From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 2747628750C for ; Fri, 4 Jul 2025 08:46:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751618769; cv=none; b=d5Ys0FuNa9ka7yDdKhWUVXsjSQqRrfkUsa7MOfgY7vzIAcNdyhGsSefm0zwewPsBF/ieTv93uzwFa+D2PVL5/bAeJpAnudn3Pi3oTFKlRb/qbUrtrCW37srWqXslqVO/2q7+DdmQlzldWumSEE0B+VT3AQVSTEei3QrVJYZRIPs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751618769; c=relaxed/simple; bh=HU0oCF3SsO6xY8EQnlB2lkoCeGaZMBu9JmdYXoSnmms=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=sMMNIlecfXhXcApSUcIKWyacQSv6nZVZJTwb9J59UrE5r1cn6aO7PBLL9I+zZoc/XJgBnPUFPFAAcTg/n5HguLviQxw7egs4+KFu10WJYmt15tKiOGHtwmdp3iBKHcZtN3cowXF1Qn9E3N6LvM7pf2ej5/EL/RZSLxHKACZW1ZE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=oSCZKgVv; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="oSCZKgVv" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=BiiPFvk8pVVBJSxL7L3t13j61DBtLfP08JMvkqNoRsw=; b=oSCZKgVvDMkuC841Is/QwZap2m VDvyrkacWFey7YEIFLQ2AJKNjdwlGKCYlgcCiWZQTzJdY1E4M47UL/r+1VKktDy042QTiHRz5Dven NdVZUUujpVJdD/cPH574LTNCpimDerJPIaWdiqhpd5vnckr6/OLt3YXf3btNsXjAXtYjFa37XH+Ay +FKX6uJtMclo/uq4GaDoIrDWQRrxsrUiaZ3eA+yswpGHpwxDU+7c158dAkjabe3BUYlTRf/73Ed0i HBtMIneeGzjpEsidmBO5yTpQ+Puk6qtRl3PAo7mQv6UdPd+XJhmsNvS6TSifcA63aKe6+7dN1z3gX i8eXjroQ==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1uXc3I-00000007s3T-3ouw; Fri, 04 Jul 2025 08:45:49 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 0CCB8300212; Fri, 04 Jul 2025 10:45:48 +0200 (CEST) Date: Fri, 4 Jul 2025 10:45:47 +0200 From: Peter Zijlstra To: "Chen, Yu C" Cc: Shrikanth Hegde , Juri Lelli , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , Tim Chen , Vincent Guittot , Libo Chen , Abel Wu , Madadi Vineeth Reddy , Hillf Danton , Len Brown , linux-kernel@vger.kernel.org, Ingo Molnar , K Prateek Nayak , "Gautham R . Shenoy" , Tim Chen Subject: Re: [RFC patch v3 01/20] sched: Cache aware load-balancing Message-ID: <20250704084547.GF2001818@noisy.programming.kicks-ass.net> References: 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 Content-Disposition: inline In-Reply-To: On Fri, Jul 04, 2025 at 04:40:39PM +0800, Chen, Yu C wrote: > > > @@ -953,6 +953,10 @@ config NUMA_BALANCING > > > ?????????????? This system will be inactive on UMA systems. > > > +config SCHED_CACHE > > > +?????? bool "Cache aware scheduler" > > > +?????? default y > > > + > > > > Should it depend on EXPERT? > > IMO this could add quite a bit of overhead and maybe n by default? > > > > I would leave this to Peter and Tim to decide. Runtime controls are always better than compile time. Distros will have no choice but to enable the config option. But that is not the kind of thing you start a series with. First versions didn't even have the config option. First you make it work, then later you worry about silly detail.