International Business Machines Corporation

Gisle Dankel

Gavin Barraclough

Kit Man Wan

Geraint M North

Miles Philip Howson

Matthew Evans

Disclosed are a method and apparatus for protecting memory consistency in a multiprocessor computing system, relating to program code conversion such as dynamic binary translation. The exemplary multiprocessor computing system provides memory and multiple processors, and a set of controller/translator units TX, TX, TXarranged to convert respective application programs into program threads T, T, etc., which are executed by the processors. Each controller/translator unit sets a first mode where a single thread Texecutes on a single processor P, orders a second mode for two or more threads T, Tthat are forced to execute one at a time on a single processor Psuch as by setting affinity with that processor, and orders a third mode to selectively apply active memory consistency protection in relation to accesses to explicit or implicit shared memory while allowing the multiple threads T, T, T, Tto execute on the multiple processors.

Multiprocessor computing system with multi-mode memory consistency protection

A method and apparatus to protect memory consistency in a multiprocessor computing system are described, in particular relating to program code conversion such as dynamic binary translation. The exemplary system provides a memory, processors and a controller/translator unit (CTU) arranged to convert subject code into at least first and second target code portions executable on the processors. The CTU comprises an address space allocation unit to provide virtual address space regions and direct the target code portions to access the memory therethough; a shared memory detection unit to detect a request to access a shared memory area, accessible by both target code portions, and to identify at least one group of instructions in the first target code portion which access the shared memory area; and a memory protection unit to selectively apply memory consistency protection in relation to accesses to the shared memory area by the identified group of instructions.

Memory consistency protection in a multiprocessor computing system

A translator apparatus is provided with both program code interpreting and translating functionality, where subject program code is interpreted rather than being translated in those situations where interpretation of the subject program code is determined to be more beneficial. The translator applies an interpreting algorithm to determine whether a basic block of subject program code should be interpreted or translated. A particular subject of instructions supported by the interpreter functionality is initially selected from an entire instruction set for the subject program code. A basic block will be interpreted 1) if all of the instructions within a basic block are determined to be within the subset of instructions supported by the interpreter functionality, and 2) if an execution count of the basic block is below a translation threshold. If either of these two conditions are not satisfied, then the basic block is translated by the translator

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Salford, United Kingdom

Gisle Dankel