I measured cycles of project using OpenMP on TMDSEVM6678L. The project is 512sample convolution process.
At First, I measured cycles without optimization.The result is as follow.
|
1core |
84884856cycles |
| 1core(using openMP) | 84303228cycles |
| 2cores(using openMP) | 43867970cycles |
| 3cores(using openMP) | 33688320cycles |
| 4cores(using openMP) | 23475722cycles |
| 5cores(using openMP) | 23613656cycles |
| 6cores(using openMP) | 18571906cycles |
| 7cores(using openMP) | 18762366cycles |
| 8cores(using openMP) | 13808076cycles |
This is the result of as expected.
Second, I set optimization level 3 and mt option. And I measured cycles.
|
1core |
2930930cycles |
| 1core(using openMP) | 6405540cycles |
| 2cores(using openMP) | 4941541cycles |
| 3cores(using openMP) | 4454739cycles |
| 4cores(using openMP) | 3990873cycles |
| 5cores(using openMP) | 4107885cycles |
| 6cores(using openMP) | 3954131cycles |
| 7cores(using openMP) | 4175821cycles |
| 8cores(using openMP) | 4055629cycles |
My question is as follow.
1.Why do the cycles of 1core using openMP increase compared with 1core without openMP?
2.Why the cycles of multi core using openMP do not decrease? I expected that t cycles are reduced in accordance with the number of cores.
Many thanks.
