[GitHub] [tvm] tqchen commented on pull request #12564: [Runtime] Change default alignment to 64 bytes.

[GitBox <gi...@apache.org>]

tqchen commented on PR #12564:
URL: https://github.com/apache/tvm/pull/12564#issuecomment-1225915787

   There are two parts of the perspective that comes into the story:
   
   - P0: The alignment of the allocator
   - P1: The alignment assumption of the compiler
   
   P1 affects how compiler generates code, e.g. if we assume that the code is aligned to 128bytes, then compiler can generate aligned store/load safely. P0 affects the array we allocate, we always need to allocate memory that is larger than P1 assumption made by the compiler.
   
   Right now the two are roughly tied together, with the exception of `kHexagonAllocAlignment`, which enforces P0. 
   
   The PyTorch issue was caused by P1 -- we are making assumption of 128 byte alignment while pytorch arrays are commonly aligned to 64 bytes.
   
   Currently, P1 is supplied by the buffer construct, which do not (yet) depend on the target.  Agree with @kparzysz-quic that minimum alignment requirement can be part of the target, and we need to find good ways to set them onto the buffer. 
   
   As a short workaround, we can detect P1 settings(of buffers) in early stage of TIR compilation and amend them for devices like HVX
    


-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: commits-unsubscribe@tvm.apache.org

For queries about this service, please contact Infrastructure at:
users@infra.apache.org