Hi,
I did some tests of my application, and I noticed that for some grid sizes the performance decreases with the increasement of the grid size. Why the GPU performance does not grow continuously with the increase of the problem size?
Size<-------->Gflop/s
64 64 64<----->61,51927742
128 64 64<—>112,3474286
128 128 64<–>146,1377471<—>sm_efficiency_instance (AVG) 91.51%
256 128 64<–>141,9235423<—>sm_efficiency_instance (AVG) 84.16%
256 256 64<–>164,2279957<—>sm_efficiency_instance (AVG) 91.51%
512 256 64<–>175,8453341
512 512 64<–>175,1639587
1024 512 64<->175,4220063
These tests were executed using GeForce GTX TITAN. The similar trend is for Tesla K20X, and Tesla K80.
I tried to test it with different sizes of dimensions, where only one dimension was changed but it returned the same results.