From nobody Tue Nov 26 13:33:28 2024 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=none dis=none) header.from=linaro.org ARC-Seal: i=1; a=rsa-sha256; t=1707985039; cv=none; d=zohomail.com; s=zohoarc; b=jojDML8Un6lusz2/B36+PJXyhmkrlk/kzyJoV59AHtK2okVQHg9ct8ppJkNMl5WlncDdi+KOV3xXb+mXZQk3VsQOIFsfFQyYP/yWPx209pibtcysy53RGktF/K6BV4XQ0ZJaSOxH9le9qzIYlSD82IUltqd8u8rUfRiyrvf82k4= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1707985039; h=Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:Subject:To:To:Message-Id:Reply-To; bh=Sc6Au+pExfgVbkEVt3xBcrgjk6DJCZWLxXzjjgNJTcI=; b=f8gvbIRKVaifElv8ozBCeRy4KSb56c2M6fV1fkVfvfidk+RpJGvWiB4hWMH5zBCCoPpd6Qdf0LxBsgURvG1XMuq3WcUXG4g8rmHPok8YF7FqeMZZ3vFK0EM6cnqV/FnZ89tTGd2PVTjZ349sqxUl5jRBWiw4zjitetUPwRKA1DA= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=none dis=none) Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 170798503985160.552759661507594; Thu, 15 Feb 2024 00:17:19 -0800 (PST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1raWu8-0007fJ-RD; Thu, 15 Feb 2024 03:15:36 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1raWtV-00072x-P3 for qemu-devel@nongnu.org; Thu, 15 Feb 2024 03:14:58 -0500 Received: from mail-pj1-x102c.google.com ([2607:f8b0:4864:20::102c]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1raWtU-0001NL-2d for qemu-devel@nongnu.org; Thu, 15 Feb 2024 03:14:57 -0500 Received: by mail-pj1-x102c.google.com with SMTP id 98e67ed59e1d1-290ec261a61so409173a91.0 for ; Thu, 15 Feb 2024 00:14:55 -0800 (PST) Received: from stoup.. (173-197-098-125.biz.spectrum.com. [173.197.98.125]) by smtp.gmail.com with ESMTPSA id qc14-20020a17090b288e00b0029900404e11sm807755pjb.27.2024.02.15.00.14.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 15 Feb 2024 00:14:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1707984894; x=1708589694; darn=nongnu.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=Sc6Au+pExfgVbkEVt3xBcrgjk6DJCZWLxXzjjgNJTcI=; b=WwqMPmy6Kr5IbEMgHOJ3D+901EKZpQdAzh2H/J1P2EwG4jdtru6x6hlWi5hiZa+UAZ KW0M2K8zLkYXAhmUcOrnVl5cg4iVHm5JDmE3ATlju4SN1xoAIVxfLe9WdDYgQ3RaxRMs /yDkOIX6uYgd+1iIsaiV6x1UpwbAbjdifyYrhtNkvkxkxWMMZJpVJKfzZuLQWFI4ni1s jTlTM2Fl47M9eaPVudQISbc/w6DovQYuSe6WxQYFYBG6iXs6s0zs/cP1ZKqZzVFfYurp YgSNbB+LPGiwjOwDutRxX8+tFwVGYdnVmrCBbn6zJcu1l+8IfCZwXv7U/RIIkPaVGllJ GLrw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1707984894; x=1708589694; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=Sc6Au+pExfgVbkEVt3xBcrgjk6DJCZWLxXzjjgNJTcI=; b=B24Prdun6mjGAKNSKOeE9ZjTID6so6IF3thX9XrTBjiv5JDrA89xmowSdNE+zNYYWB nLa2LQOlli6jzl0dSwe3ke96qRCjIUfUyfmyo/+8rMBIoHjthP+QEtPVujltxebfCjsM ZThPMA/hv7Bo6hrlEKTJZDXS2h+4bGwJlCmfC+rPIEJ8oD3xiuZoF5SSl+1WkC4+054C zQYKE+NQUvNlBrUSWnIvw4zeoDRy/SX65CqAC1m40lsZRMn0/QUNpbLxPJhNipFDZhs8 +H7GyM6HkVu6gD1Pkkp9ciqQfeKVJio72ZHOQOdY6eiF7R6mdRR/NyU+jqUwiBbMsFaG E7xw== X-Gm-Message-State: AOJu0YxYdSXfEKnJ9ykRFffNTqtUW1bWsNg7hu8AciIYYFNjRI0CQGxX W4tS8D6LDfrsuPHQyZ5602XaeBMViD+hufAwZ1h10ibIzv7wa6AMin7RJeexW+3S8pbCipWcNNL b X-Google-Smtp-Source: AGHT+IFWlzoGQi8xBe5pHhUEZ8Bm2klpBfKU1YBM5dEXTh/dltyNCile9CFhCEEoEYmWbebD0wqzZQ== X-Received: by 2002:a17:90b:1e01:b0:298:e10b:1776 with SMTP id pg1-20020a17090b1e0100b00298e10b1776mr1136813pjb.8.1707984894651; Thu, 15 Feb 2024 00:14:54 -0800 (PST) From: Richard Henderson To: qemu-devel@nongnu.org Cc: amonakov@ispras.ru, mmromanov@ispras.ru Subject: [PATCH v4 02/10] util/bufferiszero: Remove AVX512 variant Date: Wed, 14 Feb 2024 22:14:41 -1000 Message-Id: <20240215081449.848220-3-richard.henderson@linaro.