crc: avoid VPTERNLOGQ on Hygon in crc32_iscsi_by16_10#403
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MaodiMa wants to merge 1 commit intointel:masterfrom
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crc: avoid VPTERNLOGQ on Hygon in crc32_iscsi_by16_10#403MaodiMa wants to merge 1 commit intointel:masterfrom
MaodiMa wants to merge 1 commit intointel:masterfrom
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pablodelara
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Mar 31, 2026
| vpclmulqdq zmm1, zmm0, zmm16, 0x10 | ||
| vpclmulqdq zmm0, zmm0, zmm16, 0x01 | ||
| vpternlogq zmm0, zmm1, [arg2+16*0], 0x96 | ||
| TERNARY_XOR zmm0, zmm1, [arg2+16*0] |
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it works but it is code intrusive and I think it would be better to do it through macro only
| vpternlogq %1, %2, %3, 0x96 | ||
| %endif | ||
| %endmacro | ||
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what about having a macro like this? this should not need more code changes
%ifdef NO_VPTERNLOGQ
%macro vpternlogq 4
%if %4 == 0x96
vpxorq %1, %1, %2
vpxorq %1, %1, %3
%endif
%endmacro
%endif
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I agree with it from the perspective of code changes. Defining vpternlogq as a macro seems to be a bit misleading, but it is okay since this is an edge case.
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Done. I added the other path to prevent the macro from being empty.
Disable VPTERNLOGQ based on platform check, as it reduces IPC on Hygon CPUs. Signed-off-by: Maodi Ma <mamaodi@hygon.cn>
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This is now merged, thanks! |
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Disable VPTERNLOGQ instruction in
crc32_iscsi_by16_10on Hygon CPU.Using VPTERNLOGQ in this case leads to an uarch bottleneck on current Hygon CPU and does not perform ideally. So we would like to use VPXORQ instead. This will leads to ~53.5% speedup according to
make perf:Modification only takes effect on Hygon CPU, based on the result of cpuinfo check.