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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 DE779C2D0DB for ; Sat, 25 Jan 2020 19:41:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9D57B2071E for ; Sat, 25 Jan 2020 19:41:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="UobfgHjS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727430AbgAYTlw (ORCPT ); Sat, 25 Jan 2020 14:41:52 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:29771 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726612AbgAYTlw (ORCPT ); Sat, 25 Jan 2020 14:41:52 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1579981310; 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=AgpWBVZ2Zmngb4zlRI3WuIHZKM7LDWwyVepAeoXIIIw=; b=UobfgHjSGNTtIUqscxGN8TjnsxspaL94gUHshVjkPCwfPbOKBZ8SUam0fsMxfMVU8+HH6l /q+/USV+aO4eWam0aTX7ncXzbykl1eDUjuDvcVQBBoAC9rFSeqVLb0fMUw2owT9I7Q3QLv btWRP/moFjN6MisvnnUZ/RqQGiIIFCw= 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-214-9INydv1jPCy2zEZg_D8bFQ-1; Sat, 25 Jan 2020 14:41:45 -0500 X-MC-Unique: 9INydv1jPCy2zEZg_D8bFQ-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 22CD91800D48; Sat, 25 Jan 2020 19:41:42 +0000 (UTC) Received: from llong.remote.csb (ovpn-121-36.rdu2.redhat.com [10.10.121.36]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0F9172718F; Sat, 25 Jan 2020 19:41:37 +0000 (UTC) Subject: Re: [PATCH v9 0/5] Add NUMA-awareness to qspinlock To: paulmck@kernel.org Cc: Alex Kogan , linux@armlinux.org.uk, Peter Zijlstra , Ingo Molnar , Will Deacon , Arnd Bergmann , linux-arch@vger.kernel.org, linux-arm-kernel , linux-kernel@vger.kernel.org, tglx@linutronix.de, bp@alien8.de, hpa@zytor.com, x86@kernel.org, guohanjun@huawei.com, jglauber@marvell.com, dave.dice@oracle.com, steven.sistare@oracle.com, daniel.m.jordan@oracle.com References: <20200115035920.54451-1-alex.kogan@oracle.com> <20200124222434.GA7196@paulmck-ThinkPad-P72> <6AAE7FC6-F5DE-4067-8BC4-77F27948CD09@oracle.com> <20200125005713.GZ2935@paulmck-ThinkPad-P72> <02defadb-217d-7803-88a1-ec72a37eda28@redhat.com> <20200125045844.GC2935@paulmck-ThinkPad-P72> From: Waiman Long Organization: Red Hat Message-ID: <967f99ee-b781-43f4-d8ba-af83786c429c@redhat.com> Date: Sat, 25 Jan 2020 14:41:39 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: <20200125045844.GC2935@paulmck-ThinkPad-P72> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 1/24/20 11:58 PM, Paul E. McKenney wrote: > On Fri, Jan 24, 2020 at 09:17:05PM -0500, Waiman Long wrote: >> On 1/24/20 8:59 PM, Waiman Long wrote: >>>> You called it! I will play with QEMU's -numa argument to see if I can get >>>> CNA to run for me. Please accept my apologies for the false alarm. >>>> >>>> Thanx, Paul >>>> >>> CNA is not currently supported in a VM guest simply because the numa >>> information is not reliable. You will have to run it on baremetal to >>> test it. Sorry for that. >> Correction. There is a command line option to force CNA lock to be used >> in a VM. Use the "numa_spinlock=on" boot command line parameter. > As I understand it, I need to use a series of -numa arguments to qemu > combined with the numa_spinlock=on (or =1) on the kernel command line. > If the kernel thinks that there is only one NUMA node, it appears to > avoid doing CNA. > > Correct? > > Thanx, Paul > In auto-detection mode (the default), CNA will only be turned on when paravirt qspinlock is not enabled first and there are at least 2 numa nodes. The "numa_spinlock=on" option will force it on even when both of the above conditions are false. Cheers, Longman