max memory with pinned data

Hi,
Could someone tell me how PGI Fortran define the maximum available memory for pinned host data.


Tuan

Hi Tuan,

It depends on how much the OS has available. CUDA Fortran just makes a call to the OS to request the memory. If the request fails, then regular memory will be used.

  • Mat

Is that limited by the physical RAM memory? As data in pinned memory is faster for data transfer to device memory than normal host data, I don’t know which kind of memory will hold pinned data?

Tuan.

Hi Tuan,

Is that limited by the physical RAM memory?

This would be the max assuming the OS is able to give you all the physical memory. Realistically it will be lower and depend upon what else is happening on your system.

As data in pinned memory is faster for data transfer to device memory than normal host data, I don’t know which kind of memory will hold pinned data?

Our internal testing shows that pinned memory only helps when you can reuse it for multiple transfers. Otherwise, it doesn’t help.

  • Mat

Gotcha,
Tuan