From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 49813EC8748 for ; Thu, 7 Sep 2023 15:35:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344237AbjIGPco (ORCPT ); Thu, 7 Sep 2023 11:32:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40258 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241882AbjIGPaz (ORCPT ); Thu, 7 Sep 2023 11:30:55 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5A4D51FC6; Thu, 7 Sep 2023 08:30:30 -0700 (PDT) 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=CmfnIP/qJkmApsvJ1mr5W1MC2O3k/lCNMHjccWhVsKw=; b=fRdYGkGqNR4pUJvPkojbJwWsMz sZdrBUP2CCBXfu6cwHGF0sztUW3cyBK333/tARup1Ebp0/U8GpoIuMyekEWomOMjekm1eRODZ0PsN 27E4y1oQO+S+Y7TwUxHXpQdUCj2yT7rXLjg8ingocYVlPxnBk5BijEgzdNZnCDc7ybMs0HyCH59Bk jOuhAOSPbsVVW2Wa7NFNeCsH5ysmaDxtqjhR6peKzFKCAMID/kRLCU0T6BCHxy+0ti4G4xgW4BkKj I/m6geBKSAhNYIRMaaMoVtth8g9hhhugQ1e8Fz5ns4mzRMX275EpSrbniexf+SJEJgrN01WjtIYor k42vqmdQ==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1qeF4D-001opO-18; Thu, 07 Sep 2023 13:29:07 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 730C8300687; Thu, 7 Sep 2023 15:29:06 +0200 (CEST) Date: Thu, 7 Sep 2023 15:29:06 +0200 From: Peter Zijlstra To: Lukasz Luba Cc: Qais Yousef , linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, "Rafael J. Wysocki" , Ingo Molnar , Dietmar Eggemann , Vincent Guittot , Viresh Kumar Subject: Re: [RFC PATCH 0/7] sched: cpufreq: Remove magic margins Message-ID: <20230907132906.GG10955@noisy.programming.kicks-ass.net> References: <20230827233203.1315953-1-qyousef@layalina.io> <20230906211850.zyvk6qtt6fvpxaf3@airbuntu> <6011d8bb-9a3b-1435-30b0-d75b39bf5efa@arm.com> <20230907115307.GD10955@noisy.programming.kicks-ass.net> <89067f71-9b83-e647-053e-07f7d55b6529@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <89067f71-9b83-e647-053e-07f7d55b6529@arm.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 07, 2023 at 02:06:15PM +0100, Lukasz Luba wrote: > > Many extentions to the periodic task model are possible, including > > things like average runtime with bursts etc.. all have their trade-offs. > > Was that maybe proposed somewhere on LKML (the other models)? RT literatur mostly methinks. Replacing WCET with a statistical model of sorts is not uncommon, the argument goes that not everybody will have their worst case at the same time and lows and highs can commonly cancel out and this way we can cram a little more on the system. Typically this is proposed in the context of soft-realtime systems.