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Mon, 11 Jan 2021 17:57:44 +0000 Date: Mon, 11 Jan 2021 09:57:41 -0800 From: Vanshidhar Konda To: Will Deacon Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, catalin.marinas@arm.com, patches@amperecomputing.com Subject: Re: [PATCH] arm64: Kconfig: Increase NR_CPUS default to 512 Message-ID: <20210111175741.ldifmv7uhdekbq5d@con01sys-r111.scc-lab.amperecomputing.com> References: <20210110053615.3594358-1-vanshikonda@os.amperecomputing.com> <20210111105636.GA7071@willie-the-truck> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20210111105636.GA7071@willie-the-truck> X-Originating-IP: [4.28.12.214] X-ClientProxiedBy: CY4PR22CA0069.namprd22.prod.outlook.com (2603:10b6:903:ae::31) To BYAPR01MB4293.prod.exchangelabs.com (2603:10b6:a03:12::18) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from localhost (4.28.12.214) by CY4PR22CA0069.namprd22.prod.outlook.com (2603:10b6:903:ae::31) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3742.6 via Frontend Transport; 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X-MS-Exchange-AntiSpam-MessageData: =?us-ascii?Q?bmrTT66BbUgxkhVVWRIO2A4bJEW4WjqCxzm1DtQIoIEEz7kBYMVcwhDpRyZl?= =?us-ascii?Q?9R3/A0XwaGmHgkO0kY0nx9QTxwXb79MMNw1IW8kBr8zfNRs1OXm2I6Bon7t/?= =?us-ascii?Q?IU7jTagJQBfJ90RNTE0QLOVFRkgZPgP0of8wG2Yae1ulM0u/7nd5bszkIwq+?= =?us-ascii?Q?ggHWGUtHkMt5S51q4fpusL9MjMQj5li2YnxYLOIuibV+Oe5PzHAFknjGDMVs?= =?us-ascii?Q?OsfQnX7cYT5xZbdAS2XDuCZ6a1L0r8I6VlKffbxVBuY8oIh/YXA+UT0JGQ/6?= =?us-ascii?Q?ilBeBkYZg8tNJK0lUC8Rk4pUwSo4VOCKv8JdJMh+icGihOUA8Q9/wvwFAlW3?= =?us-ascii?Q?XXswuCVZAMFpbNYizPtSrOw432ddpP4QZlHei9xCaFhUHZEIjrZaoc9y3H6M?= =?us-ascii?Q?avpHpoT7sjOPqP3MDUo97piphpybKnXZEIw1OMzhu7FHhQpMvRZ95S8GlwJj?= =?us-ascii?Q?kBZ+NGwktNtGTUhzo/wGJ8CCII12ax5fBqpuR3N89eQMhTiCN3k6B+BJwUCD?= =?us-ascii?Q?aJOnjFZdK/xdBjCCdmVUGsoCBE0T5aOd2PkqZBFtSsNbBAzNnaoc7jHLzv5T?= =?us-ascii?Q?bLq6G4KRzkODamOvHvCZ1eRmnED9uTVgr6+T9XQLryL5QWzyKeY8XPWItNc1?= =?us-ascii?Q?zPklF3D9aQQ2QMm7AnhFIpBWXsWR8tccnjhiLIJGW8fI0ZBlKo/CoPy+mZ9M?= =?us-ascii?Q?u2JSKJtiYyMIaZNIUbMD4inPux61dnCEa92av8uNnfR00wkt8ikX8H+SnZI4?= =?us-ascii?Q?KPRbx2mMf3ZkgUmRQyFsDOFG4twun55ZWr1x3O+KjhlB5sy1gho1yzk4FQGe?= =?us-ascii?Q?s1oLIBw6pExPcMxMMGE9NTR7GmH2Z+xjN4prZZ8pvZ3+9MbKOXkDo20kXc2p?= =?us-ascii?Q?knIhqwiV5V2SHSpXoffyRttoTy4ztpkT90bEry0q9djDLlQQu6Pp5h9a8hNW?= =?us-ascii?Q?NnH2fFgw5HFO4bCP49BuK5gAFJIxo44X3cweBGP5X1Y=3D?= X-OriginatorOrg: os.amperecomputing.com X-MS-Exchange-CrossTenant-AuthSource: BYAPR01MB4293.prod.exchangelabs.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 11 Jan 2021 17:57:44.0034 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 3bc2b170-fd94-476d-b0ce-4229bdc904a7 X-MS-Exchange-CrossTenant-Network-Message-Id: f596b5d7-1974-4a63-20bd-08d8b65a65af X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: xkRDvWOk4VyNa6ksA69CvjD4Dr13R1xytJUCQF3J+YAXJibfI/IvKK0i+QiQYP/Gwlo0UA11qIXAQeNpTGuKuJCYUpdvh04RqtM3SerJ2GTx4DwnZY6rVUug8rH9RSSs X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR01MB3878 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 11, 2021 at 10:56:36AM +0000, Will Deacon wrote: >On Sat, Jan 09, 2021 at 09:36:15PM -0800, vanshikonda@os.amperecomputing.com wrote: >> From: Vanshidhar Konda >> >> Increase the default value of NR_CPUS to 512 from 256. This will >> enable the defconfig kernel to support platforms that have upto >> 512 cores. > >Do we already support such a platform, and what is it? I'm fine with bumping >the number, it's just nice to be able to say specifically _why_ we're dong >it. I'm not aware of any publicly available systems that run into the 256 core limitation. At Ampere we have internal systems that would benefit from this change as they support more than 256 cores. Thanks, Vanshi > >Thanks, > >Will