From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3A531C2B9F4 for ; Mon, 28 Jun 2021 11:35:47 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id E441E61C70 for ; Mon, 28 Jun 2021 11:35:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E441E61C70 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:60190 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lxpYH-0000Gj-Sx for qemu-devel@archiver.kernel.org; Mon, 28 Jun 2021 07:35:45 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:43330) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lxpTs-0002eY-7W for qemu-devel@nongnu.org; Mon, 28 Jun 2021 07:31:13 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:31959) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lxpTn-0000rq-Db for qemu-devel@nongnu.org; Mon, 28 Jun 2021 07:31:11 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1624879866; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=oxkQw40azd4u6tRPeYCKlzg1aWPX8REFv+DGaGQ6quA=; b=JblJEqHKubbhS4KxUXSxfCh2pKk/nXnOC92zIsjcIxnNqpO/Q/ubF6SKxYBFUfIPWZEBjo cRZrUHoaj7Ur2E2pxxCugJ7dIOrbuiBftMaz03NqHAL98vgwmls1/37iimVL6CQXhVrnPI cmoTQUWkILJRj/QoqThHg1g8a1O8G64= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-476-oHCvQ2oWMg64ZvCGwlWAuQ-1; Mon, 28 Jun 2021 07:31:03 -0400 X-MC-Unique: oHCvQ2oWMg64ZvCGwlWAuQ-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 27FCDBBEE4; Mon, 28 Jun 2021 11:31:02 +0000 (UTC) Received: from localhost.localdomain.com (ovpn-115-35.ams2.redhat.com [10.36.115.35]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0BBA060E3A; Mon, 28 Jun 2021 11:30:59 +0000 (UTC) From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= To: qemu-devel@nongnu.org Subject: [PATCH 4/4] qemu-options: rewrite help for -smp options Date: Mon, 28 Jun 2021 12:30:47 +0100 Message-Id: <20210628113047.462498-5-berrange@redhat.com> In-Reply-To: <20210628113047.462498-1-berrange@redhat.com> References: <20210628113047.462498-1-berrange@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=berrange@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.375, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, 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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Andrew Jones , =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= , Eduardo Habkost , Richard Henderson , "wangyanan \(Y\)" , Paolo Bonzini , Igor Mammedov Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" The -smp option help is peculiarly specific about mentioning the CPU upper limits, but these are wrong. The "PC" target has varying max CPU counts depending on the machine type picked. Notes about guest OS limits are inappropriate for QEMU docs. There are way too many machine types for it to be practical to mention actual limits, and some limits are even modified by downstream distribtions. Thus it is better to remove the specific limits entirely. The CPU topology reporting is also not neccessarily specific to the PC platform and descriptions around the rules of usage are somewhat terse. Expand this information with some examples to show effects of defaulting. Signed-off-by: Daniel P. Berrangé --- qemu-options.hx | 29 +++++++++++++++++++++-------- 1 file changed, 21 insertions(+), 8 deletions(-) diff --git a/qemu-options.hx b/qemu-options.hx index 5871df7291..0021e9ec7b 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -207,14 +207,27 @@ DEF("smp", HAS_ARG, QEMU_OPTION_smp, QEMU_ARCH_ALL) SRST ``-smp [[cpus=]n][,maxcpus=maxcpus][,sockets=sockets][,dies=dies][,cores=cores][,threads=threads]`` - Simulate an SMP system with n CPUs. On the PC target, up to 255 CPUs - are supported. On Sparc32 target, Linux limits the number of usable - CPUs to 4. For the PC target, the number of cores per die, the - number of threads per cores, the number of dies per packages and the - total number of sockets can be specified. Missing values will be - computed. If any on the three values is given, the total number of - CPUs n can be omitted. maxcpus specifies the maximum number of - hotpluggable CPUs. + Simulate an SMP system with '\ ``n``\ ' CPUs initially present on + the machine type board. On boards supporting CPU hotplug, the optional + '\ ``maxcpus``\ ' parameter can be set to enable further CPUs to be + added at runtime. If omitted the maximum number of CPUs will be + set to match the initial CPU count. Both parameters are subject to + an upper limit that is determined by the specific machine type chosen. + + To control reporting of CPU topology information, the number of sockets, + dies per socket, cores per die, and threads per core can be specified. + The sum `` sockets * cores * dies * threads `` must be equal to the + maximum CPU count. CPU targets may only support a subset of the topology + parameters. Where a CPU target does not support use of a particular + topology parameter, its value should be assumed to be 1 for the purpose + of computing the CPU maximum count. + + Either the initial CPU count, or at least one of the topology parameters + must be specified. Values for any omitted parameters will be computed + from those which are given. Historically preference was given to the + coarsest topology parameters when computing missing values (ie sockets + preferred over cores, which were preferred over threads), however, this + behaviour is considered liable to change. ERST DEF("numa", HAS_ARG, QEMU_OPTION_numa, -- 2.31.1