From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 790781AB6F1 for ; Mon, 5 Jan 2026 16:33:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767630815; cv=none; b=MkuqsQ6D/796FWenOEZtx1oXDuJZGzMqSKX4wKqgEtjOFnuWGQGf/p5TGahfbkkG2y/oUjVtj+gYz0qOMxtzryVQxJDA17hLd/qw/73trUKDVwzB2P+B7MKJr0sScGUAVV3WuUxd1qHRH+jR0jbawpTszdKYmwMhDriwsr7Mtuc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767630815; c=relaxed/simple; bh=3/JkOyTvJPBesUBgMSr06HrFv6OIC5H4pwhAEukkYNc=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=KppvskCVFcFIlKDzaybP/xJQof9gJScJlj9lWX5j90lVWndZ7d0IoRWWfQDt1CJVpuP0xWLPiAzivLzrAXpZ5qVotYfbKq5dd4u69sYI1Mw7gvT8nokH1gKAabvBI/HRvDx/ZP+hSATII1AoTm01iut5F4PFaHzgdRDNTsNCJyA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id DABEE339; Mon, 5 Jan 2026 08:33:25 -0800 (PST) Received: from [10.1.38.150] (XHFQ2J9959.cambridge.arm.com [10.1.38.150]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D96803F6A8; Mon, 5 Jan 2026 08:33:31 -0800 (PST) Message-ID: <7341009d-b3e7-40bc-83b3-401e6e164ef5@arm.com> Date: Mon, 5 Jan 2026 16:33:30 +0000 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [REGRESSION] sched/fair: Reimplement NEXT_BUDDY to align with EEVDF goals Content-Language: en-GB To: Shrikanth Hegde Cc: x86@kernel.org, linux-kernel@vger.kernel.org, Aishwarya TCV , Dietmar Eggemann , Mel Gorman , "Peter Zijlstra (Intel)" References: <20251112122521.1331238-3-mgorman@techsingularity.net> <176339661525.498.7070393041762616565.tip-bot2@tip-bot2> <4b96909a-f1ac-49eb-b814-97b8adda6229@arm.com> <756efd17-682f-4ffc-b8d9-dbb2517bc152@arm.com> <58a80940-a104-4932-a2f2-f0c6a1a205af@linux.ibm.com> From: Ryan Roberts In-Reply-To: <58a80940-a104-4932-a2f2-f0c6a1a205af@linux.ibm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 05/01/2026 14:38, Shrikanth Hegde wrote: > > Hi Ryan, > >>> node distances: >>> node   0   1 >>>    0:  10  20 >>>    1:  20  10 >>> >>> Whereas I assume the Graviton3 has 64 CPUs (cores) flat in a single MC >>> domain? I guess topology has influence in benchmark numbers here as well. >> >> I can't easily enable scheduler debugging right now (which I think is needed to >> get this info directly?). But that's what I'd expect, yes. lscpu confirms there >> is a single NUMA node and topology for cpu0 gives this if it helps: > > If you dump /proc/schedstat it should give you topology info as well. > > (you will need to parse it depending on which CPU you are looking this from) Ahh yes, thanks! Every cpu is reported as being in "domain0 MC ffffffff,ffffffff". So I guess that means there is a single MC domain as Dietmar suggests. Thanks, Ryan