Other

University of Illinois

Impact Technologies, LLC

Matthew Carl Merten

Wen-mei William Hwu

John Christopher Gyllenhaal

Andrew Raymond Trick

Christopher Neith George

A processor method and apparatus that allows for the overlapped execution of multiple iterations of a loop while allowing the compiler to include only a single copy of the loop body in the code while automatically managing which iterations are active. Since the prologue and epilogue are implicitly created and maintained within the hardware in the invention, a significant reduction in code size can be achieved compared to software-only modulo scheduling. Furthermore, loops with iteration counts less than the number of concurrent iterations present in the kernel are also automatically handled. This hardware enhanced scheme achieves the same performance as the fully-specified standard method. Furthermore, the hardware reduces the power requirement as the entire fetch unit can be deactivated for a portion of the loop's execution. The basic design of the invention involves including a plurality of buffers for storing loop instructions, each of which is associated with an instruction decoder and its respective functional unit, in the dispatch stage of a processor. Control logic is used to receive loop setup parameters and to control the selective issue of instructions from the buffers to the functional units.

Method and apparatus for modulo scheduled loop execution in a processor architecture

Disclosed is a method and apparatus for detecting and monitoring program hot spots during execution that may be implemented in hardware. A hot spot detector tracks branch instructions which are retired. Frequently executed branch instruction addresses within a particular interval are designated as hot spot candidates. A hot spot detection counter is used to track non-hot spot branches and hot spot candidate branches. When hot spot candidate branches are frequently encountered compared to non-hot spot candidate branches, the hot spot detector may notify the operating system and hot spot candidate branch addresses may be supplied to a runtime optimizing compiler and a monitor table or a hot spot monitor. The hot spot monitor may disable the hot spot detector when a program is operating in known hot spots and may enable the hot spot detector if the program has strayed from known hot spots.

Method and apparatus for instruction execution hot spot detection and monitoring in a data processing unit

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Champaign, IL, United States of America

Matthew Carl Merten