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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 421B6C87FCF for ; Wed, 13 Aug 2025 23:10:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type:MIME-Version: References:Message-ID:In-Reply-To:Subject:cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=L2TmOU/FysjsHnOJuDF0/FyfY9rYX5x9MA3yl9yoYVc=; b=uAYGRDXUic/rx+ovoWDObhWEV+ dxB6HjouNv3jACBw3goWZvCTPECkpl7ckfsiarndjvOD7w7reco8fEKDhmXEMetqykJxePlLBADrL hwfU+Vo/mYS58G9QcQBrXUtQZtUvO6b/FmfJnO7iSk4HNepNexF8nGaCNcr4yuqYiixAhbNG+ohcw gZlGeAUnv4jpQwmc3SffRwi9g+LSZPI+NwNl8se1R2qTPiMYJv+UMnydbCMP9z5sH6NRB3CSlC0Tk WQ3uVDSVArv+IFoOjuqt6XrxCvBQ2MZGsLtGAzSHr5ZGzZDXrxbyJEvs3ZwWOa3ClfmshAes2TfRH cknI4XoA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1umKbS-0000000FER6-1gdM; Wed, 13 Aug 2025 23:09:54 +0000 Received: from gentwo.org ([62.72.0.81]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1umKYt-0000000FE8H-3ZPm for linux-arm-kernel@lists.infradead.org; Wed, 13 Aug 2025 23:07:16 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gentwo.org; s=default; t=1755125807; bh=yVULnksl4OKg12CxxFYhPKFfdwxXkGZSNGl9YwQ9v2c=; h=Date:From:To:cc:Subject:In-Reply-To:References:From; b=c9cXknZDA7jyMse2KwiTCmhQnLux9UKA/5fhjfEmP5A5B2TlCljggrqBrGgxMyVbs uvPkj/FSbvMznPSZdPr95SfEj6EpM9re3w44gRah73+XyU05DKRl+AmPV2FjXmKZoB FCBoKE4TInJVdKQyFAb3GKWl0c9/xEjxlIc5Sh+8= Received: by gentwo.org (Postfix, from userid 1003) id C26E3401FB; Wed, 13 Aug 2025 15:56:47 -0700 (PDT) Received: from localhost (localhost [127.0.0.1]) by gentwo.org (Postfix) with ESMTP id C15174010E; Wed, 13 Aug 2025 15:56:47 -0700 (PDT) Date: Wed, 13 Aug 2025 15:56:47 -0700 (PDT) From: "Christoph Lameter (Ampere)" To: Sudeep Holla cc: Jeremy Linton , Huang Shijie , catalin.marinas@arm.com, will@kernel.org, patches@amperecomputing.com, Shubhang@os.amperecomputing.com, krzysztof.kozlowski@linaro.org, bjorn.andersson@oss.qualcomm.com, geert+renesas@glider.be, arnd@arndb.de, nm@ti.com, ebiggers@kernel.org, nfraprado@collabora.com, prabhakar.mahadev-lad.rj@bp.renesas.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] arm64: defconfig: enable CONFIG_SCHED_CLUSTER In-Reply-To: Message-ID: References: <20250808025533.6422-1-shijie@os.amperecomputing.com> <2d9259e4-1b58-435d-bf02-9c4badd52fd9@arm.com> <20250813-gifted-nimble-wildcat-6cdf65@sudeepholla> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250813_160715_926298_A77D8038 X-CRM114-Status: GOOD ( 13.84 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, 13 Aug 2025, Christoph Lameter (Ampere) wrote: > Can we figure out which platforms benchmarks were affected and why? > > It seems the notion of a "cluster" on ARM64 is derived (I guess a better > word than "invented" hehe) from sibling information instead of PPTT. But > using that information should work fine right? Sorry no that is not correct. The cluster information is correctly read from the ACPI tables and the cluster ids are avaialble in /sys/devices/system/cpu/cpuXX/topology/cluster_id if CONFIG_SCHED_CLUSTER is enabled. If there is an issue then it is a problem with the vendor firmware providing cluster id configurations via ACPI that cause regressions. We could add a blacklist for those platforms to avoid regressions but we should not allow that to hinder us to enable full support for clustering on ARM64.