University of Pennsylvania, CIS 565: GPU Programming and Architecture, Project 2
- Ziwei Zong
- Tested on: Windows 10, i7-5500 @ 2.40GHz 8GB, GTX 950M (Personal)
- Part 1 : CPU Scan & Compaction (see file cpu.cu)
- Part 2 : Naive Scan (naive.cu)
- Part 3 : Work-Efficient Scan & Compaction (efficient.cu)
- Part 4 : Thrust Scan (thrust.cu)
- Part 5 : Radix Sort (in file thrust.cu, RadixSort::sort)
| 32 | 64 | 128 | 256 | 512 | 1024 | |
|---|---|---|---|---|---|---|
| block_naive | 0.062 | 0.061 | 0.060 | 0.062 | 0.064 | 0.078 |
| block_eff | 0.139 | 0.139 | 0.140 | 0.142 | 0.148 | 0.155 |
| block_thrust | 1.060 | 1.180 | 1.200 | 1.100 | 1.029 | 1.090 |
| (ms) | ||||||
| Thus, I choose block size 128 for naive scan, 64 for efficient scan and 512 for thrust scan. |
| Array_length | 2^4 | 2^6 | 2^8 | 2^10 | 2^12 |
|---|---|---|---|---|---|
| cpu | power of 2 | 0.0024 | 0.002304 | 0.002304 | 0.002304 |
| cpu | ! Power of 2 | 0.0023 | 0.002304 | 0.002304 | 0.002336 |
| gpu naïve | power of 2 | 0.027 | 0.0374 | 0.0496 | 0.0609 |
| gpu naïve | ! Power of 2 | 0.0252 | 0.0355 | 0.0473 | 0.0587 |
| gpu efficient | power of 2 | 0.0541 | 0.0765 | 0.0985 | 0.1312 |
| gpu efficient | ! Power of 2 | 0.053 | 0.0748 | 0.0969 | 0.1307 |
| gpu thrust | power of 2 | 0.03293 | 0.3129 | 0.3414 | 0.3854 |
| gpu thrust | ! Power of 2 | 0.3039 | 0.3476 | 0.2955 | 0.3535 |
| (ms) | |||||
| Graph is shown below. | |||||
|  | |||||
|  |
- As the line chart shows, the calculation time for thrust scan doesn't have any specific rules while naive and efficient scan time perform power function correlation with the length of array.
- Weirdly, the time for CPU is very small no matter how long the array is. I was assumming that it was not right to count CPU time using Cuda event so I then tried to use std::clock. However, the result time is even smaller(0.0). Therefore, CPU did perform better than GPU for this task, and that might due to the high cost for memory accessing.
- The naive scan method also performs better than the efficient scan which is not as expected.
** SCAN TESTS **
[ 38 19 38 37 5 47 15 35 0 12 3 0 42 ... 26 0 ]
==== cpu scan, power-of-two ====
StreamCompaction::CPU::scan : exclusive prefix sum.
[ 0 38 57 95 132 137 184 199 234 234 246 249 249 ... 6203 6229 ]
==== cpu scan, non-power-of-two ====
StreamCompaction::CPU::scan : exclusive prefix sum.
[ 0 38 57 95 132 137 184 199 234 234 246 249 249 ... 6146 6190 ]
passed
==== naive scan, power-of-two ====
GPU time for naive scan : 0.0696ms
[ 0 38 57 95 132 137 184 199 234 234 246 249 249 ... 6203 6229 ]
passed
==== naive scan, non-power-of-two ====
GPU time for naive scan : 0.0676ms
[ 0 38 57 95 132 137 184 199 234 234 246 249 249 ... 6146 6190 ]
passed
==== work-efficient scan, power-of-two ====
[ 38 19 38 37 5 47 15 35 0 12 3 0 42 ... 26 0 ]
GPU time for efficient scan : 0.1403ms
[ 0 38 57 95 132 137 184 199 234 234 246 249 249 ... 6203 6229 ]
passed
==== work-efficient scan, non-power-of-two ====
[ 38 19 38 37 5 47 15 35 0 12 3 0 42 ... 44 8 ]
GPU time for efficient scan : 0.1403ms
[ 0 38 57 95 132 137 184 199 234 234 246 249 249 ... 6146 6190 ]
passed
==== thrust scan, power-of-two ====
GPU time for thrust scan : 128.8397ms
[ 0 38 57 95 132 137 184 199 234 234 246 249 249 ... 6203 6229 ]
passed
==== thrust scan, non-power-of-two ====
GPU time for thrust scan : 1.1305ms
[ 0 38 57 95 132 137 184 199 234 234 246 249 249 ... 6146 6190 ]
passed
** STREAM COMPACTION TESTS **
[ 2 3 2 1 3 1 1 1 2 0 1 0 2 ... 0 0 ]
==== cpu compact without scan, power-of-two ====
[ 2 3 2 1 3 1 1 1 2 1 2 1 1 ... 2 1 ]
passed
==== cpu compact without scan, non-power-of-two ====
[ 2 3 2 1 3 1 1 1 2 1 2 1 1 ... 3 2 ]
passed
==== cpu compact with scan ====
StreamCompaction::CPU::scan : exclusive prefix sum.
[ 2 3 2 1 3 1 1 1 2 1 2 1 1 ... 2 1 ]
passed
==== work-efficient compact, power-of-two ====
[ 2 3 2 1 3 1 1 1 2 0 1 0 2 ... 0 0 ]
[ 2 3 2 1 3 1 1 1 2 1 2 1 1 ... 2 1 ]
passed
==== work-efficient compact, non-power-of-two ====
[ 2 3 2 1 3 1 1 1 2 0 1 0 2 ... 0 0 ]
[ 2 3 2 1 3 1 1 1 2 1 2 1 1 ... 3 2 ]
passed
** Radix Sort **
==== Radix Sort, power-of-two ====
[ 4 7 2 6 3 5 1 0 ]
[ 4 2 6 0 7 3 5 1 ]