From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.remote-ip=198.175.65.11 ARC-Seal: i=2; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=fail; t=1792770932; b=Upc7jIeTg66ijS8Apy/X3rbEph0cyX1BJzG/X5emEfvK6VeE3wKkAQt5L0CjhHfdUYgv ez5JLXKvKb+dAqxbRCD1++SKE1PWUOVqNe89yzWl8074P+dGjuIx7833N39po4CCV6f4t IJy/l1QkimScPAxFA5RtrVmElGrXbYV49AxeXiXtOTdM9m5DwrMwf3hEVFelo3TvhdAaZ MVk779durb/8MsFwL8TJ6g9j2TjXL/WuQyXqzfOadduoUyLEjbkpcFcekPVpIbgiLo8Cv IIMuUBN3tdYWHvR8yYhxtsskmu1F9/khwgtDiKi97bHFgvVK3WKF5HeY5cFF3bQLEfQ== ARC-Message-Signature: i=2; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792770932; h=DMARC-Filter:DKIM-Signature:X-CSE-ConnectionGUID:X-CSE-MsgGUID: X-IronPort-AV:X-IronPort-AV:Received:X-CSE-ConnectionGUID: X-CSE-MsgGUID:X-ExtLoop1:X-IronPort-AV:Received:Received:Received: Received:Received:Received:Date:From:To:CC:Subject:Message-ID: References:Content-Type:Content-Disposition:In-Reply-To: X-ClientProxiedBy:MIME-Version:X-MS-PublicTrafficType: X-MS-TrafficTypeDiagnostic:X-MS-Office365-Filtering-Correlation-Id: X-MS-Exchange-SenderADCheck:X-MS-Exchange-AntiSpam-Relay: X-Microsoft-Antispam:X-Microsoft-Antispam-Message-Info: X-Forefront-Antispam-Report: X-MS-Exchange-AntiSpam-MessageData-ChunkCount: X-MS-Exchange-AntiSpam-MessageData-0:X-Exchange-RoutingPolicyChecked: X-MS-Exchange-CrossTenant-Network-Message-Id: X-MS-Exchange-CrossTenant-AuthSource:X-MS-Exchange-CrossTenant-AuthAs: X-MS-Exchange-CrossTenant-OriginalArrivalTime: X-MS-Exchange-CrossTenant-FromEntityHeader: X-MS-Exchange-CrossTenant-Id:X-MS-Exchange-CrossTenant-MailboxType: X-MS-Exchange-CrossTenant-UserPrincipalName: X-MS-Exchange-Transport-CrossTenantHeadersStamped:X-OriginatorOrg; bh=Io4JDRmv/7LAqfN2ndyYDaeCe7lZAtDjXoHXyixXjCA=; b=vpdb2jHsyPXE7wjkllyS6vWsuuiw+uLp3u4sY7x0M7/sGYAC1z0EF8j9z0uSBi8bKEG8 BSWbp4+sA+/A5/WHZS9T1jGO0e2gjMCVyYXgCA1kmyEQ8wm9nbUuJgB1ToCpfVlG4+Ih/ gVEcVDqcUFWDoSKDlz5I8+AwSB5OVO0LAi+TbzGoOGY4XdE3HuxKaLsCUxnb/wca0/A1u kpFp42j8AytlNhlQpe4dV9wdtv63000Zc4CVHFxp6AU2nFNQ8rRd2eNE84yZBnEPIbhQQ pPKJprfem6DdNNf4BXhleNHbuzSvBMdHoKhc2abnrVenHuaim5gIUi/YfJorsbjJS9A== ARC-Authentication-Results: i=2; smtp.subspace.kernel.org; dmarc=pass header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass header.d=intel.com header.i=@intel.com header.a=rsa-sha256 header.s=Intel header.b=C3VD53kB; arc=fail smtp.remote-ip=198.175.65.11 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.11]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 41E76606A31B for ; Fri, 23 Oct 2026 15:55:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 41E76606A31B Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=intel.com header.i=@intel.com header.a=rsa-sha256 header.s=Intel header.b=C3VD53kB DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1792770931; x=1824306931; h=date:from:to:cc:subject:message-id:references: in-reply-to:mime-version; bh=Jj9Zfha1o7UziFCyOhXw9gpJmygPmhKS/GAjs3eA6Nw=; b=C3VD53kBT4/GH19U0fGuWtiRQ29fvx7BfmSIdxtZg881WlyiLkpb9ryY bv44ujAX3S4Aea9Fno5seK/kbpEPUsgS23h+dogw2KIyiluSwGGlSD2Sk /mJfyRctcCART0a2H9R/XMOYIfpO/55qUky81suAdfcDQGhrV8K79OPYz 38wK2oFMUoBny4jAWgfGlBzHtKg+VR0TRDZIYi7DZfwFDiMiWNbepDva2 i5KwqYIju6hAL5rIBgKNsMbY9c5GBcEOtu6TBeGYsqR6eHNRk4vxKu2nq OnVU/+Qmv9d4m64clxl+hOxIz3ZO8VhY3xfdq9eWB0R3QYklBNb/HwkF1 Q==; X-CSE-ConnectionGUID: g1GDICULT2iWwPk2qIIgyQ== X-CSE-MsgGUID: XGQJXB2aSOiVMOhluaNTiQ== X-IronPort-AV: E=McAfee;i="6800,10657,11944"; a="1420388" X-IronPort-AV: E=Sophos;i="6.27,174,1787036400"; d="scan'208";a="1420388" Received: from orviesa008.jf.intel.com ([10.64.159.148]) by orvoesa103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Oct 2026 08:55:31 -0700 X-CSE-ConnectionGUID: YDBE95lJROqKVcHKznGNpw== X-CSE-MsgGUID: cVbGn3lARoCrPNaAsJe5Cw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.27,174,1787036400"; d="scan'208";a="3556987" Received: from fmsmsx902.amr.corp.intel.com ([10.18.126.91]) by orviesa008.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Oct 2026 08:55:30 -0700 Received: from FMSMSX901.amr.corp.intel.com (10.18.126.90) by fmsmsx902.amr.corp.intel.com (10.18.126.91) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.49; Fri, 23 Oct 2026 08:55:29 -0700 Received: from fmsedg901.ED.cps.intel.com (10.1.192.143) by FMSMSX901.amr.corp.intel.com (10.18.126.90) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.49 via Frontend Transport; Fri, 23 Oct 2026 08:55:29 -0700 Received: from PH7PR06CU001.outbound.protection.outlook.com (52.101.201.68) by edgegateway.intel.com (192.55.55.81) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.49; Fri, 23 Oct 2026 08:55:28 -0700 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=qhcoID/M31grPjXXUpHOWQK5PkeCxtigZpLpUhTLxaP6HaDH0JOGI1mUhkmiWJzclZRI2wE+LHXAPHIXkYL87KXQow0dGq/u6HHka7ygaeRtPA2rAVhaKOGPVQbHYrtS9NsMVz5oATmN4nHldBWo1EJjlYS56qnOQGS+VI5u5E3VtvbwpVpZ6bhKe3EX/f3m56do49KTh4S3uOBA/VlaIVW64vgTnNSAzLvDFZ8uLLScpvrJdbTotakJk0UqloKJfQibDoaLM/YyG4OVcNNfByr12uYWn1+DM/CMJXWdGgPQ2n0CqiKW+jQoK3BNMSVrp14Ip/MfeIiEiHE95553Vg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=Io4JDRmv/7LAqfN2ndyYDaeCe7lZAtDjXoHXyixXjCA=; b=QPImRHye09wDoR+tOdx5k+q9iMQBdWpDPRMXd2Ls08hJNPsY9iti0/plGnUAnajny8jJ39FEcYFsHOqIuBd4Xg04nsOlgKOUE0+N44MOdjPrum8SCr18mhfk4mTC2YF2AEPcsS7uRjXUxsKXpcoCuOih/1ML/YIxmojhv/YMrjH0fBuGteNtyyyk73bNHEEmT1QJOYmj+5BnGUCWnM7f6XvOXjmAfA1AwcVCptqysmGt6UwI3VKhYFrF5xsuSy8nHH+bEXNVFPffWIk2AGsIymD/rnPe9hETyu/aplUO4A8QOmI4+DpqTQ6m4jlInYYzZGzApXw7lWthRtaD3qFFIA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=intel.com; dmarc=pass action=none header.from=intel.com; dkim=pass header.d=intel.com; arc=none Authentication-Results: mx.microsoft.com 1; dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=intel.com; Received: from DM4PR11MB6020.namprd11.prod.outlook.com (2603:10b6:8:61::19) by PH0PR11MB5206.namprd11.prod.outlook.com (2603:10b6:510:3f::18) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.546.17; Fri, 23 Oct 2026 15:55:26 +0000 Received: from DM4PR11MB6020.namprd11.prod.outlook.com ([fe80::3058:1480:e4ac:5765]) by