add detection for zen 5 #56967
add detection for zen 5 #56967
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src/processor_x86.cpp
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| @@ -236,6 +237,7 @@ constexpr auto znver2 = znver1 | get_feature_masks(clwb, rdpid, wbnoinvd); | |||
| constexpr auto znver3 = znver2 | get_feature_masks(shstk, pku, vaes, vpclmulqdq); | |||
| constexpr auto znver4 = znver3 | get_feature_masks(avx512f, avx512cd, avx512dq, avx512bw, avx512vl, avx512ifma, avx512vbmi, | |||
| avx512vbmi2, avx512vnni, avx512bitalg, avx512vpopcntdq, avx512bf16, gfni, shstk, xsaves); | |||
| constexpr auto znver5 = znver4 | get_feature_masks(avxvnni, movdiri, movdir64b, avx512vp2intersect, /*prefetchi,*/ avxvnni); | |||
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I assume prefetchi needs to be added to src/features_x86.h, but I didn't know how
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Line 113 in 4750dc2
Now you need to look in the CPU docs for how prefetchi is encoded.
From the "Processor Programming Reference" https://www.amd.com/content/dam/amd/en/documents/processor-tech-docs/programmer-references/57896.zip
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https://github.com/llvm/llvm-project/blob/3edbe36c3eb01d1c35ac1761da108e3a493258ee/clang/lib/Headers/cpuid.h#L220 The bits are here, though you will to add the
// EAX=7,ECX=1: EDX
branch IIUC
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Thanks for the hints! What I don't get is where the 32 * 8, 32 * 9 etc. is coming from.
Is this the correct patch or are the 32 * 9 bits incorrect?
diff --git a/src/features_x86.h b/src/features_x86.h
index 2ecc8fee32..b817781404 100644
--- a/src/features_x86.h
+++ b/src/features_x86.h
@@ -113,6 +113,9 @@ JL_FEATURE_DEF(wbnoinvd, 32 * 8 + 9, 0)
JL_FEATURE_DEF(avxvnni, 32 * 9 + 4, 120000)
JL_FEATURE_DEF(avx512bf16, 32 * 9 + 5, 0)
+// EAX=7,ECX=1: EDX
+JL_FEATURE_DEF(prefetchi, 32 * 9 + 20, 0)
+
// EAX=0x14,ECX=0: EBX
JL_FEATURE_DEF(ptwrite, 32 * 10 + 4, 0)There was a problem hiding this comment.
I'm implementing it and maybe adding some comments
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Won't we need to wait for #56130 to be merged before we can use Zen5 since that is only in LLVM 19? |
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Yes, to take full advantage of zen 5 features I believe LLVM 19 is needed, but this PR is still an improvement since we now fall back to the |
src/features_x86.h
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| JL_FEATURE_DEF(avx512vnniw, 32 * 4 + 2, 0) | ||
| JL_FEATURE_DEF(avx512fmaps, 32 * 4 + 3, 0) | ||
| JL_FEATURE_DEF(uintr, 32 * 4 + 5, 140000) |
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Isn't the last statement a comment which LLVM version introduced support?
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As it turns out those were never implemented :)
ref llvm/llvm-project@149a150