characteristics of each application from usage conditions of physical resources (caches) in real time and automatically controlling the cache usage amount of each application. Thus, a system includes a main memory to and from which data is written and read, a level 3 cache memory which can be accessed faster than the main memory, a CPU core configured to execute processing by performing write and read to and from the memory and the cache, a usage amount measurement unit configured to measure a usage condition of a cache of each virtual machine (13a to 13c) executed by the CPU core, an allocation amount calculation unit configured to calculate cache capacity to be allocated to each virtual machine (13a to 13c) from the usage condition, and a control unit configured to allocate the cache capacity to each virtual machine (13a to 13c).

A system comprises a processor including a CPU core, first and second memory caches, and a memory controller subsystem. The memory controller subsystem speculatively determines a hit or miss condition of a virtual address in the first memory cache and speculatively translates the virtual address to a physical address. Associated with the hit or miss condition and the physical address, the memory controller subsystem configures a status to a valid state. Responsive to receipt of a first indication from the CPU core that no program instructions associated with the virtual address are needed, the memory controller subsystem reconfigures the status to an invalid state and, responsive to receipt of a second indication from the CPU core that a program instruction associated with the virtual address is needed, the memory controller subsystem reconfigures the status back to a valid state.

A device including: a processor executing a program; a first cache memory; a second cache memory belonging to a memory hierarchy lower than that of the first cache memory; a determination unit that determines, based on first information indicating a virtual address of information accessed in the second cache memory when the program is executed, second information indicating a virtual address of target information to be prefetched; and a prefetch unit that prefetches the target information and stores the prefetched target information in the second cache memory, wherein the second cache memory includes a conversion unit that converts, by using correspondence information indicating a correspondence relationship between the physical address of the target information and the virtual address of the target information, the second information into third information indicating a physical address of the target information, and the prefetch unit prefetches the target information using the third information.

A system, method and apparatus to facilitate data exchange via pointers. For example, in a computing system having a first processor and a second processor that is separate and independent from the first processor, the first processor can run a program configured to use a pointer identifying a virtual memory address having an ID of an object and an offset within the object. The first processor can use the virtual memory address to store data at a memory location in the computing system and/or identify a routine at the memory location for execution by the second processor. After the pointer is communicated from the first processor to the second processor, the second processor can access the same memory location identified by the virtual memory address. The second processor may operate on the data stored at the memory location or load the routine from the memory location for execution.