DM4PR11MB6020.namprd11.prod.outlook.com ([fe80::3058:1480:e4ac:5765%3]) with mapi id 15.21.0546.012; Fri, 23 Oct 2026 15:55:26 +0000 Date: Fri, 23 Oct 2026 23:42:32 +0800 From: Chen Yu To: Shrikanth Hegde CC: , , , , , , , , , , , , Subject: Re: [PATCH v2 1/4] powerpc/topology: Introduce llc_override kernel parameter Message-ID: References: <20261023131646.2907938-1-sshegde@linux.ibm.com> <20261023131646.2907938-2-sshegde@linux.ibm.com> Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20261023131646.2907938-2-sshegde@linux.ibm.com> X-ClientProxiedBy: SI2P153CA0002.APCP153.PROD.OUTLOOK.COM (2603:1096:4:140::16) To DM4PR11MB6020.namprd11.prod.outlook.com (2603:10b6:8:61::19) X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DM4PR11MB6020:EE_|PH0PR11MB5206:EE_ X-MS-Office365-Filtering-Correlation-Id: cca7823e-a78f-4a51-3ec3-08df311e0df1 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|23010399003|366016|376014|7416014|1800799024|261009223027099003|261021121427099003|56012099006|10067099003|3023799007|22082099003|18002099003|4143699003|11063799006|261022105027099003|261022075727099003; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:DM4PR11MB6020.namprd11.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(23010399003)(366016)(376014)(7416014)(1800799024)(261009223027099003)(261021121427099003)(56012099006)(10067099003)(3023799007)(22082099003)(18002099003)(4143699003)(11063799006)(261022105027099003)(261022075727099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?iiVVupJmShl6eUdrc5rMO3/lef6VKHOg/VxZq/LBKW822QV+n965KluwlUOQ?= =?us-ascii?Q?mk3lC/DN721SsTE/g9wGRykHT8W99Xnwy+CZpokjx1PvmL0HkGA/h2ryL1G6?= =?us-ascii?Q?K6qAlH9qIihbMaE48PD/YhFcgd4JZIPsM43aUNbLUN0q2N3KMzx4EsAF7imv?= =?us-ascii?Q?cRGpgCMVRGibC+GfoMofZdWviY/8Ajy6xASxZmqrAoQHQjBXo2NOGy7UDWlA?= =?us-ascii?Q?+GO3FIM3a0MR0IiXBDqtj6dexHfCx9gLFrQS7oOJoONgCbG/f3XCoq54uQip?= =?us-ascii?Q?9G3MdPHGvdWhmfm61Cme4VKMTTc7eRGZBU4wfQpZ89o1u19ucpk/TwzueFfR?= =?us-ascii?Q?+t85cbF6puLSaMw4r10EiHyirrw/TEpxhWzsovtImHeCuVtmf4pQ+68FEtZM?= =?us-ascii?Q?u9zmmSXhL7Ywx/2NNylFJCdRKCaMyO+K0Kg+QzRKzZ5ZfLZQfGUhsKscmN93?= =?us-ascii?Q?DtP2RL/Sdr3XUravZz7krRx5Roquu6sZvpxuyZp+62eds3cPqlFQzDn10Fdq?= =?us-ascii?Q?LuBQnrZFErgQQJtJMj6hf9RwlDsVkmvQljVgoiyJxi0VAPQNXq/GbvHRdQ+x?= =?us-ascii?Q?aB7vhVmAcwOpskjCAQXmc9rdCMdTX8SAlSHjA5cSSn5aLBw3IyUuF0swDlQk?= =?us-ascii?Q?xzKQIon35RQYBbIdXfBbWyiR2eBBpNL7QYF7IcZyqjMPWZ9F/8EDw6y+d370?= =?us-ascii?Q?3DUg3kdCdAs8qkopdIAloFQpnJ7jClIZf3/W4+HTxV3famCqRy+ECq3TsqUF?= =?us-ascii?Q?jzxwqhJtRr5jiUeLQIMKOq0+P0m9haL/ZsMq2uuS2+xKbKzAHB2PyQ6OYWhe?= =?us-ascii?Q?U52oi0kSIxLWQw3+r5Ic75jnk77maakDTRY2uTAkl/11AHZc5XLCKAn4PLF7?= =?us-ascii?Q?M6wBaawX4XN6qpvqUe7TJvA9rHeowAbXgBHantWjYDwAzkBMUOEiyxUQJJx6?= =?us-ascii?Q?qMwjYeocIcB0nO2YlG7jMJsw8R6SS0mr3zjS7goyofKDnTsIbYE75PauZWFe?= =?us-ascii?Q?a+Y5vgc2GpUJXDaMV50/Mlm5TLKbmcbJJWih9tWnNN89IzDNUGjN1+PjrZak?= =?us-ascii?Q?k/Cy2MiAEpWqBpKOVHCt8bC7ajXtEhWAMFHl3t6oSlV8Af9Jqbui6GIY60Gj?= =?us-ascii?Q?wMMWM9F4UTJv5UZyssCmIGGmcRH+gij6Jvq1frQkfraJnksHPQk6+gFiKSaG?