From nobody Tue Feb 10 13:17:09 2026 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=1664894252; cv=none; d=zohomail.com; s=zohoarc; b=EEV/wckoajNle5bk8iMW1yRvEwA/tRYCTeYoxLLDcePaA+1Fx30W+IbbnFrEmEzkddB3isly4EIPiXbCSLSFuqGkC0FLNPHazVgLqZ3ZECStOfXlaEpZ7CmcIvCuno0eEHRlc5Q+xEYR9Z6+Br0boRCD5DGPqG3Mrfd5mAoueBQ= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1664894252; h=Content-Type:Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=nRMEXB7YPadVE5hdI4341oxvhxYYKiN9qf3uVsx6pus=; b=czB84unsJPffYGuobYCoO0+5PVXEby3LuGPUEjPoOl8SWdrKJUaeMi2cEbvrk7Vr3SOxZFhnnanFKkhjo+7Rr18N/FVYwcm9KPVzRLdSYZdWz5LSpW7BtuPMUAwZw6Jbp0cMi8j0uz0ddmp+rrv3gNBRVo0v5/KFYmV5EJIFPKQ= 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 1664894252547243.56723989928537; Tue, 4 Oct 2022 07:37:32 -0700 (PDT) Received: from localhost ([::1]:55606 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ofj33-0000WP-4I for importer@patchew.org; Tue, 04 Oct 2022 10:37:30 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59820) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ofidP-000238-RS for qemu-devel@nongnu.org; Tue, 04 Oct 2022 10:10:59 -0400 Received: from mail-pf1-x433.google.com ([2607:f8b0:4864:20::433]:35473) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1ofidN-0004Hm-Vt for qemu-devel@nongnu.org; Tue, 04 Oct 2022 10:10:59 -0400 Received: by mail-pf1-x433.google.com with SMTP id i6so13258191pfb.2 for ; Tue, 04 Oct 2022 07:10:57 -0700 (PDT) Received: from stoup.. ([2605:ef80:8015:12b0:403e:a15b:ff5e:d439]) by smtp.gmail.com with ESMTPSA id y5-20020aa79ae5000000b00561382a5a25sm1240357pfp.26.2022.10.04.07.10.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 04 Oct 2022 07:10:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date; bh=nRMEXB7YPadVE5hdI4341oxvhxYYKiN9qf3uVsx6pus=; b=XWj2HLRvJXtFgF9UIpAXphNml4iv/Ofefy0h3sYt4KBgigALpnHbkrIPlqGKZAth9d N/GwtYw3EIW+rt90GKWCmxyvA2PQM9TJuvuRFq40kfnsFDxc4Bwhio+4tFzcbAJSlkDq 4psdD7KmqoSoZIGyK/RORBSN8U+x7LIwc4W0bhtbLjZ1sB4WA8MqZr+KIXtWLkw6pfRS v/p+uczaJRz49obUXQz6Oq/c9jMy6DFTfTtxPDlYEpzDJGvlDjQh3bB9tlj5WFqoN/Ar E9eO1H4yFn0zHrFVuT3gfWG7zwQWODsoid/i+95cVDaQqe9IimpIAVsrI3Z9QWhzYSv/ B2Hw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; 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; bh=nRMEXB7YPadVE5hdI4341oxvhxYYKiN9qf3uVsx6pus=; b=eWz0U3HVbaA4PLLI4okkV0GF/poA5wTxxKjCfAEkYUUWzI4CJPbaB/nPKFX08/j072 MdkHQ82q3Oz/Ev/0CTySmjclzDSS/C8kRTX4GkkQ0i01Xg8uCzx+XEGEPsL7CV9MDxEC zIk+pSUS9AP1bp3jLqLrr3mJE4ePChH7+PTDXCJubj4VbRfVx/mWEPs5P2A7ybfSMpve hR4Y2y+tmz4tm4DZR/qZ9lCV3JNknha6SkX1VQ9L/8qyObsfXcw639ACi8KlB8uGwpcJ M0QwnPfbEhET+77XPey+mWwzn3j+nM2zRyctKBqX+nL9OkDM0Qsrp36BKiYv0T8FbcW4 /bCA== X-Gm-Message-State: ACrzQf13cWcTCOVNblRIfuoSxJYC+8TGJNEwXc3gDDbSunzcnFk6gCkk glKtLfQcHwbafdLWfEVx5c/GIV2ncNJcIg== X-Google-Smtp-Source: AMsMyM6HCuZBXjLbcKAb0kZzzGe1I3stP7eXZ/1xyPXUaz+tC7h7/Hsv6m6UXUVnQd6Znq5rkoMefQ== X-Received: by 2002:a63:5322:0:b0:44e:11f7:b414 with SMTP id h34-20020a635322000000b0044e11f7b414mr9471813pgb.226.1664892656512; Tue, 04 Oct 2022 07:10:56 -0700 (PDT) From: Richard Henderson To: qemu-devel@nongnu.org Cc: alex.bennee@linaro.org, =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= Subject: [PATCH v7 01/18] cpu: cache CPUClass in CPUState for hot code paths Date: Tue, 4 Oct 2022 07:10:34 -0700 Message-Id: <20221004141051.110653-2-richard.henderson@linaro.