摘要:
Mechanisms are provided for processing an instruction in a processor of a data processing system. The mechanisms operate to receive, in a processor of the data processing system, an instruction, the instruction including power/performance tradeoff information associated with the instruction. The mechanisms further operate to determine power/performance tradeoff priorities or criteria, specifying whether power conservation or performance is prioritized with regard to execution of the instruction, based on the power/performance tradeoff information. Moreover, the mechanisms process the instruction in accordance with the power/performance tradeoff priorities or criteria identified based on the power/performance tradeoff information of the instruction.
摘要:
A technique for sharing a fabric to facilitate off-chip communication for on-chip units includes dynamically assigning a first unit that implements a first communication protocol to a first portion of the fabric when private fabrics are indicated for the on-chip units. The technique also includes dynamically assigning a second unit that implements a second communication protocol to a second portion of the fabric when the private fabrics are indicated for the on-chip units. In this case, the first and second units are integrated in a same chip and the first and second protocols are different. The technique further includes dynamically assigning, based on off-chip traffic requirements of the first and second units, the first unit or the second unit to the first and second portions of the fabric when the private fabrics are not indicated for the on-chip units.
摘要:
A mechanism is provided in a virtual machine monitor for fine grained cache allocation in a shared cache. The mechanism partitions a cache tag into a most significant bit (MSB) portion and a least significant bit (LSB) portion. The MSB portion of the tags is shared among the cache lines in a set. The LSB portion of the tags is private, one per cache line. The mechanism allows software to set the MSB portion of tags in a cache to allocate sets of cache lines. The cache controller determines whether a cache line is locked based on the MSB portion of the tag.
摘要:
A method for compiler assisted victim cache bypassing including: identifying a cache line as a candidate for victim cache bypassing; conveying a bypassing-the-victim-cache information to a hardware; and checking a state of the cache line to determine a modified state of the cache line, wherein the cache line is identified for cache bypassing if the cache line that has no reuse within a loop or loop nest and there is no immediate loop reuse or there is a substantial across loop reuse distance so that it will be replaced from both main and victim cache before being reused.
摘要:
A mechanism is provided within a 3D stacked memory organization to spread or stripe cache lines across multiple layers. In an example organization, a 128B cache line takes eight cycles on a 16B-wide bus. Each layer may provide 32B. The first layer uses the first two of the eight transfer cycles to send the first 32B. The next layer sends the next 32B using the next two cycles of the eight transfer cycles, and so forth. The mechanism provides a uniform memory access.
摘要:
A mechanism is provided in a virtual machine monitor for fine grained cache allocation in a shared cache. The mechanism partitions a cache tag into a most significant bit (MSB) portion and a least significant bit (LSB) portion. The MSB portion of the tags is shared among the cache lines in a set. The LSB portion of the tags is private, one per cache line. The mechanism allows software to set the MSB portion of tags in a cache to allocate sets of cache lines. The cache controller determines whether a cache line is locked based on the MSB portion of the tag.
摘要:
A technique for performing stream detection and prefetching within a cache memory simplifies stream detection and prefetching. A bit in a cache directory or cache entry indicates that a cache line has not been accessed since being prefetched and another bit indicates the direction of a stream associated with the cache line. A next cache line is prefetched when a previously prefetched cache line is accessed, so that the cache always attempts to prefetch one cache line ahead of accesses, in the direction of a detected stream. Stream detection is performed in response to load misses tracked in the load miss queue (LMQ). The LMQ stores an offset indicating a first miss at the offset within a cache line. A next miss to the line sets a direction bit based on the difference between the first and second offsets and causes prefetch of the next line for the stream.
摘要:
Mechanisms for accessing a set associative cache of a data processing system are provided. A set of cache lines, in the set associative cache, associated with an address of a request are identified. Based on a determined mode of operation for the set, the following may be performed: determining if a cache hit occurs in a preferred cache line without accessing other cache lines in the set of cache lines; retrieving data from the preferred cache line without accessing the other cache lines in the set of cache lines, if it is determined that there is a cache hit in the preferred cache line; and accessing each of the other cache lines in the set of cache lines to determine if there is a cache hit in any of these other cache lines only in response to there being a cache miss in the preferred cache line(s).
摘要:
A technique for performing stream detection and prefetching within a cache memory simplifies stream detection and prefetching. A bit in a cache directory or cache entry indicates that a cache line has not been accessed since being prefetched and another bit indicates the direction of a stream associated with the cache line. A next cache line is prefetched when a previously prefetched cache line is accessed, so that the cache always attempts to prefetch one cache line ahead of accesses, in the direction of a detected stream. Stream detection is performed in response to load misses tracked in the load miss queue (LMQ). The LMQ stores an offset indicating a first miss at the offset within a cache line. A next miss to the line sets a direction bit based on the difference between the first and second offsets and causes prefetch of the next line for the stream.
摘要:
A technique for performing stream detection and prefetching within a cache memory simplifies stream detection and prefetching. A bit in a cache directory or cache entry indicates that a cache line has not been accessed since being prefetched and another bit indicates the direction of a stream associated with the cache line. A next cache line is prefetched when a previously prefetched cache line is accessed, so that the cache always attempts to prefetch one cache line ahead of accesses, in the direction of a detected stream. Stream detection is performed in response to load misses tracked in the load miss queue (LMQ). The LMQ stores an offset indicating a first miss at the offset within a cache line. A next miss to the line sets a direction bit based on the difference between the first and second offsets and causes prefetch of the next line for the stream.