[{"id":3684049,"web_url":"http://patchwork.ozlabs.org/comment/3684049/","msgid":"","list_archive_url":null,"date":"2026-04-29T13:20:47","subject":"Re: [PATCH v1 1/1] x86: Enable Prefer_No_AVX512 for Hygon model 0x8","submitter":{"id":4387,"url":"http://patchwork.ozlabs.org/api/people/4387/","name":"H.J. Lu","email":"hjl.tools@gmail.com"},"content":"On Wed, Apr 29, 2026 at 4:22 PM Jiamei Xie wrote:\n>\n> From: xiejiamei \n>\n> Extend the Prefer_No_AVX512 tuning to cover Hygon model 0x8.\n>\n> Benchmarks on Hygon platforms show that EVEX implementations\n> are often more profitable than AVX512 paths. The existing logic\n> already enables Prefer_No_AVX512 for model 0x7. Apply the same\n> preference to model 0x8 to ensure consistent IFUNC selection\n> behavior across newer Hygon processors.\n>\n> Signed-off-by: xiejiamei \n> ---\n> sysdeps/x86/cpu-features.c | 2 +-\n> 1 file changed, 1 insertion(+), 1 deletion(-)\n>\n> diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c\n> index 73ee4f2bb8..a453136827 100644\n> --- a/sysdeps/x86/cpu-features.c\n> +++ b/sysdeps/x86/cpu-features.c\n> @@ -1135,7 +1135,7 @@ disable_tsx:\n> cpu_features->preferred[index_arch_AVX_Fast_Unaligned_Load]\n> &= ~bit_arch_AVX_Fast_Unaligned_Load;\n> }\n> - else if (model == 0x7)\n> + else if (model == 0x7 || model == 0x8)\n> {\n> /* Benchmarks indicate evex can be more profitable on Hygon\n> hardware than AVX512. */\n> --\n> 2.43.0\n>\n>\n\nLGTM.\n\nReviewed-by: H.J. 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Wed, 29 Apr 2026\n 06:21:25 -0700 (PDT)","MIME-Version":"1.0","References":"<20260429082030.310472-1-xiejiamei@hygon.cn>\n <20260429082030.310472-2-xiejiamei@hygon.cn>","In-Reply-To":"<20260429082030.310472-2-xiejiamei@hygon.cn>","From":"\"H.J. Lu\" ","Date":"Wed, 29 Apr 2026 21:20:47 +0800","X-Gm-Features":"AVHnY4K_mCRrMKIVObE0XfZ3EjmKTKLbEC7-hagzh_JtFNIpTJ7vJ_jVScAPsCI","Message-ID":"\n ","Subject":"Re: [PATCH v1 1/1] x86: Enable Prefer_No_AVX512 for Hygon model 0x8","To":"Jiamei Xie ","Cc":"libc-alpha@sourceware.org, lijing@hygon.cn","Content-Type":"text/plain; charset=\"UTF-8\"","Content-Transfer-Encoding":"quoted-printable","X-BeenThere":"libc-alpha@sourceware.org","X-Mailman-Version":"2.1.30","Precedence":"list","List-Id":"Libc-alpha mailing list ","List-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Errors-To":"libc-alpha-bounces~incoming=patchwork.ozlabs.org@sourceware.org"}}]