US 6,324,616 B2 · Dynamically inhibiting competing resource requesters in favor of above threshold usage requester to reduce response delay

Abstract

A method of limiting, in a digital processor, low-priority utilization of a resource in favor of high-priority utilization of the resource comprises determining a value predictive of high-priority utilization of the resource. Low-priority utilization of the resource is inhibited if the determined predictive value is greater than a threshold. On the other hand, if the predictive value is less than or equal to the threshold, then low-priority utilization of the resource is allowed. In a preferred embodiment, the predictive value is derived by counting the number of actual high-priority utilizations of the resource out of the last N opportunities in which the resource could have been utilized for a high-priority need. Preferably, recent utilizations are given more weight than others. In a preferred embodiment, the resource comprises one of main memory, instruction cache memory, or data cache memory. High-priority utilization comprises high-priority access to memory and low-priority utilization comprises memory prefetching. Low priority utilizations are throttled when the threshold is exceeded. Counting and comparing are done with a shift register, counting logic, and a comparator; or with a counter and a comparator; or with two shift registers in which case no comparator is needed.

Claims25

Dependent claims

An apparatus for dynamically throttling a hardware prefetcher in a computer system with fetching hardware and memory, comprising:

a counter having a value, wherein the counter value is incremented for each memory high-priority request opportunity in which a memory high-priority request is made, and wherein the counter value is decremented for each memory high-priority request opportunity in which no memory request is made;
and
a comparator coupled to the counter and comparing the counter value with a predetermined threshold, such that if the value exceeds the threshold, indicating a high number of high-priority requests, the hardware prefetcher is disabled, and if the value does not exceed the threshold, the hardware prefetcher is not throttled.

Dependencies are inferred from the claim text.

Dynamically inhibiting competing resource requesters in favor of above threshold usage requester to reduce response delay

Life of this patent

Dynamically inhibiting competing resource requesters in favor of above threshold usage requester to reduce response delay

Life of this patent

Abstract

Claims25