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 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 4D53FC54E58 for ; Wed, 13 Mar 2024 11:05:04 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rkMPm-00084E-GM; Wed, 13 Mar 2024 07:04:54 -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 1rkMPj-00083r-DO for qemu-devel@nongnu.org; Wed, 13 Mar 2024 07:04:51 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rkMPh-0000U2-4k for qemu-devel@nongnu.org; Wed, 13 Mar 2024 07:04:51 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1710327886; h=from:from:reply-to: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=xTr+njGk3GsFdCw6MLtnpMXfqrNez0s9HGsAL4rnVTo=; b=QAU5OzaQ3mGm8KzXVQhqOYbJhAiAIsdWmfy0j/kVFm5mF2vaduEnNepoYytNNfb1wf5yVT T1Iqpd/xKo6mx4ugVKtxyFVe+OPsCQ2+ZCCbCavUoO+TtImL5k08KjNLmihHpzFHvzgNpg ndt1A6adPtzbCyU1rlXeRRZN6SA2IAI= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-625-33eKy8ZtNnm_B8Yf6Oiy3g-1; Wed, 13 Mar 2024 07:04:44 -0400 X-MC-Unique: 33eKy8ZtNnm_B8Yf6Oiy3g-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id A95DC87280D for ; Wed, 13 Mar 2024 11:04:44 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.47]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 8929F492BC7; Wed, 13 Mar 2024 11:04:43 +0000 (UTC) Date: Wed, 13 Mar 2024 11:04:41 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Anthony Harivel Cc: pbonzini@redhat.com, mtosatti@redhat.com, qemu-devel@nongnu.org, vchundur@redhat.com Subject: Re: [PATCH v3 3/3] Add support for RAPL MSRs in KVM/Qemu Message-ID: References: <20240125072214.318382-1-aharivel@redhat.com> <20240125072214.318382-4-aharivel@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/2.2.12 (2023-09-09) X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.9 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.687, 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: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Wed, Mar 13, 2024 at 11:48:19AM +0100, Anthony Harivel wrote: > Hi Daniel, > > Daniel P. Berrangé, Mar 12, 2024 at 16:49: > > > The point still stands though. NUMA node ID numbers are not > > guaranteed to be the same as socket ID numbers. Very often > > then will be the same (which makes it annoying to test as it > > is easy to not realize the difference), but we can't rely on > > that. > > > > > I'm using functions of libnuma to populate the maxpkgs of the host. > > > I tested this on different Intel CPU with multiple packages and this > > > has always returned the good number of packages. A false positive ? > > > > maxpkgs comes from vmsr_get_max_physical_package() which you're > > reading from sysfs, rather than libnuma. > > > > > So here I'm checking if the thread has run on the package number 'i'. > > > I populate 'numa_node_id' with numa_node_of_cpu(). > > > > > > I did not wanted to reinvent the wheel and the only lib that was talking > > > about "node" was libnuma. > > > > I'm not actually convinced we need to use libnuma at all. IIUC, you're > > just trying to track all CPUs within the same physical socket (package). > > I don't think we need to care about NUMA nodes to do that tracking. > > > > Alright, having a deeper look I'm actually using NUMA for 2 info: > > - How many cpu per Package: this helps me calculate the ratio. > > - To whom package the cpu belongs: to calculate the ratio with the right > package energy counter. > > Without libnuma, I'm bit confused on how to handle this. > > Should I parse /sys/bus/node/devices/node* to know how many packages ? > Should I parse /sys/bus/node/devices/node0/cpu0/topology/core_cpus_list > to handle which cpu belongs to which package ? You don't need to access it via the /node/ hierarchy The canonical path for CPUs would be /sys/devices/system/cpu/cpuNNN/topology The core_cpus_list file is giving you hyper-thread siblings within a core, which I don't think is what you want. If you're after discrete physical packages, then 'package_cpus_list' gives you all CPUs within a physical socket (package) I believe. > Would that be too cumbusome for the user to enter the detail about how > many packages and how many cpu per pakages ? > > i.e: > -kvm,rapl=true,maxpkgs=2,cpupkgs=8,rapl-helper-socket=/path/sock.sock That won't cope with asymmetrical CPU configurations, so I think it is preferrable to read the info from sysfs. With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|