From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailgw1.hygon.cn (unknown [101.204.27.37]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 1A07A3DE441 for ; Thu, 25 Jun 2026 12:12:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=101.204.27.37 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782389570; cv=none; b=RCwZGP5W4a7aju6H8wqRLYkDUYbGRLSLVZ+Cdq73Kro0oJ/u/TwmJ05bbC0BmEijQPkZX4upDiNoTDtszPj/iNRgIEq4VUeeSrPxpKPL1gau+ojOZtWUm3paQADtqbBa2bWCQD/Kro11DLhdNpjzDbsvCr2vdZFygttnX26+G1U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782389570; c=relaxed/simple; bh=jFvTtLXwJLT3NSWfqVAkkGdzhuEdChLDKi3gyFDCrhw=; h=From:To:CC:Subject:Date:Message-ID:References:In-Reply-To: Content-Type:MIME-Version; b=P1csn/Qqk2hYX6heNhwC3s8+5AbG1TkpTSJSNy7ljk7vXLzQFpYvIflKfI3n41dTo4LHof+xFZQJTItDT6XDQGu0Tli7uNEK+xUvpB77ofxSppL2AyA9KJUYlnZ3+jX6g7N80Ckk35TmJpaa4QnFgeWfEPpucLauy93aYv7sOjg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=hygon.cn; spf=pass smtp.mailfrom=hygon.cn; arc=none smtp.client-ip=101.204.27.37 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=hygon.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=hygon.cn Received: from maildlp2.hygon.cn (unknown [127.0.0.1]) by mailgw1.hygon.cn (Postfix) with ESMTP id 4gmHk44NX2z2f2t; Thu, 25 Jun 2026 20:12:28 +0800 (CST) Received: from maildlp2.hygon.cn (unknown [172.23.18.61]) by mailgw1.hygon.cn (Postfix) with ESMTP id 4gmHk33nY2z2f2t; Thu, 25 Jun 2026 20:12:27 +0800 (CST) Received: from cncheex06.Hygon.cn (unknown [172.23.18.116]) by maildlp2.hygon.cn (Postfix) with ESMTPS id ECE1430004EC; Thu, 25 Jun 2026 20:10:36 +0800 (CST) Received: from cncheex04.Hygon.cn (172.23.18.114) by cncheex06.Hygon.cn (172.23.18.116) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.36; Thu, 25 Jun 2026 20:12:27 +0800 Received: from cncheex04.Hygon.cn ([fe80::1b6f:6c58:58a4:430d]) by cncheex04.Hygon.cn ([fe80::1b6f:6c58:58a4:430d%10]) with mapi id 15.02.1544.036; Thu, 25 Jun 2026 20:12:27 +0800 From: Jianyong Wu To: Peter Zijlstra CC: "mingo@redhat.com" , "juri.lelli@redhat.com" , "vincent.guittot@linaro.org" , "dietmar.eggemann@arm.com" , "rostedt@goodmis.org" , "bsegall@google.com" , "mgorman@suse.de" , "vschneid@redhat.com" , "kprateek.nayak@amd.com" , "sshegde@linux.ibm.com" , "linux-kernel@vger.kernel.org" , "yu.c.chen@intel.com" , "tim.c.chen@linux.intel.com" , "justin.he@arm.com" , Yuan Zhong , Zhiwei Ying , Huangsj Subject: RE: [RFC PATCH 0/8] sched: Extend cache-aware scheduling into topology-aware scheduling Thread-Topic: [RFC PATCH 0/8] sched: Extend cache-aware scheduling into topology-aware scheduling Thread-Index: AQHdBE/bp76hHQU4uEOXZ4UTtpyiy7ZObl6AgAC+w1A= Date: Thu, 25 Jun 2026 12:12:27 +0000 Message-ID: References: <20260625030759.25928-1-wujianyong@hygon.cn> <20260625084227.GS42921@noisy.programming.kicks-ass.net> In-Reply-To: <20260625084227.GS42921@noisy.programming.kicks-ass.net> Accept-Language: zh-CN, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Hi Peter, > -----Original Message----- > From: Peter Zijlstra > Sent: Thursday, June 25, 2026 4:42 PM > To: Jianyong Wu > Cc: mingo@redhat.com; juri.lelli@redhat.com; vincent.guittot@linaro.org; > dietmar.eggemann@arm.com; rostedt@goodmis.org; bsegall@google.com; > mgorman@suse.de; vschneid@redhat.com; kprateek.nayak@amd.com; > sshegde@linux.ibm.com; linux-kernel@vger.kernel.org; > yu.c.chen@intel.com; tim.c.chen@linux.intel.com; justin.he@arm.com; > Yuan Zhong ; Zhiwei Ying ; > Huangsj > Subject: Re: [RFC PATCH 0/8] sched: Extend cache-aware scheduling into > topology-aware scheduling >=20 > On Thu, Jun 25, 2026 at 11:07:51AM +0800, Jianyong Wu wrote: > > The current cache-aware scheduling implementation adopts an > > LLC-centric task aggregation model. While effective for workloads > > that fit within a single LLC domain, this design is fundamentally > > limited by a fixed aggregation scope that cannot scale across > > scheduling domains. > > > > This leads to a single structural limitation: the lack of > > topology-scalable task aggregation. When workload size exceeds > > the capacity of an LLC domain, the scheduler cannot extend > > aggregation to higher-level domains, and locality cannot be > > preserved effectively. At the same time, higher-level topology > > information such as NUMA domains cannot be consistently utilized > > for placement decisions. > > > > This patch set addresses this limitation by extending > > cache-aware scheduling into topology-aware task aggregation. > > The aggregation scope becomes hierarchical and can dynamically > > expand or contract across scheduling domains based on workload > > demand. > > > > Task aggregation starts at MC or LLC domains under light load, > > and expands to NUMA and higher-level domains as load increases, > > and contracts when load decreases. >=20 > Urgh,... that only really works if the topology has a low branching > factor. >=20 > I would much rather see things move towards a mask of cache domains, > rather than any single one, where the number of bits in the mask is > minimal vs the concurrency. OK, let me try this. >=20 > This has already been mentioned a number of times, which seems to > suggest you've not actually been reading along very well :-( Sorry for missing the earlier discussion on this. Thanks Jianyong