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 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=-5.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 55152C433DB for ; Mon, 11 Jan 2021 18:26:52 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 03A712250E for ; Mon, 11 Jan 2021 18:26:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 03A712250E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=5m8mCSWE4yQsB0xc8HMTVAilvRIvXS/wH6hB429wlX0=; b=rN82RzPxCk6mK60GuenJxhv+G 9AH3l6dHSXsy8cMVhZqmhPpE4T2WEYVaO3mjvQ4l/dI98LjVQAlw0ZvEbMz9kjT7Cn19nXUEAPZn2 FE5thijgaF8Rjfpnj8IU/0Yl+Dt5DrzLn1CFWY4RZbAkMFnjKG7HaVM7PZsQw+Ub3uO5PaPKLDaoE hbjr4WMTGA+cevO5lxDcFdgxZxcuHsqZwtK6pDM57q5XDGyyKh8IsKaISBkBLQsPJxq6Dhfjt8VMu B6e8dCvdZiLE4f2aoEeST211SA9XNfVVfhcgyp5rE2+8EzATBpBCLhAtdeMkSN9Ts5d8TouuuUKLe TAsHGHYpQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kz1sn-0008KS-4T; Mon, 11 Jan 2021 18:25:37 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kz1sh-0008IC-NV for linux-arm-kernel@lists.infradead.org; Mon, 11 Jan 2021 18:25:34 +0000 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 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-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210111_132531_916943_11C7FC40 X-CRM114-Status: GOOD ( 19.14 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: patches@amperecomputing.com, Will Deacon , Vanshidhar Konda , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.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 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel