From patchwork Tue Oct 21 05:53:03 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: litenglong X-Patchwork-Id: 122319 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 9193F3858C20 for ; Tue, 21 Oct 2025 05:54:20 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 9193F3858C20 X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from mailgw.kylinos.cn (mailgw.kylinos.cn [124.126.103.232]) by sourceware.org (Postfix) with ESMTPS id D2B3D3858D37 for ; Tue, 21 Oct 2025 05:53:40 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org D2B3D3858D37 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=kylinos.cn Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=kylinos.cn ARC-Filter: OpenARC Filter v1.0.0 sourceware.org D2B3D3858D37 Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=124.126.103.232 ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1761026021; cv=none; b=dA9CznuLBn9Cf+cuka973o29x1BIeb5rnBAmC3DafyLuh2f3uxmaIA/Q3ZqzBBsVw+H0Sjzov5TVbhOdH7FN+BMc1RwNKXPGQANECN7YuN7YAliGJYin9AsRX7JwKWNUnhpJsoJxoYlB+RckRdMauMz+SqZhYn9QlGZDJ50ajjk= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1761026021; c=relaxed/simple; bh=nzPRg/xfp0k7B6z/AJCoi6vi7oLJuZeCtQE6bI3c9eY=; h=From:To:Subject:Date:Message-Id:MIME-Version; b=TnMRqHHERtK/3Vdbx4htKPmBWPPU4oUbE53Svo0J1JmeDwNCxXexbbhXoxHYnJ8bGKSKPLdCOAOczSGi/tn4HFQWeccyFsuu0NxY4pdSD39/itW4Ju3U54Yo6LDMnjuSugGvVG6Nj9XcYFYYAI+0rinF8qzw1ZjcYR07L5O/DuY= ARC-Authentication-Results: i=1; server2.sourceware.org DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org D2B3D3858D37 X-UUID: 481ad832ae4211f0a38c85956e01ac42-20251021 X-CTIC-Tags: HR_CC_COUNT, HR_CC_DOMAIN_COUNT, HR_CC_NAME, HR_CTE_8B, HR_CTT_MISS HR_DATE_H, HR_DATE_WKD, HR_DATE_ZONE, HR_FROM_NAME, HR_SJ_DIGIT_LEN HR_SJ_LANG, HR_SJ_LEN, HR_SJ_LETTER, HR_SJ_NOR_SYM, HR_SJ_PHRASE HR_SJ_PHRASE_LEN, HR_SJ_WS, HR_TO_COUNT, HR_TO_DOMAIN_COUNT, HR_TO_NO_NAME IP_TRUSTED, SRC_TRUSTED, DN_TRUSTED, SA_UNTRUSTED, SA_LOWREP SA_EXISTED, SN_UNTRUSTED, SN_LOWREP, SN_EXISTED, SPF_NOPASS DKIM_NOPASS, DMARC_NOPASS X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.3.6, REQID:1412ecfc-49dd-4017-b9dc-770c0f150ad2, IP:15, U RL:0,TC:0,Content:0,EDM:0,RT:0,SF:-15,FILE:0,BULK:0,RULE:Release_Ham,ACTIO N:release,TS:0 X-CID-INFO: VERSION:1.3.6, REQID:1412ecfc-49dd-4017-b9dc-770c0f150ad2, IP:15, URL :0,TC:0,Content:0,EDM:0,RT:0,SF:-15,FILE:0,BULK:0,RULE:Release_Ham,ACTION: release,TS:0 X-CID-META: VersionHash:a9d874c, CLOUDID:5ba176bd0eaeb3a5d7398cb36aa5832c, BulkI D:251021135336320KDGEB,BulkQuantity:0,Recheck:0,SF:17|19|24|44|66|78|81|82 |102|850,TC:nil,Content:0|50,EDM:-3,IP:-2,URL:0,File:nil,RT:nil,Bulk:nil,Q S:nil,BEC:nil,COL:0,OSI:0,OSA:0,AV:0,LES:1,SPR:NO,DKR:0,DKP:0,BRR:0,BRE:0, ARC:0 X-CID-BVR: 2,SSN|SDN X-CID-BAS: 2,SSN|SDN,0,_ X-CID-FACTOR: TF_CID_SPAM_FSI,TF_CID_SPAM_SNR,TF_CID_SPAM_FAS,TF_CID_SPAM_FSD X-CID-RHF: D41D8CD98F00B204E9800998ECF8427E X-UUID: 481ad832ae4211f0a38c85956e01ac42-20251021 X-User: litenglong@kylinos.cn Received: from localhost.localdomain [(39.156.73.13)] by mailgw.kylinos.cn (envelope-from ) (Generic MTA) with ESMTP id 297457772; Tue, 21 Oct 2025 13:53:34 +0800 From: litenglong To: libc-alpha@sourceware.org Cc: litenglong , gaoxiang Subject: [PATCH] x86: Disable AVX Fast Unaligned Load on Hygon 1/2/3 Date: Tue, 21 Oct 2025 13:53:03 +0800 Message-Id: <20251021055302.75139-1-litenglong@kylinos.cn> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 X-Spam-Status: No, score=-13.3 required=5.0 tests=BAYES_00, GIT_PATCH_0, KAM_DMARC_STATUS, RCVD_IN_VALIDITY_RPBL_BLOCKED, RCVD_IN_VALIDITY_SAFE_BLOCKED, SPF_HELO_NONE, SPF_PASS, TXREP, UNPARSEABLE_RELAY autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.30 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: libc-alpha-bounces~patchwork=sourceware.org@sourceware.org - Performance testing revealed significant memcpy performance degradation when bit_arch_AVX_Fast_Unaligned_Load is enabled on Hygon 3. - Hygon confirmed AVX performance issues in certain memory functions. - Glibc benchmarks show SSE outperforms AVX for memcpy/memmove/memset/strcmp/strcpy/strlen and so on. - Hardware differences primarily in floating-point operations don't justify AVX usage for memory operations. Reviewed-by: gaoxiang Signed-off-by: litenglong --- sysdeps/x86/cpu-features.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c index b67ef541dd..286cbfb1e2 100644 --- a/sysdeps/x86/cpu-features.c +++ b/sysdeps/x86/cpu-features.c @@ -1123,6 +1123,11 @@ disable_tsx: hardware. */ cpu_features->preferred[index_arch_Avoid_Non_Temporal_Memset] &= ~bit_arch_Avoid_Non_Temporal_Memset; + if (model < 0x4) { + /* Unaligned AVX loads are slower. */ + cpu_features->preferred[index_arch_AVX_Fast_Unaligned_Load] + &= ~bit_arch_AVX_Fast_Unaligned_Load; + } } else {