Cache Residence Prediction

A system of cache residence prediction in a computer system, comprising:

• a plurality of caches, comprising a first cache and one or more other caches;
• a memory and a memory controller operatively coupled to the memory;
• and
• a prediction mechanism operatively coupled to the first cache, the prediction mechanism predicting whether data requested by the first cache of a cache miss can be supplied by at least one of the one or more other caches, producing a prediction result, and sending the prediction result to the memory controller;
• wherein the memory controller uses the prediction result to determine if the memory is to be accessed immediately, or if the memory is not to be accessed until a corresponding cache snoop operation shows that the data requested by the first cache cannot be supplied by at least one of the one or more other caches.

A system of memory residence prediction in a computer system, comprising:

• a plurality of caches, comprising a first cache and one or more other caches;
• a memory and a memory controller operatively coupled to the memory;
• and
• a prediction mechanism predicting whether data requested by the first cache of a cache miss can be found in at least one of the one or more other caches, and producing a prediction result;
• wherein the prediction mechanism comprises a prediction table that is updated accordingly when the prediction mechanism observes a cache operation that can affect whether data requested by the first cache of a future cache miss can be found in at least one of the one or more other caches.

A system of memory residence prediction in a computer system, comprising:

• a plurality of caches, comprising a first cache and one or more other caches;
• a memory and a memory controller operatively coupled to the memory;
• a first prediction mechanism operatively coupled to the first cache, the first prediction mechanism predicting whether data requested by the first cache of a cache miss can be supplied by at least one of the one or more other caches, producing a first prediction result, and sending the first prediction result to the memory controller;
• and
• a second prediction mechanism operatively coupled to the memory, the second prediction mechanism predicting whether requested data by the first cache of a cache miss can be supplied by at least one of the one or more other caches, and producing a second prediction result;
• wherein an overall prediction result is determined by the first prediction result and the second prediction result;
• and
• wherein the memory controller uses the overall prediction result to determine if the memory is to be accessed immediately, or if the memory is not to be accessed until a corresponding cache snoop operation shows that the data requested by the first cache cannot be supplied by at least one of the one of more other caches.

A method of cache residence prediction in a computer system, comprising the steps of:

• receiving a cache miss of a first address by a first cache;
• predicting that data requested of the cache miss by the first cache can be supplied by one or more other caches, if the first address matches an address tag of a cache line in the first cache and the cache line is in an invalid cache;
• and
• producing a prediction result and sending the prediction result to a component that can use the prediction result for some appropriate optimization.

A machine-readable medium having instructions stored thereon for cache residence prediction in a computer system, comprising the steps of:

• receiving a cache miss of a first address by a first cache;
• predicting that data requested of the cache miss by the first cache can be supplied by one or more other caches, if the first address matches an address tag of a cache line in the first cache and the cache line is in an invalid cache;
• and
• producing a prediction result and sending the prediction result to a component that can use the prediction result for some appropriate optimization.