= =?us-ascii?Q?PH7OgdG/2wS6TmbzxlqHKb6rO7qZLnzr31owStr4JLOIIBaLhB+N9PSykbZa?= =?us-ascii?Q?hI6gxUbNccuudWLGAw4U0KT7V7eKP3b5FYrx3VAhO+v/r8T0205cW90MJDpr?= =?us-ascii?Q?uGFmfJNzJUnQZEO90S859qRR4uqzevJiAGhCUopfLZ5LLMlqELWQlGxjJXDD?= =?us-ascii?Q?ZajT4QXP+O2pvO9limtBx3fU8X3tPxfaI3NUNXT02Ht3nq+U+seawKHdy17C?= =?us-ascii?Q?KvAIJ3YdXTBZuMsBN0tt6NNaxH1/rxTpGkMlLHCbYbupqmgwFTTq5Gk5rxWu?= =?us-ascii?Q?bzsOtduzQfCnnyD6UG30J4e4Cs/Tk75QVK0lecK7qxmMohUXS+dK6OC8vDPJ?= =?us-ascii?Q?agW3/hVQJ/CKWfrdLTAqvRQzHXs6vNy6//BEcYCrMbpFpKu3sceJd6Z12go/?= =?us-ascii?Q?Zomw0DKAyoyzd1ynoMMLc3b+67+BgcQLWErV3sGKk4wLWN4kKbNms5md5GqV?= =?us-ascii?Q?g5Iibt73BRuzZ30oBt9XIxsNvQyT+cdRF6huxh4TNysG4vhlM+ah/JGhigXl?= =?us-ascii?Q?tBTgIF34rQ=3D=3D?= X-Exchange-RoutingPolicyChecked: 4lZ6IeSO+j0o3RCdrO8bS9TgznsH2iKsqJU54yApd7a0wKuOqfvtb1kKplIE/HTqKgqdqfyFm7jsZZryf36cG9xzpFRm8zrMOVajHGJRegg7/tOoe4mn8PMoPqKLa7GgJRRS2QdhlXPoKCqu7eALAUAKS9t3tjSaRJLBSJyKg5Ly2Xlq5voGE9y3DZYYVpOlarWK7UHp+bEioWXM83NDR9dfFGmmJoJGIt3uuK2nhjkbI2es/GkebSp0EJpvoAwPJgzw74wXMFxsZWOgN134a/orTX0aqKTp7uv6g1Yt2gGaLQ3o96JniXaMDpYHRLSTkOrtKvCeEwjzYa2LexQliQ== X-MS-Exchange-CrossTenant-Network-Message-Id: cca7823e-a78f-4a51-3ec3-08df311e0df1 X-MS-Exchange-CrossTenant-AuthSource: DM4PR11MB6020.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 23 Oct 2026 15:55:26.5967 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: bI9Eqkki/XmBpGHVmyRtJKwSMMtIgB+9Mr19nZd5XNH03lItphPShh0D6zJdHh5IO4HUTVAAjMJ/v672UMiohw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH0PR11MB5206 X-OriginatorOrg: intel.com Hi Shrikanth, On Fri, Oct 23, 2026 at 06:46:43PM +0530, Shrikanth Hegde wrote: [ ... ] > --- > arch/powerpc/kernel/smp.c | 23 +++++++++++++++++++++++ > 1 file changed, 23 insertions(+) > > diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c > index 6a5a5469aaae..6b1201ea3572 100644 > --- a/arch/powerpc/kernel/smp.c > +++ b/arch/powerpc/kernel/smp.c > @@ -1059,6 +1059,29 @@ static bool has_coregroup_support(void) > return coregroup_enabled; > } > > +enum llc_override_values { > + LLC_OVERRIDE_MC = 1, > + LLC_OVERRIDE_PKG = 2, > +}; > + > +static int llc_override; > + > +static int __init set_llc_override(char *str) > +{ > + if (!strcasecmp(str, "mc") && has_coregroup_support()) > + WRITE_ONCE(llc_override, LLC_OVERRIDE_MC); There is only 1 booting CPU at the moment, maybe WRITE_ONCE() is not needed. > + else if (!strcasecmp(str, "pkg")) > + WRITE_ONCE(llc_override, LLC_OVERRIDE_PKG); > + else { > + pr_warn("Unsupported llc_override=%s\n", str); > + return 1; > + } > + > + pr_info("llc_override set at domain: %s\n", str); > + return 1; > +} > +__setup("llc_override=", set_llc_override); > + > static int __init init_big_cores(void) > { > int cpu; On PowerPC, it seems that get_effective_llc_bytes() always returns 0, which makes exceed_llc_capacity() return true, so cache-aware scheduling is disabled on PowerPC. We might need to provide an arch_llc_bytes() that is adjusted based on llc_override - sometimes calculate the sum of L2 across several cores. thanks, Chenyu