Sectioned Partitioning (Iteration #1) p r 0 g r a m m n g m a i e y p a r a e l p r o r Thread 0 Thread 1 Thread 2 Thread 3 0 0 0 3 0 0 0 a-d e-h i-l m-p q-t U-X y-Z 电子神越女学 0
6 Sectioned Partitioning (Iteration #1)
Sectioned Partitioning (Iteration #2) 0 r 0 g r a m m n m a i e p a r e p r 0 e Thread 0 Thread 1 Thread 2 Thread 3 2 0 0 A 1 0 0 a-d e-h i m-p q-t U-X y-2 电子神越女学 O
7 Sectioned Partitioning (Iteration #2) 7
Input Partitioning Affects Memory Access Efficiency Sectioned partitioning results in poor memory access efficiency Adjacent threads do not access adjacent memory locations Accesses are not coalesced DRAM bandwidth is poorly utilized 电子科妓女学 O
8 Input Partitioning Affects Memory Access Efficiency – Sectioned partitioning results in poor memory access efficiency – Adjacent threads do not access adjacent memory locations – Accesses are not coalesced – DRAM bandwidth is poorly utilized
Input Partitioning Affects Memory Access Efficiency Sectioned partitioning results in poor memory access efficiency Adjacent threads do not access adjacent memory locations Accesses are not coalesced DRAM bandwidth is poorly utilized 111112222233333 4444 4 Change to interleaved partitioning All threads process a contiguous section of elements They all move to the next section and repeat The memory accesses are coalesced 12 3 4 23412 3 4 1 2 3 4 1 2 3 4 电子神越女学 0
9 Input Partitioning Affects Memory Access Efficiency – Sectioned partitioning results in poor memory access efficiency – Adjacent threads do not access adjacent memory locations – Accesses are not coalesced – DRAM bandwidth is poorly utilized – Change to interleaved partitioning – All threads process a contiguous section of elements – They all move to the next section and repeat – The memory accesses are coalesced 1 1 1 1 1 2 2 2 2 2 3 3 3 3 3 4 4 4 4 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4
Interleaved Partitioning of Input For coalescing and better memory access performance r o g r a mm i n g m a ss e p a Thread 0 Thread 1 Thread 2 Thread 3 0 1 0 2 1 0 0 a-d e-h m-p q-t U-X y-z 电子神越女学 O
10 Interleaved Partitioning of Input – For coalescing and better memory access performance …