Add "Memory consistency models" subsection to "Memory orderings" section #16
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jserv
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Jun 29, 2024
jserv
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Jun 29, 2024
concurrency-primer.tex
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| y = 1; r2 = x; | ||
| \end{ccode} | ||
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| If this program satisfies sequential consistency, then for Thread 1, \monobox{x = 1} must occur before \monobox{y = 1}, and for Thread 2, \monobox{r1 = y} must occur before \monobox{r2 = x}. For the entire program, the following six execution orders are possible: |
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Did you mean I should use \cc{...} or \cpp{...} instead of \monobox{...}?
jserv
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Jun 29, 2024
concurrency-primer.tex
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| \subsubsection{Total store order (TSO)} | ||
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| Although sequential consistency is considered the "golden standard" for multi-threaded programs, its many constraints limit performance optimization. As a result, it is rarely implemented in modern processors. Instead, more relaxed memory models are used, such as the total store order (TSO) memory model adopted by the x86 architecture. One can envision the hardware roughly as follows: |
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Change the quotation mark. See https://www.maths.tcd.ie/~dwilkins/LaTeXPrimer/QuotDash.html
jserv
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Jul 1, 2024
jserv
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Jul 1, 2024
jserv
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Jul 6, 2024
jserv
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Jul 6, 2024
| \subsection{Memory consistency models} | ||
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| When a program is compiled and executed, it doesn't always follow the written order. | ||
| The system may change the sequence and optimize it to simulate line-by-line execution, as long as the final result matches the expected outcome. |
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You should address the impact from modern microprocessors and optimizing compilers.
jserv
reviewed
Jul 6, 2024
| When a program is compiled and executed, it doesn't always follow the written order. | ||
| The system may change the sequence and optimize it to simulate line-by-line execution, as long as the final result matches the expected outcome. | ||
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| This requires an agreement between the programmer and the system (hardware, compiler, etc.), ensuring that if the rules are followed, the execution will be correct. |
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Merge the statement into the previous paragraph.
jserv
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Jul 22, 2024
jserv
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Jul 22, 2024
1. split setences into separate lines 2. change the quotation marks "..." as ``...''
- Changed "doesn't" to "does not" for formal English writing - Fixed the inconsistency of quotation marks - Merged related statements into one paragraph
jserv
reviewed
Jul 23, 2024
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| The write order seen by one thread can differ from the order seen by other threads because write operations can be reordered during propagation. | ||
| However, reads and writes to the same memory address must still follow a total order. | ||
| Therefore, the following litmus test cannot result in \monobox{r1 = 1}, \monobox{r2 = 2}, but \monobox{r3 = 2}, \monobox{r4 = 1}. |
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Provide some information about running Litmus tests.
jserv
reviewed
Jul 23, 2024
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| \subsubsection{Sequential consistency (SC)} | ||
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| In the 1970s, Leslie Lamport proposed the most common memory consistency model, sequential consistency (SC), defined as follows: |
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Add some references at the end of this document.
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Any progress? |
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This pull request aims to enhance the comprehensiveness of the “Memory orderings” section of this book. Currently, the section primarily covers memory orders defined in C11/C++11 but lacks discussion on hardware assumptions regarding memory consistency. Thus I made the following changes: