Alignment of memory returned by cuMemAllocHost?

Accelerated Computing CUDA CUDA Programming and Performance
1

Hi all,
is there any documentation about the alignment of the memory returned by cuMemAllocHost / cuMemHostAlloc ?

The documentation from CUDA 10.2 doesn’t say anything about it (while for cuMemAlloc / cuMemAllocManaged it does specify that “the allocated memory is suitably aligned for any kind of variable”.

From a quick test (Linux, GTX 960M, CUDA 10.2) it looks like the memory is aligned to1024 bytes - but it would be useful to know if this is just and accident or something guaranteed by the CUDA driver.

Thank you,
.Andrea

2

Since cudaMemHostAlloc allocates pinned memory, I imagine it would be on aligned to a page. Your test seems to indicate differently, Usually, alignment of memory falls into the realm of “implementation/hardware dependent”, so I wouldn’t assume anything about it unless the documentation explicitly states otherwise.