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=-0.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 D280EC433DF for ; Fri, 3 Jul 2020 16:56:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AE2A9208C7 for ; Fri, 3 Jul 2020 16:56:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="j6shZpyy" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726484AbgGCQ4e (ORCPT ); Fri, 3 Jul 2020 12:56:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37380 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726147AbgGCQ4e (ORCPT ); Fri, 3 Jul 2020 12:56:34 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D11E3C061794 for ; Fri, 3 Jul 2020 09:56:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=ABg7NPFpv6+3fRjIjwbJfH0UuoJwtQBPMUCkpYS7fPM=; b=j6shZpyy1OUE9JhmDPF76zXks7 cAIx5QavH4ZH0UFFz7ycfhvbHvVrpLAOkgaOzu7sN0GRQE0GlyaDjP7Wli6wr/Gn7v59kwDWZQsfW 5JUbVXEwGUOL2V/XVmDJ/fm6dkBCQXAV4ZljaqS0btPsispu4YwKjF8v32Z4riyP5/y4uNWQ/Eohm OG3YtJ17U+WnFN/QtYgWnAVKJ+GJZY6lse0CSgqHCzfL80vhnyNqtv/SPiNdEVDVR47I5nBwQcQCF ChUqQYm5CB865YzTERIusgrKxcWQSzaLHSbFpvmTfWJMJPXgeETEZQZDUaCHodFI/ceVHeYVujItC A6TOTdfw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jrOzD-0004Bq-Oa; Fri, 03 Jul 2020 16:56:28 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 37F4C301124; Fri, 3 Jul 2020 18:56:27 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 1AE4920A9E7A6; Fri, 3 Jul 2020 18:56:27 +0200 (CEST) Date: Fri, 3 Jul 2020 18:56:27 +0200 From: Peter Zijlstra To: Uladzislau Rezki Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , Linus Torvalds , GregKroah-Hartmangregkh@linuxfoundation.org Subject: Re: nr_cpu_ids vs AMD 3970x(32 physical CPUs) Message-ID: <20200703165627.GG4781@hirez.programming.kicks-ass.net> References: <20200703155749.GA6255@pc636> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200703155749.GA6255@pc636> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 03, 2020 at 05:57:49PM +0200, Uladzislau Rezki wrote: > Hello, folk. > > I have a system based on AMD 3970x CPUs. It has 32 physical cores > and 64 threads. It seems that "nr_cpu_ids" variable is not correctly > set on latest 5.8-rc3 kernel. Please have a look below on dmesg output: > > > urezki@pc638:~$ sudo dmesg | grep 128 > [ 0.000000] IOAPIC[0]: apic_id 128, version 33, address 0xfec00000, GSI 0-23 > [ 0.000000] smpboot: Allowing 128 CPUs, 64 hotplug CPUs This is your BIOS saying it needs 128 ids, 64 of which are 'empty'. I have a box like that as well, if it bothers you boot with: "possible_cpus=64" or something.