Add PCIe bandwidth measurement test

[gsitaram]

Hi @Luke20000429, @joydddd, you can use this simple standalone to measure the bandwidth achieved over PCIe and compare and contrast transfers of

• 1 large buffer vs multiple small buffers
• using pinned memory vs pageable memory
• using hipMemcpy vs hipMemcpyAsync
  There is a convenient run script that you can use to tune your sweep over various parameter values.

My conclusions are the following:

• The performance gets close to peak and is the same whether you transfer a large buffer of size 128MB or 16 small buffers of size 8MB.
• Using pinned memory is better even for hipMemcpy
• The performance of hipMemcpyAsync seems to be better even if we just transfer one time (i.e., iter=1)
• Performance fluctuates when we test on the GPU in our workstation, it is more stable when testing a GPU on a server.

YMMV, so it is best to test on your end with the cards you have access to.

[ooreilly]

Is this code relevant for ksw2? I don't see any dependencies on ksw2.