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 0F9321DE2A8 for ; Fri, 6 Dec 2024 20:30:08 +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=1733517011; cv=none; b=O+/Nek+9EKc/dHfr3ypQuKSfLxaQA5kXb4xwQ5zQsFxovAzTCDFtXbQrJ7BrIRQPW6QpHxKeiltzljfA4+cjRjOs3ilJsQZo378oMmFvO8GE7psZCtynGTgbcinVAblnCKCYaIzEKN4l/6kqShVRV17UkGRhBb7RMV2RjM7xU5o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733517011; c=relaxed/simple; bh=rU1gOVpYMhHIJEcOgVuKGTFJrl7p9VeyIcOtctgJagw=; h=Message-ID:Date:MIME-Version:Subject:To:References:From: In-Reply-To:Content-Type; b=HARVG3MK2QkXY8cMxRjKNdeMNqrbJhdUX13d5MwsBNkxtq4YEz5Scnh4wgMJ4QVA4T8y5oQyXRKYv1aVCEqfZfUQDytzEO5ZPwgoTSjSQFqYTf6UHPo/pu4T85pFsGkHASLOsxkhU95rrQVaaeI4zNnMmGftii5MaSXKdiPfCVw= 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 28DFF12FC; Fri, 6 Dec 2024 12:30:36 -0800 (PST) Received: from [192.168.0.16] (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id A58CB3F58B; Fri, 6 Dec 2024 12:30:07 -0800 (PST) Message-ID: <2ae90276-67f8-4b46-9cc5-1f7062eadfff@arm.com> Date: Fri, 6 Dec 2024 20:30:05 +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: [SCHED] any modern replacement for RT_RUNTIME_GREED in the mainline kernel? To: Chris Friesen , LKML References: <49a1c1eb-5e80-4eb2-b882-a2df3ec12012@usask.ca> Content-Language: en-US From: Christian Loehle In-Reply-To: <49a1c1eb-5e80-4eb2-b882-a2df3ec12012@usask.ca> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 12/6/24 18:12, Chris Friesen wrote: > Hi all, > > Some time back (https://lore.kernel.org/lkml/fa5b1b55d8934c6a0e02e04a7ad6afdf4012c2e0.1478506194.git.bristot@redhat.com/) a patch was proposed that would allow high-CPU usage RT tasks to use 100% of the CPU as long as there were no non-RT tasks that wanted to run, but if a non-RT task did want to run the RT-throttling would kick in to prevent starvation and deadlocks. > > It was rejected for philosophical reasons, with a mention of a hypothetical deadline server being the "proper" solution. > > Has anything been done in this area in the years since then? There has! The 'hypothetical deadline server' was implemented and is part of 6.12 https://lore.kernel.org/lkml/cover.1716811043.git.bristot@kernel.org/