From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from gentwo.org (gentwo.org [62.72.0.81]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 238E12F0C73 for ; Wed, 13 Aug 2025 23:07:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=62.72.0.81 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755126437; cv=none; b=IPcm1Js11cXDG2cxeUbw0x8ph7tgriVHJzuvgXcObi7Gsi1OHSPnrZ5ptokYzU4wUr2FBvZbfVTGYN2o7Ea6k1BYdxz01l5Lrnjue2S5Hzact7MhkN7lqTiT2cODuPDJR2WSB/Tc7tuDDVNowqW4tR6CnKG4mbapqxWotp0H0C0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755126437; c=relaxed/simple; bh=yVULnksl4OKg12CxxFYhPKFfdwxXkGZSNGl9YwQ9v2c=; h=Date:From:To:cc:Subject:In-Reply-To:Message-ID:References: MIME-Version:Content-Type; b=DGCddrt+myIqwSa9FG+IWLCXOWWom1+hfHGD+BXqRqqHdLooR6fJjlfoKos2aqhW9eJt+cl/n12Zg1mjKoaKplgsXW7Q3BdA2zaGUog+00zzOQeuAjj/IRmvDaBTi33OGVfVsi4pA+qJr6yoU2c0BCEclgYGvAS3l9aTMxhJpzQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=gentwo.org; spf=pass smtp.mailfrom=gentwo.org; dkim=pass (1024-bit key) header.d=gentwo.org header.i=@gentwo.org header.b=c9cXknZD; arc=none smtp.client-ip=62.72.0.81 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=gentwo.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gentwo.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=gentwo.org header.i=@gentwo.org header.b="c9cXknZD" 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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII 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.