Nearly symmetric multi-core processors

Abstract:

Multi-core processors are commonplace and continue to require rethinking (not only) in system software development. It is still difficult to operate several functionally identical computing cores efficiently. One misconception is to assume that functionally identical cores of a multi-core processor will behave non-functionally alike, especially at the speed at which they execute the same non-sequential program. We show that considerable deviations in the non-functional behaviour of otherwise identical cores are anything but unusual, and can be expected to vary by more than 20%. The paper documents the applied measurement methodology, discusses measurement results obtained, and addresses consequences for the coordinated operation of logically connected concurrent threads in the context of Linux.