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 0DDF0EB64D8 for ; Wed, 14 Jun 2023 14:16:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245516AbjFNOQV (ORCPT ); Wed, 14 Jun 2023 10:16:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42900 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245532AbjFNOQG (ORCPT ); Wed, 14 Jun 2023 10:16:06 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5FA5110CB for ; Wed, 14 Jun 2023 07:15:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1686752118; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=gs9UsFHiOqFVLHIkbMkZs+XlwUJlhoeynhzk+GnTL8Q=; b=fBhNcUQ51rw06ne3TQ2VLDajj/mjFzlfFNJRPJUmDaISzu9cQlGvIbqN45bYLY8sZhdY/Q 3sH1wI8uS0Mf7bOpHQ7w9JoAbqmeq3R30IAgtwLTvFvQeoCe/Fx6c1UxtKYOkhfefeqmus /tIoaDUfcKOXmx1OxoTHgCRIqyMzcRg= Received: from mail-wr1-f69.google.com (mail-wr1-f69.google.com [209.85.221.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-278-Wav4OnFRP12MaEttHWo0eg-1; Wed, 14 Jun 2023 10:15:17 -0400 X-MC-Unique: Wav4OnFRP12MaEttHWo0eg-1 Received: by mail-wr1-f69.google.com with SMTP id ffacd0b85a97d-30fb1f3c30aso1813802f8f.0 for ; Wed, 14 Jun 2023 07:15:16 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1686752115; x=1689344115; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=gs9UsFHiOqFVLHIkbMkZs+XlwUJlhoeynhzk+GnTL8Q=; b=DVVb0RE7MpibuoNgTKsZbXa0y0UIFlNJgOSDXRIYFZJsPaMowdoNOoHosVXUTxDKpe qbcy5pD2LcHM//+5/4hwLqGMDqr0nlLW+5IrEUiQuJJJFA3pIj2pfFp6fYN8H6du776N SKaZh/n8/G9ziyseYvhNa0PZksTWpuOvlM1s+jgCuLU3+ZQLvWDA6dGTogIGutze35Yy r3zjXQF7oXmdZCTQJd1QggJQCkFTCZum53JzKlESTVlyM6zqbaE7WA8I2Q+RUJP9LOxa mP4oIuGA9CsLGNFCH+DraqbkRjPutR1fPb6u/YTorjSUVrChHoq7G0ky2zmweGCnW1aa m+bg== X-Gm-Message-State: AC+VfDx46yNUGvFLBQ0ocQiyCMyE64P86xatfwCcwyUxSUlytZLfDivU fpUOnClbWPxeoi/T6f4sdeWRsu2ixZX07m2TuC1DNkN31/ZLbbMPDlfmN653zfy5jWsioqj/A7X 3Sgf7YnvjjPi03NeNBvMC0sE5 X-Received: by 2002:a05:6000:100a:b0:30a:a478:f559 with SMTP id a10-20020a056000100a00b0030aa478f559mr9364248wrx.2.1686752115778; Wed, 14 Jun 2023 07:15:15 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ6Ughal3Ksk9mWSBNbC9/117BFdtAMq/ce7h59A0MFXhuh3csYI3NW44NB41eA0ulZ91dSNCw== X-Received: by 2002:a05:6000:100a:b0:30a:a478:f559 with SMTP id a10-20020a056000100a00b0030aa478f559mr9364231wrx.2.1686752115421; Wed, 14 Jun 2023 07:15:15 -0700 (PDT) Received: from localhost.localdomain ([151.29.46.22]) by smtp.gmail.com with ESMTPSA id m7-20020a7bca47000000b003f80b96097esm15014202wml.31.2023.06.14.07.15.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 14 Jun 2023 07:15:14 -0700 (PDT) Date: Wed, 14 Jun 2023 16:15:12 +0200 From: Juri Lelli To: Daniel Bristot de Oliveira Cc: Joel Fernandes , Ingo Molnar , Peter Zijlstra , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , linux-kernel@vger.kernel.org, Luca Abeni , Tommaso Cucinotta , Thomas Gleixner , Vineeth Pillai , Shuah Khan Subject: Re: [RFC PATCH V3 6/6] sched/fair: Implement starvation monitor Message-ID: References: <841849b5-1f9c-4f0e-2de8-1da278256888@kernel.org> <4849295d-9aef-836f-0e5f-063e2075380a@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4849295d-9aef-836f-0e5f-063e2075380a@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hey, So Daniel provided the gory details :) .. but please let me highlight one of his points below, which I think it might clarify why we might want to start with a special case, patch 6 improved approach, before possibly moving to more complex implementations. On 14/06/23 15:45, Daniel Bristot de Oliveira wrote: ... > By postponing the enqueue/replanishment of the DL server here, we are fixing the > problem in a practical way, that works without breaking existing useful properties & > use-cases. In my understanding, if we simply postpone actual activation of the DL server up to the point it really needs to boost/run for giving CFS tasks some breath (the infamous 0-laxity :), we save RT tasks from useless interruptions and still can keep EDF/CBS working w/o much changes. It looks like a low hanging fruit, small improvement on what we have today than doesn't prevent us for implementing more complex features (i.e., full blown hierarchical scheduling, alternative schedulers) in the future if the need arises. Thanks! Juri