From patchwork Tue Aug 1 10:35:17 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zhao Liu X-Patchwork-Id: 13336458 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0D7C4C0015E for ; Tue, 1 Aug 2023 10:33:57 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qQmgQ-00087C-NM; Tue, 01 Aug 2023 06:32:54 -0400 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 1qQmgP-00084B-CU for qemu-devel@nongnu.org; Tue, 01 Aug 2023 06:32:53 -0400 Received: from [192.55.52.88] (helo=mgamail.intel.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qQmgN-00033E-Hi for qemu-devel@nongnu.org; Tue, 01 Aug 2023 06:32:53 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1690885971; x=1722421971; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=4i3CB21Rs/Ku/zgA8xBOPUikA7feG7BiEa2cJmZGrdw=; b=So7Jtb8baVrtOtTVes7Nnl8FIMY9+1xtN+ZunYxD2F+Yea3S8B++liZ9 TtAZKtCcIOkHLMo58Cd3YcB2AEhM2qj75jhuJPiImtAzfpKnte4moIzv2 SKfmuM/Ax7XZ5GtAhOlziM75wsscVcKQ/HxsCPT/oRATc2xl0/MYIk5KT BUJEb8vs0euY5Ex1bZGfhNwZmzd/aRVyez5Ek/eEl/c+X69aQAxqvCRZw BDrFpHMSaWSW1qgqe7Y3BoDJGde49jVoNC0HFXd3MnZfM2aKBN3REf0n/ gHEbl7gT9PRIl8Mgz/UbRojWFnxg9YUg9q9R1du31rwxBMUV6kI9RwNbX A==; X-IronPort-AV: E=McAfee;i="6600,9927,10788"; a="400211135" X-IronPort-AV: E=Sophos;i="6.01,246,1684825200"; d="scan'208";a="400211135" Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Aug 2023 03:25:26 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10788"; a="731932080" X-IronPort-AV: E=Sophos;i="6.01,246,1684825200"; d="scan'208";a="731932080" Received: from liuzhao-optiplex-7080.sh.intel.com ([10.239.160.28]) by fmsmga007.fm.intel.com with ESMTP; 01 Aug 2023 03:25:23 -0700 From: Zhao Liu To: Eduardo Habkost , Marcel Apfelbaum , =?utf-8?q?Philippe_Mathieu-D?= =?utf-8?q?aud=C3=A9?= , Yanan Wang , "Michael S . Tsirkin" , Richard Henderson , Paolo Bonzini Cc: qemu-devel@nongnu.org, Zhenyu Wang , Xiaoyao Li , Babu Moger , Zhao Liu , Zhuocheng Ding Subject: [PATCH v3 07/17] i386: Introduce module-level cpu topology to CPUX86State Date: Tue, 1 Aug 2023 18:35:17 +0800 Message-Id: <20230801103527.397756-8-zhao1.liu@linux.intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230801103527.397756-1-zhao1.liu@linux.intel.com> References: <20230801103527.397756-1-zhao1.liu@linux.intel.com> MIME-Version: 1.0 X-Host-Lookup-Failed: Reverse DNS lookup failed for 192.55.52.88 (failed) Received-SPF: none client-ip=192.55.52.88; envelope-from=zhao1.liu@linux.intel.com; helo=mgamail.intel.com X-Spam_score_int: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, RDNS_NONE=0.793, SPF_HELO_NONE=0.001, SPF_NONE=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+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: Zhuocheng Ding smp command has the "clusters" parameter but x86 hasn't supported that level. "cluster" is a CPU topology level concept above cores, in which the cores may share some resources (L2 cache or some others like L3 cache tags, depending on the Archs) [1][2]. For x86, the resource shared by cores at the cluster level is mainly the L2 cache. However, using cluster to define x86's L2 cache topology will cause the compatibility problem: Currently, x86 defaults that the L2 cache is shared in one core, which actually implies a default setting "cores per L2 cache is 1" and therefore implicitly defaults to having as many L2 caches as cores. For example (i386 PC machine): -smp 16,sockets=2,dies=2,cores=2,threads=2,maxcpus=16 (*) Considering the topology of the L2 cache, this (*) implicitly means "1 core per L2 cache" and "2 L2 caches per die". If we use cluster to configure L2 cache topology with the new default setting "clusters per L2 cache is 1", the above semantics will change to "2 cores per cluster" and "1 cluster per L2 cache", that is, "2 cores per L2 cache". So the same command (*) will cause changes in the L2 cache topology, further affecting the performance of the virtual machine. Therefore, x86 should only treat cluster as a cpu topology level and avoid using it to change L2 cache by default for compatibility. "cluster" in smp is the CPU topology level which is between "core" and die. For x86, the "cluster" in smp is corresponding to the module level [2], which is above the core level. So use the "module" other than "cluster" in i386 code. And please note that x86 already has a cpu topology level also named "cluster" [3], this level is at the upper level of the package. Here, the cluster in x86 cpu topology is completely different from the "clusters" as the smp parameter. After the module level is introduced, the cluster as the smp parameter will actually refer to the module level of x86. [1]: 864c3b5c32f0 ("hw/core/machine: Introduce CPU cluster topology support") [2]: Yanan's comment about "cluster", https://lists.gnu.org/archive/html/qemu-devel/2023-02/msg04051.html [3]: SDM, vol.3, ch.9, 9.9.1 Hierarchical Mapping of Shared Resources. Signed-off-by: Zhuocheng Ding Co-developed-by: Zhao Liu Signed-off-by: Zhao Liu Acked-by: Michael S. Tsirkin --- Changes since v1: * The background of the introduction of the "cluster" parameter and its exact meaning were revised according to Yanan's explanation. (Yanan) --- hw/i386/x86.c | 1 + target/i386/cpu.c | 1 + target/i386/cpu.h | 5 +++++ 3 files changed, 7 insertions(+) diff --git a/hw/i386/x86.c b/hw/i386/x86.c index a88a126123be..4efc390905ff 100644 --- a/hw/i386/x86.c +++ b/hw/i386/x86.c @@ -309,6 +309,7 @@ void x86_cpu_pre_plug(HotplugHandler *hotplug_dev, init_topo_info(&topo_info, x86ms); env->nr_dies = ms->smp.dies; + env->nr_modules = ms->smp.clusters; /* * If APIC ID is not set, diff --git a/target/i386/cpu.c b/target/i386/cpu.c index fc50bf98c60e..8a9fd5682efc 100644 --- a/target/i386/cpu.c +++ b/target/i386/cpu.c @@ -7606,6 +7606,7 @@ static void x86_cpu_initfn(Object *obj) CPUX86State *env = &cpu->env; env->nr_dies = 1; + env->nr_modules = 1; cpu_set_cpustate_pointers(cpu); object_property_add(obj, "feature-words", "X86CPUFeatureWordInfo", diff --git a/target/i386/cpu.h b/target/i386/cpu.h index 7638128d59cc..5e97d0b76574 100644 --- a/target/i386/cpu.h +++ b/target/i386/cpu.h @@ -1880,6 +1880,11 @@ typedef struct CPUArchState { /* Number of dies within this CPU package. */ unsigned nr_dies; + /* + * Number of modules within this CPU package. + * Module level in x86 cpu topology is corresponding to smp.clusters. + */ + unsigned nr_modules; } CPUX86State; struct kvm_msrs;