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buzzword [2015/04/03 18:20]
rachata
buzzword [2015/04/06 19:11]
kevincha [Lecture 27 (4/6 Mon.)]
Line 1194: Line 1194:
       * Based on the characteristics       * Based on the characteristics
         * Frequently accessed data that need lower write latency in DRAM         * Frequently accessed data that need lower write latency in DRAM
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-    ​ 
   ​   ​
  
 +===== Lecture 27 (4/6 Mon.) =====
 +  * Flynn'​s taxonomy
 +  * Parallelism
 +    * Reduces power consumption (P ~ CV^2F)
 +    * Better cost efficiency and easier to scale
 +    * Improves dependability (in case the other core is faulty
 +  * Different types of parallelism
 +    * Instruction level parallelism
 +    * Data level parallelism
 +    * Task level parallelism
 +  * Task level parallelism
 +    * Partition a single, potentially big, task into multiple parallel sub-task
 +      * Can be done explicitly (parallel programming by the programmer)
 +      * Or implicitly (hardware partitions a single thread speculatively)
 +    * Or, run multiple independent tasks (still improves throughput, but the speedup of any single tasks is not better, also simpler to implement)
 +  * Loosely coupled multiprocessor
 +    * No shared global address space
 +      * Message passing to communicate between different sources
 +    * Simple to manage memory
 +  * Tightly coupled multiprocessor
 +    * Shared global address space
 +    * Need to ensure consistency of data
 +    * Programming issues
 +  * Hardware-based multithreading
 +    * Coarse grained
 +    * Find grained
 +    * Simultaneous:​ Dispatch instruction from multiple threads at the same time
 +  * Parallel speedup
 +    * Superlinear speedup
 +  * Utilization,​ Redundancy, Efficiency
 +  * Amdahl'​s law
 +    * Maximum speedup
 +    * Parallel portion is not perfect
 +      * Serial bottleneck
 +      * Synchronization cost
 +      * Load balance
 +        * Some threads has more work, requires more time to hit the sync. point
 +  * Critical sections
 +    * Enforce mutually exclusive access to shared data
 +  * Issues in parallel programming
 +    * Correctness
 +    * Synchronization
 +    * Consistency
buzzword.txt ยท Last modified: 2015/04/27 18:20 by rachata