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240215081449.848220-1-richard.henderson@linaro.org> References: <20240215081449.848220-1-richard.henderson@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2607:f8b0:4864:20::102c; envelope-from=richard.henderson@linaro.org; helo=mail-pj1-x102c.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @linaro.org) X-ZM-MESSAGEID: 1707985041962100005 Content-Type: text/plain; charset="utf-8" From: Alexander Monakov Thanks to early checks in the inline buffer_is_zero wrapper, the SIMD routines are invoked much more rarely in normal use when most buffers are non-zero. This makes use of AVX512 unprofitable, as it incurs extra frequency and voltage transition periods during which the CPU operates at reduced performance, as described in https://travisdowns.github.io/blog/2020/01/17/avxfreq1.html Signed-off-by: Mikhail Romanov Signed-off-by: Alexander Monakov Reviewed-by: Richard Henderson Message-Id: <20240206204809.9859-4-amonakov@ispras.ru> Signed-off-by: Richard Henderson --- util/bufferiszero.c | 38 +++----------------------------------- 1 file changed, 3 insertions(+), 35 deletions(-) diff --git a/util/bufferiszero.c b/util/bufferiszero.c index f5a3634f9a..641d5f9b9e 100644 --- a/util/bufferiszero.c +++ b/util/bufferiszero.c @@ -64,7 +64,7 @@ buffer_zero_int(const void *buf, size_t len) } } =20 -#if defined(CONFIG_AVX512F_OPT) || defined(CONFIG_AVX2_OPT) || defined(__S= SE2__) +#if defined(CONFIG_AVX2_OPT) || defined(__SSE2__) #include =20 /* Note that each of these vectorized functions require len >=3D 64. */ @@ -128,41 +128,12 @@ buffer_zero_avx2(const void *buf, size_t len) } #endif /* CONFIG_AVX2_OPT */ =20 -#ifdef CONFIG_AVX512F_OPT -static bool __attribute__((target("avx512f"))) -buffer_zero_avx512(const void *buf, size_t len) -{ - /* Begin with an unaligned head of 64 bytes. */ - __m512i t =3D _mm512_loadu_si512(buf); - __m512i *p =3D (__m512i *)(((uintptr_t)buf + 5 * 64) & -64); - __m512i *e =3D (__m512i *)(((uintptr_t)buf + len) & -64); - - /* Loop over 64-byte aligned blocks of 256. */ - while (p <=3D e) { - __builtin_prefetch(p); - if (unlikely(_mm512_test_epi64_mask(t, t))) { - return false; - } - t =3D p[-4] | p[-3] | p[-2] | p[-1]; - p +=3D 4; - } - - t |=3D _mm512_loadu_si512(buf + len - 4 * 64); - t |=3D _mm512_loadu_si512(buf + len - 3 * 64); - t |=3D _mm512_loadu_si512(buf + len - 2 * 64); - t |=3D _mm512_loadu_si512(buf + len - 1 * 64); - - return !_mm512_test_epi64_mask(t, t); - -} -#endif /* CONFIG_AVX512F_OPT */ - /* * Make sure that these variables are appropriately initialized when * SSE2 is enabled on the compiler command-line, but the compiler is * too old to support CONFIG_AVX2_OPT. */ -#if defined(CONFIG_AVX512F_OPT) || defined(CONFIG_AVX2_OPT) +#if defined(CONFIG_AVX2_OPT) # define INIT_USED 0 # define INIT_LENGTH 0 # define INIT_ACCEL buffer_zero_int @@ -188,9 +159,6 @@ select_accel_cpuinfo(unsigned info) unsigned len; bool (*fn)(const void *, size_t); } all[] =3D { -#ifdef CONFIG_AVX512F_OPT - { CPUINFO_AVX512F, 256, buffer_zero_avx512 }, -#endif #ifdef CONFIG_AVX2_OPT { CPUINFO_AVX2, 128, buffer_zero_avx2 }, #endif @@ -208,7 +176,7 @@ select_accel_cpuinfo(unsigned info) return 0; } =20 -#if defined(CONFIG_AVX512F_OPT) || defined(CONFIG_AVX2_OPT) +#if defined(CONFIG_AVX2_OPT) static void __attribute__((constructor)) init_accel(void) { used_accel =3D select_accel_cpuinfo(cpuinfo_init()); --=20 2.34.1