Also on other GPUS.

So far I have tested on:

  size    tflops_cublas  tflops_my  diff      gpu
  4096²   28.7-28.8      32.5       +13%      4070ts
  8192²   27.7-28.2      33.5       +19-21%   4070ts
  4096²   9.9-10.0       10.1-10.2  +1-2%     1080ti
  4096²   3.8-4.3        6.7        +56-76%   T4