Intel Corporation

Marvell International Limited

David E Miner

Sujat Jamil

R Frank O'Bleness

Steven J Tu

Samantha J Edirisooriya

Hang T Nguyen

Tom Marko Hameenanttila

Joseph Anthony Delgross

Jeffrey Kehl

Kim Richard Schuttenberg

Richard F Bryant

Scott W Murray

Frank O'Bleness

Gregory W Tse

Russell J Robideau

Adi Habusha

Mark Norman Fullerton

A method can include executing a store instruction that instructs storing of data at an address and, in response to the store instruction, inserting a preloading instruction after the store instruction but before a dependent load instruction to the address. Executing the store instruction can include invalidating a data entry of a cache array at an address of the cache array corresponding to the address and writing the data to a backing memory at an address of the backing memory corresponding to the address. The preloading instruction can cause filling the data entry of the cache array, at the address of the cache array corresponding to the address, with the data from the backing memory at the address of the backing memory corresponding to the address and validating the data entry of the cache array.

Method and apparatus for use of a preload instruction to improve efficiency of cache

A system and method of tracking multiple non-identification tagged requests in a system with multiple responders are disclosed. In one embodiment, an electronic memory system comprises a memory configured to implement a plurality of response queues, wherein one response queue is associated with one responder from a plurality of responders, and wherein a responder is a device capable of resolving the memory request. A tracking module is configured to assign identification information to a memory request that is received and store the identification information in one or more queues of the plurality of response queues; and to transmit the memory request to each responder that is associated with the one or more queues. A response module is configured to associate the identification information in the one or more queues with a response upon receiving the response from the one or more responders.

Method and apparatus for associating requests and responses with identification information

An apparatus including a snoop filter decoupled from a cache and an associated method for snoop filtering are disclosed. The snoop filter is decoupled from the cache such that the cache changes states of lines in the cache from a first state that is a clean state, such as an exclusive (E) state, to a second state that is not a clean state, such as a modified (M) state, without the snoop filter's knowledge. The snoop filter buffers addresses of replaced lines that are unknown to be clean until a write-back associated with the replacement lines occurs, or until actual states of the replaced lines are determined by the snoop filter generating a snoop. A multi-level cache system in which a reallocation or replacement policy is biased to favor replacing certain lines such as inclusive lines, non-temporal lines or prefetched lines that have not been accessed, is also disclosed.

Method and apparatus having a snoop filter decoupled from an associated cache and a buffer for replacement line addresses

Devices, systems, methods, and other embodiments associated with a cache memory are described. In one embodiment, a cache tag array includes tag banks. The cache memory further includes a bank selector configured to receive an address and to apply a hash function that maps the address to one of the tag banks.

Cache memory bank selection

Aspects of the disclosure provide methods for cache efficiency. A method for cache efficiency can include storing data in a buffer entry in association with a cache array in response to a first store instruction that hits the cache array before the first store instruction is committed. Further, when a dependent load instruction is subsequent to the first store instruction, the method can include providing the data from the buffer entry in response to the first dependent load instruction. When a second store instruction overlaps an address of the first store instruction, the method can include coalescing data of the second store instruction in the buffer entry before the second store instruction is committed. When the second store instruction is followed by a second dependent load instruction, the method can include providing the coalesced data from the buffer entry in response to the second dependent load instruction.

Method and apparatus for improving cache efficiency

A programmable cache and cache access protocol that can be dynamically optimized with respect to either power consumption or performance based on a monitored performance of the cache. A monitoring unit monitors cache misses, load use penalty, and/or other performance parameter, and compares the monitored values against a set of one or more predetermined thresholds. Based on the comparison results, a cache controller configures the programmable cache to operate in a parallel mode, to increase cache performance at the cost of greater power consumption, or in a serial mode, to conserve power at the cost of unnecessary performance. A banked cache memory that supports aligned and unaligned instruction fetches using a banked access strategy, and a cache access controller that includes a prefetch capability are also described.

Programmable cache access protocol to optimize power consumption and performance

A system and method of tracking multiple non-identification tagged requests in a system with multiple responders using one or more tracking queues. In some embodiments, the system and method may be implemented in a snoop filter covering multiple caches. In some embodiments, a data-less bus query may be used to update the status of a requested line.

Set-associative caches having corresponding methods and computer programs comprise: a data cache to provide a plurality of cache lines based on a set index of a virtual address, wherein each of the cache lines corresponds to one of a plurality of ways of the set-associative cache; a translation lookaside buffer to provide one of a plurality of way selections based on the set index of the virtual address and a virtual tag of the virtual address, wherein each of the way selections corresponds to one of the ways of the set-associative cache; and a way multiplexer to select one of the cache lines provided by the data cache based on the one of the plurality of way selections.

Way-selecting translation lookaside buffer

Non-processor agents, such as bus agents, may directly access processor caches. A coherency protocol ensures that cache coherency is maintained.

Implementing direct access caches in coherent multiprocessors

Method and apparatus for data-less bus query

A processor includes a first level of cache memory and a first set of instructions configured to implement a first cache coherency protocol. The processor also includes a second set of instructions configured to implement a second cache coherency protocol and a cache coherency protocol selector having at least two choice-states. The processor further includes a cache coherency implementer configured to implement the first cache coherency protocol or the second cache coherency with respect to the first level of cache memory based on a selected choice-state of the cache coherency protocol selector.

Method and apparatus for hardware-configurable multi-policy coherence protocol

A semiconductor chip is described having a plurality of processing cores. The semiconductor chip also includes a plurality of test controllers. Each test controller is associated with a different one of the processing cores. The semiconductor chip also includes a test port having a first serial input and a first serial output. The first serial input is to receive serial test input data provided to the semiconductor chip. The first serial output is to provide serial output data provided by the semiconductor chip. The semiconductor chip further includes switch circuitry coupled to the test port and the plurality of test controllers. The switch circuitry is to route the serial test input data to one of the plurality of test controllers and to route the serial output data from one of the plurality of test controllers to the first serial output. The semiconductor chip further includes a configuration register coupled to the switch circuitry to establish the switch circuitry's routing configuration.

Test access port

A method and apparatus for power optimized replay. In one embodiment, the method includes the issuance of an instruction selected from a queue. Once issued, the instruction may be enqueued within a recirculation queue if completion of the instruction is blocked by a detected blocking condition. Once enqueued, instructions contained within the recirculation queue may be reissued once a blocking condition of an instruction within the recirculation queue is satisfied. Accordingly, a power optimized replay scheme as described herein optimizes power while retaining the advantages provided by selectively replaying of blocked instructions to improve power efficiency.

Power optimized replay of blocked operations in a pipilined architecture

A bus control system includes N bus agents each having a corresponding bus request delay and M bus agents each having a corresponding bus request delay. A controller determines the bus request delays of the N bus agents and the M bus agents and grants concurrent ownership of a bus to each of the N bus agents and non-concurrent ownership of the bus to each of the M bus agents based on the determination. M and N are integers greater than 1.

Growing community of inventors

Chandler, AZ, United States of America

David E Miner