buzzword
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buzzword [2015/04/10 16:38] kevincha [Lecture 28 (4/8 Wed.)] |
buzzword [2015/04/13 16:08] kevincha |
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| * Debugging is also difficult (non-deterministic behavior) | * Debugging is also difficult (non-deterministic behavior) | ||
| * Dekker's algorithm | * Dekker's algorithm | ||
| - | * Inconsistency -- the two processors did NOT see the same order of | + | * Inconsistency -- the two processors did NOT see the same order of operations to memory |
| - | operations to memory | + | |
| * Sequential consistency | * Sequential consistency | ||
| * Multiple correct global orders | * Multiple correct global orders | ||
| Line 1281: | Line 1280: | ||
| * Invalidates the block on a write | * Invalidates the block on a write | ||
| * Has an exclusive state | * Has an exclusive state | ||
| + | |||
| + | ===== Lecture 29 (4/13 Mon.) ===== | ||
| + | * MSI coherent protocol | ||
| + | * The problem: unnecessary broadcasts of invalidations | ||
| + | * MESI coherent protocol | ||
| + | * Add the exclusive state: this is the only cache copy and it is a clean state to MSI | ||
| + | * Multiple invalidation tradeoffs | ||
| + | * Problem: memory can be unnecessarily updated | ||
| + | * A possible owner state (MOESI) | ||
| + | * Tradeoffs between snooping and directory based coherence protocols | ||
| + | * Slide 31 has a good summary | ||
| + | * Directory: data structures | ||
| + | * Bit vectors vs. linked lists | ||
| + | * Scalability of directories | ||
| + | * Size? Latency? Thousand of nodes? Best of both snooping and directory? | ||
buzzword.txt · Last modified: 2015/04/27 18:20 by rachata
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