Processor prefetch throttling based on short streams

A method comprising:

• maintaining, by a prefetch circuit of a processor, a prefetch history array comprising a plurality of entries, the plurality of entries comprising a plurality of sublength values, each entry comprising a sublength value, wherein each sublength value is a numeric value indicating a frequency that a stride is repeated for a corresponding prefetch address;
• for each entry of the plurality of entries, the prefetch circuit adjusting the sublength value based on whether loads associated with the entry have stride matches;
• the prefetch circuit comparing each of the plurality of sublength values to a short stream threshold;
• the prefetch circuit incrementing a short stream counter for each of the plurality of sublength values that has not exceeded the short stream threshold, wherein the short stream counter is distinct from the plurality of entries;
• the prefetch circuit decrementing the short stream counter for each of the plurality of sublength values that has exceeded the short stream threshold;
• the prefetch circuit determining whether the short stream counter has exceeded a throttling threshold;
• and
• the prefetch circuit increasing throttling of a prefetch level of all prefetches by the prefetch circuit in response to a determination that the short stream counter has exceeded the throttling threshold.

A system comprising:

• a processor including a prefetch circuit to:
• maintain a prefetch history array comprising a plurality of entries, the plurality of entries comprising a plurality of sublength values, each entry comprising a sublength value, wherein each sublength value is a numeric value indicating a frequency that a stride is repeated for a corresponding prefetch address;
• adjust the sublength values of the plurality of entries based on stride matches;
• compare each of the plurality of sublength values to a short stream threshold;
• increment a short stream counter for each of the plurality of sublength values that has not exceeded the short stream threshold, wherein the short stream counter is distinct from the plurality of entries in the prefetch history array;
• decrement the short stream counter for each of the plurality of sublength values that has exceeded the short stream threshold;
• determine whether the short stream counter has exceeded a throttling threshold;
• and
• throttle a prefetch level of all prefetches by the prefetch circuit in response to a determination that the short stream counter has exceeded the throttling threshold;
• and
• an external memory coupled to the processor.