摘要:
A computer-implemented method for enforcing cache coherence includes multicasting a cache request for a memory address from a requesting node without an ordering restriction over a network, collecting, by the requesting node, a combined snoop response of the cache request over a unidirectional ring embedded in the network, and enforcing cache coherence for the memory address at the requesting node, according to the combined snoop response.
摘要:
We present a triangle ordering mechanism that maintains triangle ordering of coherence messages in SMP systems. If cache A sends a multicast message to caches B and C, and if cache B sends a message to cache C after receiving and processing the multicast message from cache A, the triangle ordering mechanism ensures that cache C processes the multicast message from cache A before processing the message from cache B. The triangle ordering mechanism enables efficient snoopy cache coherence in SMP systems in which caches communicate with each other via message-passing networks. A modified version of the triangle ordering mechanism categorizes coherence messages into non-overlapping sequencing classes, and ensures triangle ordering for coherence messages in the same sequencing class. The modified triangle ordering mechanism can significantly reduce potential performance degradation due to false waiting.
摘要:
A method and system for efficient context switching are provided. An execution entity that is to be context switched out is allowed to continue executing for a predetermined period of time before being context switched out. During the predetermined period of time in which the execution entity continues to execute, the hardware or an operating system tracks and records its footprint such as the addresses and page and segment table entries and the like accessed by the continued execution. When the execution entity is being context switched back in, its page and segment table and cache states are reloaded for use in its immediate execution.
摘要:
A method for reconfiguring a cache memory is provided. The method in one aspect may include analyzing one or more characteristics of an execution entity accessing a cache memory and reconfiguring the cache based on the one or more characteristics analyzed. Examples of analyzed characteristic may include but are not limited to data structure used by the execution entity, expected reference pattern of the execution entity, type of an execution entity, heat and power consumption of an execution entity, etc. Examples of cache attributes that may be reconfigured may include but are not limited to associativity of the cache memory, amount of the cache memory available to store data, coherence granularity of the cache memory, line size of the cache memory, etc.
摘要:
With scope-based cache coherence, a cache can maintain scope information for a memory address. The scope information specifies caches in which data of the address is potentially cached, but not necessarily caches in which data of the address is actually cached. Appropriate scope information can be used as snoop filters to reduce unnecessary coherence messages and snoop operations in SMP systems. If a cache maintains scope information of an address, it can potentially avoid sending cache requests to caches outside the scope in case of a cache miss on the address. Scope information can be adjusted dynamically via a scope calibration operation to reflect changing data access patterns. A calibration prediction mechanism can be employed to predict when a scope calibration needs to be invoked.
摘要:
Systems and methods for cache replacement monitoring (CRM) are provided. The system includes a monitored cache comprising a monitored cache line set, the monitored cache line set comprising at least one cache line capable of holding data of a monitored address; and a CRM mechanism operatively associated with the monitored cache. The CRM mechanism collects CRM information for the monitored address. The method includes the steps of collecting CRM information for a monitored address in a monitored cache; and recording the CRM information for the monitored address, when at least one of (1) the monitored address is cached in the monitored cache, (2) the monitored address is replaced in the monitored cache, (3) any cache line in a cache line set corresponding to the monitored address is cached in the monitored cache, and (4) any cache line in a cache line set corresponding to the monitored address is replaced in the monitored cache.
摘要:
Memory Access Coloring provides architecture support that allows software to classify memory accesses into different congruence classes by specifying a color for each memory access operation. The color information is received and recorded by the underlying system with appropriate granularity. This allows hardware to monitor color-based cache monitoring information and provide such feedback to the software to enable various runtime optimizations. It also enables enforcement of different memory consistency models for memory regions with different colors at the same time.
摘要:
Systems and methods for cache replacement monitoring (CRM) are provided. The system includes a monitored cache comprising a monitored cache line set, the monitored cache line set comprising at least one cache line capable of holding data of a monitored address; and a CRM mechanism operatively associated with the monitored cache. The CRM mechanism collects CRM information for the monitored address. The method includes the steps of collecting CRM information for a monitored address in a monitored cache; and recording the CRM information for the monitored address, when at least one of (1) the monitored address is cached in the monitored cache, (2) the monitored address is replaced in the monitored cache, (3) any cache line in a cache line set corresponding to the monitored address is cached in the monitored cache, and (4) any cache line in a cache line set corresponding to the monitored address is replaced in the monitored cache.
摘要:
A method for performing a transaction including a transaction head and a transaction tail, includes executing the transaction head, including executing at least one memory reserve instruction to reserve a transactional memory location that are accessed in the transaction and executing the transaction tail, wherein the transaction cannot be aborted due to a data race on that transactional memory location while executing the transaction tail, wherein data of memory write operations to the transactional memory location is committed without being buffered.
摘要:
A computer readable medium is provided embodying instructions executable by a processor to perform a method for performing a transaction including a transaction head and a transaction tail, the method includes executing the transaction head, including executing at least one memory reserve instruction to reserve a transactional memory location that are accessed in the transaction and executing the transaction tail, wherein the transaction cannot be aborted due to a data race on that transactional memory location while executing the transaction tail, wherein data of memory write operations to the transactional memory location is committed without being buffered.