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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B7371C49EAB for ; Sat, 26 Jun 2021 11:44:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8FDDF6191E for ; Sat, 26 Jun 2021 11:44:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229984AbhFZLpB (ORCPT ); Sat, 26 Jun 2021 07:45:01 -0400 Received: from shelob.surriel.com ([96.67.55.147]:33122 "EHLO shelob.surriel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229518AbhFZLpA (ORCPT ); Sat, 26 Jun 2021 07:45:00 -0400 Received: from imladris.surriel.com ([96.67.55.152]) by shelob.surriel.com with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1lx6hf-00014S-BY; Sat, 26 Jun 2021 07:42:27 -0400 Message-ID: Subject: Re: [PATCH] sched: cgroup SCHED_IDLE support From: Rik van Riel To: Peter Zijlstra , Tejun Heo Cc: Josh Don , Ingo Molnar , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , Paul Turner , David Rientjes , Oleg Rombakh , Viresh Kumar , Steve Sistare , linux-kernel@vger.kernel.org Date: Sat, 26 Jun 2021 07:42:27 -0400 In-Reply-To: References: <20210608231132.32012-1-joshdon@google.com> Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-Q8vGBBKE25AsRlE5mV6U" User-Agent: Evolution 3.40.1 (3.40.1-1.fc34) MIME-Version: 1.0 Sender: riel@shelob.surriel.com Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --=-Q8vGBBKE25AsRlE5mV6U Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Fri, 2021-06-25 at 10:08 +0200, Peter Zijlstra wrote: > On Wed, Jun 16, 2021 at 11:42:05AM -0400, Tejun Heo wrote: > > A high-level problem that I see with the proposal is that this > > would bake > > the current recursive implementation into the interface. The > > semantics of > > the currently exposed interface, at least the weight based part, is > > abstract > > and doesn't necessarily dictate how the scheduling is actually > > performed. > > Adding this would mean that we're now codifying the current > > behavior of > > fully nested scheduling into the interface. >=20 > It's a direct concequence of the hierarchical requirement. The > approach > is the only valid one. The other relative controllers that don't do > this, are simply broken. >=20 > Absolute controllers have it easier, they can be trivially flattened. I'm pretty sure CFS can be mostly flattened too, just not trivially :) Doing the delta_exectime to vruntime accounting in a somewhat delayed fashion, with never more than one or two timeslices worth of vruntime at a time being accounted, should make the flat CFS runqueue model work. --=20 All Rights Reversed. --=-Q8vGBBKE25AsRlE5mV6U Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- iQEzBAABCAAdFiEEKR73pCCtJ5Xj3yADznnekoTE3oMFAmDXEqMACgkQznnekoTE 3oNYbAf+P0FWX2/jiL/fCScDjNZOIEnpTWFyOoVumMs46Zly1HaiKJidykHivnyr EcfXp5v8OFfFV27/tIgW6LjA5V86XI/dv0Q1eqlo/rGnE/Xr3B5X2JxyzRg+H6ye hOk44vStRPVj71nd/5+kbb9Mdu3atmzyF2RzRX4/28GSVDF78l02bT+bUbj9sPbf Sf6QqzyT9BTR3szKRCC5cDY1BkV6u9id77mm/z+7ugZpR9xnLIoKSPHKoLBsS5vc 700Cg3FGeVRX7biCVAKx5qI/GXjM1PWEiJsYlYZz2z+OFk4vYKYvYSBdT1J/YfRw /PaH1mou1EyaoK9B6L5xSPnNDB9V9Q== =wO7c -----END PGP SIGNATURE----- --=-Q8vGBBKE25AsRlE5mV6U--