Add changes for avx512/aarch64 ldpc encoder optimizations

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newly-generated files for innermost part of the parity bit
generation which, for AVX512, uses the mm512_permutex2var_epi8
instruction and for 128-bit (aarch64) the mm_alignr_epi8 (vextq_s8) in
the computation corresponding to each non-zero bit of the H matrix.

It is generated with ldpctest -n0 -g1. the changes for this are in a
future MR.  I did these changes to compare with the GPU version
(ldpc_encoder_cuda), so that the CPU version is as fast as possible. The
generator will come when we merge the GPU encoder/decoder which also has
a generator for the CUDA version. it was difficult to extract the
changes in ldpctest/ldpc_encoder.c so I just took the generated file.

This allows for removing a very large memcpy and reduces the memory
demand for the parity matrix computation. For the moment this is limited
to largest case in BG1, namely Zc=384. This is the only format used when
the number of segments after codeblock segmentation is large (>8).  This
improves the timing required for ldpc parity bits generation by more
than a factor 2 with AVX512. This significantly reduces the total time
to generate the DLSCH/PDSCH

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This commit is contained in:

Raymond Knopp

2025-09-02 08:55:08 +02:00

committed by Robert Schmidt

parent 48d19e8a91

commit 0e09c7c347

4 changed files with 544 additions and 3 deletions

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openair1/PHY/CODING/nrLDPC_encoder/ldpc384_simd512_alignr_byte.c

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