From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.15]) (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 7306E32AACE for ; Wed, 25 Feb 2026 22:56:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.15 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772060161; cv=none; b=r9yLhrHrGreNJWjhJ5D6X1xsFzMeDi4uyOYIUUOA8qyMdhmR1LSBqOG+JSbBnYOpC5BMHFECdrht0Ynq+5dl6HAamTDcrfk1u0eX28vwlb/i0hn4xbtjrGMktaw08GoFzwPrKFbANs7h/H9L0zRQahEcYsN1Fc9yYXgO//ZToV4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772060161; c=relaxed/simple; bh=MFSsC/h2zuNCq1uEQT+fqs84byJI9+3UOAPMq8wFqwQ=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=uedJEV/m7PUIwIAw6i6txbepIzzV+1RZ7wSzgpnn+fnUJLxj8FefdCTB4Y9dmFfw/goXFhDoIQhTK/1XAnHZ1vLoHA5dgpuv+2NZjz8rlQ9SnFs7etl3s0MfLf/5pc6zvhQKikfsveonMmiTgMsFzNo5BG/SmG56O0rxGFZvOGQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=Yh61+Pwh; arc=none smtp.client-ip=198.175.65.15 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="Yh61+Pwh" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1772060161; x=1803596161; h=message-id:subject:from:to:cc:date:in-reply-to: references:content-transfer-encoding:mime-version; bh=MFSsC/h2zuNCq1uEQT+fqs84byJI9+3UOAPMq8wFqwQ=; b=Yh61+PwhyuOcAbUcEL1MOb5KfwoNkATFAqbveOwTpBxwyzLX8LG0zzV1 JUiqHpmgHDtjYOHWcTRatly5URUY3AgrxqwgwCm8ujNIpQrVz7fSiKrG9 ZgfwhugDR6P0WQiFjX/CxegCSL34Ra3qVcu3TQEnHN9dqzv0ZV5J0bmiP iH2DSRSirPK2wr0GIDn83M25n8JlYbTRT0Z/8TExZfvwQXu4ESVbhlrJH HdMALEF8PjlqXImOCO/pi3MYYMndDv4LM+os9hlBvQW/0VY3VtbnOiYvH z2OWzvN8oFIDs2NcsX3TMURCljlAi7/wEkQOKGD9lYHPxG2xmKsyur108 g==; X-CSE-ConnectionGUID: Yo3fgehqT5mcAheayJiS1Q== X-CSE-MsgGUID: stGqw2O8TwisdgnP3G1f/w== X-IronPort-AV: E=McAfee;i="6800,10657,11712"; a="76718462" X-IronPort-AV: E=Sophos;i="6.21,311,1763452800"; d="scan'208";a="76718462" Received: from orviesa002.jf.intel.com ([10.64.159.142]) by orvoesa107.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Feb 2026 14:56:00 -0800 X-CSE-ConnectionGUID: U9SwUeOgSwmZZnFSGFcGYw== X-CSE-MsgGUID: McikHmczQZKb8Aga/Xoolw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.21,311,1763452800"; d="scan'208";a="246923213" Received: from schen9-mobl4.amr.corp.intel.com (HELO [10.125.111.101]) ([10.125.111.101]) by orviesa002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Feb 2026 14:55:59 -0800 Message-ID: Subject: Re: [PATCH v2] sched/topology: Check average distances to remote packages From: Tim Chen To: Peter Zijlstra Cc: "Chen, Yu C" , Kyle Meyer , bp@alien8.de, dave.hansen@linux.intel.com, mingo@redhat.com, tglx@kernel.org, vinicius.gomes@intel.com, brgerst@gmail.com, hpa@zytor.com, kprateek.nayak@amd.com, linux-kernel@vger.kernel.org, patryk.wlazlyn@linux.intel.com, rafael.j.wysocki@intel.com, russ.anderson@hpe.com, x86@kernel.org, zhao1.liu@intel.com Date: Wed, 25 Feb 2026 14:55:58 -0800 In-Reply-To: <20260225223024.GA606826@noisy.programming.kicks-ass.net> References: <20260223170314.GU1395266@noisy.programming.kicks-ass.net> <20260225123052.GN3016024@noisy.programming.kicks-ass.net> <20260225154409.GD1282955@noisy.programming.kicks-ass.net> <20260225163246.GX1395416@noisy.programming.kicks-ass.net> <62f610811c1b1cba7e282b6e855baba11f7f49a6.camel@linux.intel.com> <20260225223024.GA606826@noisy.programming.kicks-ass.net> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.58.1 (3.58.1-1.fc43) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Wed, 2026-02-25 at 23:30 +0100, Peter Zijlstra wrote: > On Wed, Feb 25, 2026 at 01:37:11PM -0800, Tim Chen wrote: > > On Wed, 2026-02-25 at 17:32 +0100, Peter Zijlstra wrote: > > > On Wed, Feb 25, 2026 at 04:44:09PM +0100, Peter Zijlstra wrote: > > >=20 > > > > Yes, so this assumes that all u sized clusters on the trace are sim= ilar > > > > and 'sane' without verification. > > >=20 > > > That gave me an idea; how's this then? > >=20 > > Sorry I was sick for a few days. Just catching up on this > > thread here. I think your patch takes care of both GNR SNC-3=C2=A0 > > with 3 compute dies (with non-symmetric remote > > distances) and generic SNC-2 with 2 dies (symmetric > > distances) very well. > >=20 > > Minor suggestion below for the patch. > >=20 > > Will ask the original GNR teams with the problem to try > > it out. >=20 > Since HPE can obviously have a sane SLIT table; why can't we simply > claim the SLIT table they had is broken and needs fixing? >From what I can see HPE seems to use SNC-2 variant of GNR so the SLIT is symmetric. Unfortunately in the topology for the 2 socket GNR that has 3 dies, there are truly unsymmetric paths from between die A to die B between remote sockets from what I'm told.=20 >=20 > Also, is there really no enumeration of the SNC mode available; must we > really divinate? Let me dig into that a bit. I was also thinking with that information, it will make the code a lot simpler. Tim