Volume 2, Part 2: MP Coherence and Synchronization
2:507
MP Coherence and Synchronization
2
This chapter describes how to enforce an ordering of memory operations, how to
update code images, and presents examples of several simple multiprocessor
synchronization primitives on a processor based on the Itanium architecture. These
topics are relevant to anyone who writes either user- or system-level software for
multiprocessor systems based on the Itanium architecture.
The chapter begins with a brief overview of Itanium memory access instructions
intended to summarize the behaviors that are relevant to later discussions in the
chapter. Next, this chapter presents the Itanium memory ordering model and compares
it to a sequentially-consistent ordering model. It then explores versions of several
common synchronization primitives. This chapter closes by describing how to correctly
update code images to implement self-modifying code, cross-modifying code, and
paging of code using programmed I/O.
2.1
An Overview of Intel
®
Itanium
®
Memory Access
Instructions
The Itanium architecture provides load, store, and semaphore instructions to access
memory. In addition, it also provides a memory fence instruction to enforce further
ordering relationships between memory accesses. As
describes, memory operations in the Itanium architecture
come with one of four semantics: unordered, acquire, release, or fence.
on
describes how the memory ordering model uses these semantics to
indicate how memory operations can be ordered with respect to each other.
defines the four memory operation semantics.
,
present brief outlines of load and store, semaphore, and memory fence
instructions in the Itanium architecture. Refer to
Chapter 2, “Instruction Reference”
for
more information on the behavior and capabilities of these instructions.
2.1.1
Memory Ordering of Cacheable Memory References
The Itanium architecture has a relaxed memory ordering model which provides
unordered memory opcodes, explicitly ordered memory opcodes, and a fencing
operation that software can use to implement stronger ordering. Each memory
operation establishes an ordering relationship with other operations through one of four
semantics:
•
Unordered
semantics imply that the instruction is made visible in any order with
respect to other orderable instructions.
•
Acquire
semantics imply that the instruction is made visible prior to all subsequent
orderable instructions.
•
Release
semantics imply that the instruction is made visible after all prior orderable
instructions.
Содержание ITANIUM ARCHITECTURE - SOFTWARE DEVELOPERS VOLUME 3 REV 2.3
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Страница 11: ...x Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 12: ...1 1 Intel Itanium Architecture Software Developer s Manual Rev 2 3 Part I Application Architecture Guide ...
Страница 13: ...1 2 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 33: ...1 22 Volume 1 Part 1 Introduction to the Intel Itanium Architecture ...
Страница 57: ...1 46 Volume 1 Part 1 Execution Environment ...
Страница 147: ...1 136 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 149: ...1 138 Volume 1 Part 2 About the Optimization Guide ...
Страница 191: ...1 180 Volume 1 Part 2 Predication Control Flow and Instruction Stream ...
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Страница 249: ...2 1 Intel Itanium Architecture Software Developer s Manual Rev 2 3 Part I System Architecture Guide ...
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Страница 264: ...2 16 Volume 2 Part 1 Intel Itanium System Environment ...
Страница 380: ...2 132 Volume 2 Part 1 Interruptions ...
Страница 398: ...2 150 Volume 2 Part 1 Register Stack Engine ...
Страница 486: ...2 238 Volume 2 Part 1 IA 32 Interruption Vector Descriptions ...
Страница 749: ...2 501 Intel Itanium Architecture Software Developer s Manual Rev 2 3 Part II System Programmer s Guide ...
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Страница 754: ...2 506 Volume 2 Part 2 About the System Programmer s Guide ...
Страница 796: ...2 548 Volume 2 Part 2 Interruptions and Serialization ...
Страница 808: ...2 560 Volume 2 Part 2 Context Management ...
Страница 842: ...2 594 Volume 2 Part 2 Floating point System Software ...
Страница 850: ...2 602 Volume 2 Part 2 IA 32 Application Support ...
Страница 862: ...2 614 Volume 2 Part 2 External Interrupt Architecture ...
Страница 870: ...2 622 Volume 2 Part 2 Performance Monitoring Support ...
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Страница 941: ...3 42 Volume 3 Instruction Reference cmp illegal_operation_fault PR p1 0 PR p2 0 Interruptions Illegal Operation fault ...
Страница 1099: ...3 200 Volume 3 Instruction Reference padd Interruptions Illegal Operation fault ...
Страница 1191: ...3 292 Volume 3 Pseudo Code Functions Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 1295: ...3 396 Volume 3 Resource and Dependency Semantics ...
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Страница 1494: ...4 192 Volume 4 Base IA 32 Instruction Reference FWAIT Wait See entry for WAIT ...
Страница 1564: ...4 262 Volume 4 Base IA 32 Instruction Reference LES Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 1565: ...Volume 4 Base IA 32 Instruction Reference 4 263 LFS Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 1568: ...4 266 Volume 4 Base IA 32 Instruction Reference LGS Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 1583: ...Volume 4 Base IA 32 Instruction Reference 4 281 LSS Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 1647: ...Volume 4 Base IA 32 Instruction Reference 4 345 ROL ROR Rotate See entry for RCL RCR ROL ROR ...
Страница 1663: ...Volume 4 Base IA 32 Instruction Reference 4 361 SHL SHR Shift Instructions See entry for SAL SAR SHL SHR ...
Страница 1668: ...4 366 Volume 4 Base IA 32 Instruction Reference SIDT Store Interrupt Descriptor Table Register See entry for SGDT SIDT ...
Страница 1884: ...4 582 Volume 4 IA 32 SSE Instruction Reference ...
Страница 1885: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 Index ...
Страница 1886: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 1898: ...INDEX Index 12 Index for Volumes 1 2 3 and 4 ...