Add optimized crc32 for Power 8+ processors #750
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Optimized functions for Power will make use of GNU indirect functions, an extension to support different implementations of the same function, which can be selected during runtime. This will be used to provide optimized functions for different processor versions. Since this is a GNU extension, we placed the definition of the Z_IFUNC macro under `contrib/gcc`. This can be reused by other archs as well. Author: Matheus Castanho <msc@linux.ibm.com> Author: Rogerio Alves <rcardoso@linux.ibm.com> Signed-off-by: Manjunath Matti <mmatti@linux.ibm.com>
This commit adds an optimized version for the crc32 function based on crc32-vpmsum from https://github.com/antonblanchard/crc32-vpmsum/ This is the C implementation created by Rogerio Alves <rogealve@br.ibm.com> It makes use of vector instructions to speed up CRC32 algorithm. Author: Rogerio Alves <rcardoso@linux.ibm.com> Signed-off-by: Manjunath Matti <mmatti@linux.ibm.com>
Clang 7 changed the behavior of vec_xxpermdi in order to match GCC's behavior. After this change, code that used to work on Clang 6 stopped to work on Clang >= 7. Tested on Clang 6, 7, 8 and 9. Reference: https://bugs.llvm.org/show_bug.cgi?id=38192 Signed-off-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>
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@madler: Can you look? |
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The patches for Power are also maintained and incorporated in zlib-ng if anybody is interested. |
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Okay, @iii-i has rebased his patch on top of yours and provided it to me. I would like to agree on the order in which you'll have them applied, so I don't need to change it too often. Is that okay with you? |
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I am ok with any order you or @iii-i would like to follow. |
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I'd prefer POWER patches to go first, since they provide a foundation for adding optimized CRC32 implementations. |
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Okay, I agree with that. Thank you |
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Hi, could you please rebase your patches on top of zlib-1.3 version? |
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@ljavorsk: Have you seen the @mmatti-sw PR? |
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Hi, sorry @mmatti-sw for the inconvenience. We've transitioned to zlib-ng from Fedora 40, and thus we don't plan to rebase the zlib anymore. This means, that you can fully focus on the zlib-ng PRs from now on. |
This is a pull request to include all Power8 optimisations rebased to v1.2.13.
The reference PR is #478