{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

ece475-l22 - ECE 475/CS 416 Computer Architecture Relaxed...

Info icon This preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
ECE 475/CS 416 Computer Architecture - Relaxed Memory Model Edward Suh C omputer S ystems L aboratory [email protected] ECE 475/CS 416 — Computer Architecture, Fall 2007 Prof. Suh Announcements Lab3 is graded Re-grade request till Nov 29th No class on Thursday
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
ECE 475/CS 416 — Computer Architecture, Fall 2007 Prof. Suh Review Sequential consistency Memory ordering Cache coherence Cache coherence protocol Snoopy Directory-based ECE 475/CS 416 — Computer Architecture, Fall 2007 Prof. Suh Sequential Consistency In-order instruction execution Atomic loads and stores SC is easy to understand but architects and compiler writers want to violate it for performance Processor 1 Processor 2 Store ( a) , 10; L: Load r1, ( flag ); Store ( flag ), 1; if r 1 == 0 goto L; Load r2, ( a ); initially flag = 0
Image of page 2
ECE 475/CS 416 — Computer Architecture, Fall 2007 Prof. Suh Memory Model Issues Architectural optimizations that are correct for uniprocessors, often violate sequential consistency and result in a new memory model for multiprocessors ECE 475/CS 416 — Computer Architecture, Fall 2007 Prof. Suh Committed Store Buffers CPU Cache Main Memory CPU Cache CPU can continue execution while earlier committed stores are still propagating through memory system Processor can commit other instructions (including loads and stores) while first store is committing to memory Committed store buffer can be combined with speculative store buffer in an out-of-order CPU Local loads can bypass values from buffered stores to same address
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern