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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 3DA7FC433E0 for ; Mon, 11 Jan 2021 18:26:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 08B0A2250E for ; Mon, 11 Jan 2021 18:26:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390426AbhAKS0L (ORCPT ); Mon, 11 Jan 2021 13:26:11 -0500 Received: from mail.kernel.org ([198.145.29.99]:39670 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727225AbhAKS0L (ORCPT ); Mon, 11 Jan 2021 13:26:11 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8136E2250E; Mon, 11 Jan 2021 18:25:29 +0000 (UTC) Date: Mon, 11 Jan 2021 18:25:27 +0000 From: Catalin Marinas To: Randy Dunlap Cc: Vanshidhar Konda , Will Deacon , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, patches@amperecomputing.com Subject: Re: [PATCH] arm64: Kconfig: Increase NR_CPUS default to 512 Message-ID: <20210111182526.GB17941@gaia> References: <20210110053615.3594358-1-vanshikonda@os.amperecomputing.com> <20210111105636.GA7071@willie-the-truck> <20210111175741.ldifmv7uhdekbq5d@con01sys-r111.scc-lab.amperecomputing.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 11, 2021 at 10:03:18AM -0800, Randy Dunlap wrote: > On 1/11/21 9:57 AM, Vanshidhar Konda wrote: > > 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. > > But what does that have to do with the default value? > Do you expect to run defconfig kernels? > I don't ever expect that. We still aim for the arm64 defconfig to run on all supported SoCs, even if not optimally. Distros indeed tweak the config to their needs. -- Catalin