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 9643E1A2630 for ; Mon, 17 Mar 2025 17:06:13 +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=1742231175; cv=none; b=JbxXAH5PrFtSuSuTnfTWA0cwl+CAhasThDyic/svGsQoGtQRaxfuaEo9sQW+6m4X1/GAgfYW6vIWW4jnoFlxR5dbuV0zQigOo+UC5qNCtSq142VHRescKpZPhU6LsNmeO40cSXLBuyA3JZHSkEMV0dfHBriyCW9AeaoZ4bECyCA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742231175; c=relaxed/simple; bh=EKcGOxVMzjKzzpY2bAD/qKhkOsw3/ZS5jWoFiHGL9QY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=NqTvhJry/YSAGb0vtSfuhKPln8Ny/OKGntUSR+j5Yv97jmsG0tsKynF+8v1zPvU+Ypo+fJ/tv5QmFWcsJOLGgmRPoJL0YAN6XIWfQSop6WbrHcnjHxKXgMJer/mgz0QDqWHJKUJTvu2F0vMWSg1hOmSfjE0BgyTGCYod6Xc/jN4= 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=DbVpv00x; 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="DbVpv00x" 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=dGzCutVqaGoQAQTN8SMp16X3bMGayRAE4xjT/iqKqv4=; b=DbVpv00x+lyC9GE1HhMwx82/pC vST0lop5ZdDtgbprWQDxdG3UJkVQ0FDsUayc6xmlw6peWOxTTJPkEXTeyVnjOcWdYdzUiVRTLh6qc 95R8FpRI2h9eobEmTk0VvVIFVlQ7nuYJXmHUADS8KT20JsiCgIGmQOc/LgKp/LDQJYeeabEx2KBDn iksISKi5Dav5WoR8BwFG1E7VZrqThVzNCVOR0msWOMHzu8A2rjkOfq4nH/weONbOIpu6hjMJfO9iC VUYxRRoG0wIOCg+BsGyNTvpoFALPCAjP/VQruEDR5qFtIMLFv3dBJIwmD/U3p/LbL7l+BcbPeqviX uDxU772w==; 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 (Red Hat Linux)) id 1tuDud-00000003UtN-2WOY; Mon, 17 Mar 2025 17:06:03 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 2F1A6300B40; Mon, 17 Mar 2025 18:06:03 +0100 (CET) Date: Mon, 17 Mar 2025 18:06:02 +0100 From: Peter Zijlstra To: Tejun Heo Cc: Joel Fernandes , linux-kernel@vger.kernel.org, Andrea Righi , Ingo Molnar , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , David Vernet , Changwoo Min , Luigi De Matteis , paulmck@kernel.org, boqun.feng@gmail.com Subject: Re: [PATCH RFC 3/8] sched/ext: Add a DL server for sched_ext tasks Message-ID: <20250317170602.GE6888@noisy.programming.kicks-ass.net> References: <20250315022158.2354454-1-joelagnelf@nvidia.com> <20250315022158.2354454-4-joelagnelf@nvidia.com> <20250315072225.GG36322@noisy.programming.kicks-ass.net> <3b244939-6d55-4d86-8b77-a9a7629f8239@nvidia.com> <20250317103101.GC34541@noisy.programming.kicks-ass.net> 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 Mon, Mar 17, 2025 at 06:57:19AM -1000, Tejun Heo wrote: > Hello, > > On Mon, Mar 17, 2025 at 11:31:01AM +0100, Peter Zijlstra wrote: > > On Sat, Mar 15, 2025 at 07:15:27PM -0400, Joel Fernandes wrote: > > > If so, that will not handle the case where the system has both > > > FAIR and EXT tasks in the mix (EXT has a partial mode where certain tasks can be > > > made EXT with certain others left as FAIR) and FAIR runs 100% and starves EXT. > > > > Well, you did not mention that issue, you only babbled about RT. > > > > I did point out that issue with ext, and TJ said this mixed mode wasn't > > really meant to be used or somesuch. > > It's true that most of the current use cases don't use mixed mode. That > said, some folks are interested in it and if we can prevent starvation from > fair saturating CPUs in mixed mode with a DL server, that'd be really nice. > Would it be possible to toggle the reservations depending on the ext's > operation mode? Yeah, that should be doable.