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项目作者： Michaelangel007

项目描述 ：
Cache Line Memory Access Speed Row vs Col
高级语言： C++
项目地址: git://github.com/Michaelangel007/cache_line_speed.git
创建时间： 2016-12-21T15:02:55Z
项目社区：https://github.com/Michaelangel007/cache_line_speed
开源协议：GNU General Public License v3.0
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Cache Line Speed: Row vs Col memory access

Let’s allocate an 32-bit array of 1,073,741,824 elements for a total size of 4GB.

We’ll fill this array from 0,1,2,…n-1 and then sum it.

  1. Sum 1+2+3+...+n = n*(n+1)/2
  2. Sum of 0+1+2+...+n-1 = (n-1)*n/2

Sum array of 1,073,741,824 elements = 576,460,751,766,552,576.

i += Bytes Op/s Time
1 4 1 G/s 00:00:00s
2 8 1 G/s 00:00:00s
4 16 733 M/s 00:00:01s
8 32 388 M/s 00:00:02s
16 64 213 M/s 00:00:04s
32 128 141 M/s 00:00:07s
64 256 116 M/s 00:00:08s
128 512 115 M/s 00:00:08s
256 1,024 115 M/s 00:00:08s
512 2,048 100 M/s 00:00:10s
1024 4,096 66 M/s 00:00:15s

Notes:

  • += Stride element delta access
  • Bytes Stride delta in bytes

Tests

Running tests which does bin/col #

  1. Stride: [1] @ 4 bytes
  2. Len: 1,073,741,824
  3. int: 4
  4. Mem: 4,294,967,296
  5. Sum= 576,460,751,766,552,576  pass
  6. 1 G cells/s 1 seconds = 00:00:00
  8. Stride: [2] @ 8 bytes
  9. Len: 1,073,741,824
  10. int: 4
  11. Mem: 4,294,967,296
  12. Sum= 576,460,751,766,552,576  pass
  13. 1 G cells/s 1 seconds = 00:00:00
  15. Stride: [4] @ 16 bytes
  16. Len: 1,073,741,824
  17. int: 4
  18. Mem: 4,294,967,296
  19. Sum= 576,460,751,766,552,576  pass
  20. 733 M cells/s 1 seconds = 00:00:01
  22. Stride: [8] @ 32 bytes
  23. Len: 1,073,741,824
  24. int: 4
  25. Mem: 4,294,967,296
  26. Sum= 576,460,751,766,552,576  pass
  27. 388 M cells/s 3 seconds = 00:00:02
  29. Stride: [16] @ 64 bytes
  30. Len: 1,073,741,824
  31. int: 4
  32. Mem: 4,294,967,296
  33. Sum= 576,460,751,766,552,576  pass
  34. 213 M cells/s 5 seconds = 00:00:04
  36. Stride: [32] @ 128 bytes
  37. Len: 1,073,741,824
  38. int: 4
  39. Mem: 4,294,967,296
  40. Sum= 576,460,751,766,552,576  pass
  41. 141 M cells/s 7 seconds = 00:00:07
  43. Stride: [64] @ 256 bytes
  44. Len: 1,073,741,824
  45. int: 4
  46. Mem: 4,294,967,296
  47. Sum= 576,460,751,766,552,576  pass
  48. 116 M cells/s 9 seconds = 00:00:08
  50. Stride: [128] @ 512 bytes
  51. Len: 1,073,741,824
  52. int: 4
  53. Mem: 4,294,967,296
  54. Sum= 576,460,751,766,552,576  pass
  55. 115 M cells/s 9 seconds = 00:00:08
  57. Stride: [256] @ 1024 bytes
  58. Len: 1,073,741,824
  59. int: 4
  60. Mem: 4,294,967,296
  61. Sum= 576,460,751,766,552,576  pass
  62. 115 M cells/s 9 seconds = 00:00:08
  64. Stride: [512] @ 2048 bytes
  65. Len: 1,073,741,824
  66. int: 4
  67. Mem: 4,294,967,296
  68. Sum= 576,460,751,766,552,576  pass
  69. 100 M cells/s 10 seconds = 00:00:10
  71. Stride: [1024] @ 4096 bytes
  72. Len: 1,073,741,824
  73. int: 4
  74. Mem: 4,294,967,296
  75. Sum= 576,460,751,766,552,576  pass
  76. 66 M cells/s 16 seconds = 00:00:15