Cache coherent commutative operations

• Main Author: Horn, Webb H
• Other Authors: Daniel Sanchez.
• Format: Others
• Language: English
• Published: Massachusetts Institute of Technology 2016
• Subjects: Electrical Engineering and Computer Science.
• Online Access: http://hdl.handle.net/1721.1/100601

Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2015. === This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. === Cataloged from student-submitted PDF version of thesis. === Includes bibliographical references (pages 51-57). === This thesis presents Coup, a technique that reduces the cost of updates in shared memory systems. In particular, it describes a new cache coherence protocol, MEUSI, and evaluates its performance under simulation in zsim. MEUSI extends the MESI protocol to allow data to be cached in a new update-only state, reducing both block-level thrashing and on-chip network traffic under many parallel workflows. Coup permits both single-word and multi-word commutative data operations, which are implemented as x86-64 ISA extensions. To evaluate single-word instructions, this thesis presents a case study of a new reference counting scheme, and for multi-word commutative operations, this thesis describes the design of a commutative memory allocator. Coup and MEUSI confer significant benefits to the reference counting scheme and the memory allocator, both in terms of performance and ease of programming. === by Webb H. Horn. === M. Eng.