ch4/ofi: make seg_sz a multiple of datatype size - #7897
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| if (elem_sz) { | ||
| seg_sz -= (seg_sz % elem_sz); | ||
| } | ||
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This is not robust since it assumes 1. contiguous datatype, 2. no alignment requirement. Rather, we should adjust am_hdr_sz so it landed on MAX_ALIGNMENT. I'll push a commit on top of this.
The am payload data need land on MAX_ALIGNMENT or the limited seg_sz may
chop the data elements in half, resulting either ubsan error or
MPIR_Typerep_{pack,unpack} issue.
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test:mpich/ch4/ofi |
We never call MPIDI_OFI_am_init_sreq with MPIDI_OFI_AMREQUEST(sreq, sreq_hdr) set. Remove the dead branch.
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test:mpich/ch4/ofi |
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Pull Request Description
This PR changes
seg_szto a multiple of the element size inMPIDI_OFI_am_isend_pipeline.This is done because the
packed_sizeis being made a multiple of the element sizein MPIR_Typerep_pack, but
seg_szhas no such restriction, so in some cases they do notmatch.
This is a potential fix for Issue #7881 .
With
MPIR_CVAR_CH4_OFI_ENABLE_RMA=0the reproducer in that issue hitsAssertion failed in file [...]/ofi/ofi_am_impl.h at line 413: packed_size == seg_sz,which led to this PR.
Possibly there are other ways to get this work, but changing
seg_szto a multiple ofthe element size seemed the cleanest to me. The code patch here is copied from
similar code in MPIR_Typerep_pack to match it exactly.
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