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20221004141051.110653-1-richard.henderson@linaro.org> References: <20221004141051.110653-1-richard.henderson@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" 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::433; envelope-from=richard.henderson@linaro.org; helo=mail-pf1-x433.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 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" X-ZohoMail-DKIM: pass (identity @linaro.org) X-ZM-MESSAGEID: 1664894254715100001 From: Alex Benn=C3=A9e The class cast checkers are quite expensive and always on (unlike the dynamic case who's checks are gated by CONFIG_QOM_CAST_DEBUG). To avoid the overhead of repeatedly checking something which should never change we cache the CPUClass reference for use in the hot code paths. Signed-off-by: Alex Benn=C3=A9e Reviewed-by: Richard Henderson Message-Id: <20220811151413.3350684-3-alex.bennee@linaro.org> Signed-off-by: C=C3=A9dric Le Goater Message-Id: <20220923084803.498337-3-clg@kaod.org> Signed-off-by: Richard Henderson --- include/hw/core/cpu.h | 9 +++++++++ cpu.c | 9 ++++----- 2 files changed, 13 insertions(+), 5 deletions(-) diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h index 500503da13..1a7e1a9380 100644 --- a/include/hw/core/cpu.h +++ b/include/hw/core/cpu.h @@ -51,6 +51,13 @@ typedef int (*WriteCoreDumpFunction)(const void *buf, si= ze_t size, */ #define CPU(obj) ((CPUState *)(obj)) =20 +/* + * The class checkers bring in CPU_GET_CLASS() which is potentially + * expensive given the eventual call to + * object_class_dynamic_cast_assert(). Because of this the CPUState + * has a cached value for the class in cs->cc which is set up in + * cpu_exec_realizefn() for use in hot code paths. + */ typedef struct CPUClass CPUClass; DECLARE_CLASS_CHECKERS(CPUClass, CPU, TYPE_CPU) @@ -317,6 +324,8 @@ struct qemu_work_item; struct CPUState { /*< private >*/ DeviceState parent_obj; + /* cache to avoid expensive CPU_GET_CLASS */ + CPUClass *cc; /*< public >*/ =20 int nr_cores; diff --git a/cpu.c b/cpu.c index 584ac78baf..14365e36f3 100644 --- a/cpu.c +++ b/cpu.c @@ -131,9 +131,8 @@ const VMStateDescription vmstate_cpu_common =3D { =20 void cpu_exec_realizefn(CPUState *cpu, Error **errp) { -#ifndef CONFIG_USER_ONLY - CPUClass *cc =3D CPU_GET_CLASS(cpu); -#endif + /* cache the cpu class for the hotpath */ + cpu->cc =3D CPU_GET_CLASS(cpu); =20 cpu_list_add(cpu); if (!accel_cpu_realizefn(cpu, errp)) { @@ -151,8 +150,8 @@ void cpu_exec_realizefn(CPUState *cpu, Error **errp) if (qdev_get_vmsd(DEVICE(cpu)) =3D=3D NULL) { vmstate_register(NULL, cpu->cpu_index, &vmstate_cpu_common, cpu); } - if (cc->sysemu_ops->legacy_vmsd !=3D NULL) { - vmstate_register(NULL, cpu->cpu_index, cc->sysemu_ops->legacy_vmsd= , cpu); + if (cpu->cc->sysemu_ops->legacy_vmsd !=3D NULL) { + vmstate_register(NULL, cpu->cpu_index, cpu->cc->sysemu_ops->legacy= _vmsd, cpu); } #endif /* CONFIG_USER_ONLY */ } --=20 2.34.1