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.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (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 1F367CE7AFE for ; Fri, 6 Sep 2024 10:42:48 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [127.0.0.1]) by lists.ozlabs.org (Postfix) with ESMTP id 4X0Xqq3JvFz304B; Fri, 6 Sep 2024 20:42:47 +1000 (AEST) Authentication-Results: lists.ozlabs.org; arc=none smtp.remote-ip=217.140.110.172 ARC-Seal: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1725606440; cv=none; b=eLAQ2e4L3zkfijAHWRWSL8J+8Z4fSgnVWwtqDFU7bL5+7bIDxmv9Rt/H2STFkOqot7AfKay8zdx5oZmfUL2LEohsVZo2qU1PgJLdIRA6oYhXGAwb91AV6tZEPVSoiPAbHSyKM0QX+WEb8wLxRGS5LXP32ze6SuFqZD9Icai4GxxmM1/NRRaXdTtrt45V7138Lzcy4syvR5RaQshzjH5wehfmc9fYeJOSK8qcrBm4mvBh5OBJnEVBfWwri9sATagQ0hW+gFRBxY6pEn2sgmTZnP1rNXVFi4OPBDXh/B5aTZ6oKg8S/l46ISL6ZaIDVX3dsQHPmUdYJUaub/3SWtq44Q== ARC-Message-Signature: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1725606440; c=relaxed/relaxed; bh=JzHuzwYv1A4WZNysYS65N8PwpinTo4zkrx7lnPByC8M=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=mA5Xc5aWN7ZVaY3+sNUk39Na0rsxjAH+StR34HV3O74i4U5qJuBhts4Un7Q/UckvcoWYy4v4lI+k7sfxuVPcnWqdvu1hzFdgWE8n1qZnUByJ3xOZJr+TwRiTfzvcs+4x83C7b1Vp84yg0aYVwQQihQEtf02gcyQFPxMaAd9HIfVq058Andioc2TUBoqJFa9uh/2CpvAcRRsYA063LdL3RIuZm1JQ4/LGCnhLvdHCwO0MaPWkd+6AgHP3mel4iy8vbKfuv2rtMU24ztM0MVwvu4Xc48KKZeXlLnicrQHDW7SaBr6HLj9xqf8SMWrn8pV3tg8IfOTbMLTBuvQs/MmXGg== ARC-Authentication-Results: i=1; lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass (client-ip=217.140.110.172; helo=foss.arm.com; envelope-from=morten.rasmussen@arm.com; receiver=lists.ozlabs.org) smtp.mailfrom=arm.com Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=arm.com (client-ip=217.140.110.172; helo=foss.arm.com; envelope-from=morten.rasmussen@arm.com; receiver=lists.ozlabs.org) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lists.ozlabs.org (Postfix) with ESMTP id 4X0S3D0sTtz301Y for ; Fri, 6 Sep 2024 17:07:17 +1000 (AEST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 69D0EFEC; Fri, 6 Sep 2024 00:07:12 -0700 (PDT) Received: from R5WKVNH4JW (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4D6703F66E; Fri, 6 Sep 2024 00:06:41 -0700 (PDT) Date: Fri, 6 Sep 2024 09:06:33 +0200 From: Morten Rasmussen To: Yicong Yang Cc: Pierre Gondois , yangyicong@hisilicon.com, linuxppc-dev@lists.ozlabs.org, bp@alien8.de, dave.hansen@linux.intel.com, mingo@redhat.com, linux-arm-kernel@lists.infradead.org, mpe@ellerman.id.au, peterz@infradead.org, tglx@linutronix.de, sudeep.holla@arm.com, will@kernel.org, catalin.marinas@arm.com, x86@kernel.org, linux-kernel@vger.kernel.org, dietmar.eggemann@arm.com, gregkh@linuxfoundation.org, rafael@kernel.org, jonathan.cameron@huawei.com, prime.zeng@hisilicon.com, linuxarm@huawei.com, xuwei5@huawei.com, guohanjun@huawei.com Subject: Re: [PATCH v5 3/4] arm64: topology: Support SMT control on ACPI based system Message-ID: References: <20240806085320.63514-1-yangyicong@huawei.com> <20240806085320.63514-4-yangyicong@huawei.com> <00e6110a-462a-c117-0292-e88b57d27a05@huawei.com> <3947cb79-3199-4cd6-b784-51a245084581@arm.com> <1a7b5ac7-f040-672f-07a0-d7f3dc170c88@huawei.com> <6c05e39c-41f3-451c-b119-7b8662c1ceee@arm.com> <7f722af2-2969-aae5-1fb5-68d353eb95b9@huawei.com> <277bd093-422b-4301-92a3-d0a58eb41af5@arm.com> <10082e64-b00a-a30b-b9c5-1401a54f6717@huawei.com> X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Post: List-Subscribe: , , List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <10082e64-b00a-a30b-b9c5-1401a54f6717@huawei.com> Hi Yicong, On Thu, Sep 05, 2024 at 08:02:20PM +0800, Yicong Yang wrote: > On 2024/9/5 16:34, Pierre Gondois wrote: > > Hello Yicong, > > > > If a platform has CPUs with: > > - 1 thread > > - X (!= 1) threads > > Then I think that the asymmetry is not detected > > Ah ok, I only handle the case where there are several thread numbers except no SMT CPUs in the > system. For this case I was thinking we don't need to handle this since there's only one kind > of SMT core in the system, control should works fine for the SMT CPU clusters and we may not > care about the CPUs with no SMT. > > Below code should handle the case if we initialize the max_smt_thread_num to 0. I also > reword the warning messages to match the fact. For heterogeneous SMT topology we still > support control SMT by on/off toggle but not fully support setting the thread number. > > int max_smt_thread_num = 0; > [...] > /* > * This should be a short loop depending on the number of heterogeneous > * CPU clusters. Typically on a homogeneous system there's only one > * entry in the XArray. > */ > xa_for_each(&hetero_cpu, hetero_id, entry) { > /* > * If max_smt_thread_num has been initialized and doesn't match > * the thread number of this entry, then the system has > * heterogeneous SMT topology. > */ > if (entry->thread_num != max_smt_thread_num && max_smt_thread_num) > pr_warn_once("Heterogeneous SMT topology is partly supported by SMT control\n"); What does 'partly supported' mean here? If the SMT control doesn't work as intended for this topology, I don't think it should be enabled for it. Morten