International Business Machines Corporation

Luis Alfonso Lastras Montaño

Peter Anthony Franaszek

R Brett Tremaine

Steven R Kunkel

Aaron Christoph Sawdey

A system includes a processor, a memory, a cache, program software, and a marker management engine. The software includes at least one marker. Each marker is a computer instruction and marks distinct computer code sections in the software. The engine (a) determines whether one of the at least one marker is executed during the execution of the program software, (b) monitors data accesses by the at least one processor to the at least one cache and the main memory, (c) stores at least one of the monitored data accesses in a pre-defined location in the main memory, and (d) optimizes only the computer code section indicated by the determined marker of the program software executed by the at least one processor based on the stored data accesses.

Learning and cache management in software defined contexts

A method of optimizing a computer program includes executing a program including a hint defined as a variable in program and providing within the program, and a marker instruction that receives the hint as a parameter. The marker instruction marks a section of the computer program for a subsequent optimization. During the execution of the computer program, and in response to the marker instruction being executed, a hardware engine monitors data accesses associated with execution of instructions in the marked section and stores the data accesses in the storage of the hint. A subsequent execution of the marked section of the computer program is optimized using the data stored in the storage of the hint.

We present a 'directory extension' (hereinafter 'DX') to aid in prefetching between proximate levels in a cache hierarchy. The DX may maintain (1) a list of pages which contains recently ejected lines from a given level in the cache hierarchy, and (2) for each page in this list, the identity of a set of ejected lines, provided these lines are prefetchable from, for example, the next level of the cache hierarchy. Given a cache fault to a line within a page in this list, other lines from this page may then be prefetched without the substantial overhead to directory lookup which would otherwise be required.

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Cortland Manor, NY, United States of America

Luis Alfonso Lastras Montaño