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 967FFC433EF for ; Tue, 30 Nov 2021 23:37:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345255AbhK3Xkb (ORCPT ); Tue, 30 Nov 2021 18:40:31 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42226 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345628AbhK3XkY (ORCPT ); Tue, 30 Nov 2021 18:40:24 -0500 Received: from mail-qk1-x72f.google.com (mail-qk1-x72f.google.com [IPv6:2607:f8b0:4864:20::72f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3F566C061574 for ; Tue, 30 Nov 2021 15:37:04 -0800 (PST) Received: by mail-qk1-x72f.google.com with SMTP id b67so28799020qkg.6 for ; Tue, 30 Nov 2021 15:37:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=QRFrGSoUXQy5HyRnh2s9d9Qk3ennLiQfcJOlftVc0Jg=; b=smhhc1pkJ5jt13RJCClZy3YgbdRAfvgYw6fDJccZT8DLgPBFMHRWplO+Mk9pOkg9Zn SPYZYCytnH2cqy6u2Xn1JmGkwap8+LL8sjRykeRzQP3eYTevtXSP3mwugLEPkLHF0A9n sqpYVl/GScee7RhDf4NYIE+74qb01LBFn5VELU3JBrzYNOwaYwtHdH4W5W1u+GNJvz+q AYrh4Wv1fMe2AhRS6lKSY1L0dl2LuGhDdYLYV/h+LA25xwSdOLb3bUnEWu94Hd4OT4G0 eab19p2K3kH0c6B8uUH1OAgpj7u109ibf+hhEy1+TykUg/y6knwuSCvwCBMGT/jn1W72 tDsA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=QRFrGSoUXQy5HyRnh2s9d9Qk3ennLiQfcJOlftVc0Jg=; b=SdT2Vfg0Hv0A2iO73GQ45xiRXdrpAKF2HKcyx2UbUTB5HrCuqivmFkW7x9Rw+wzI0R B1HlbdwbbelFCJhL+WC8yAX3tbgyiFGil+rQPI8boCMjMsVYxD7UQ1aW4Z0WmtcrHXsG +KcGAgCJCyZUF9OAgAGLTUoJ36nC6WooP95ciP2gIkfUXUBY0Am3QrfWiClqgAg67vix FFDSJskgYjonEWtqMtZ3fxquhhpjRvtnJ3iL7Z5J0QEMmipkkhtVkviTMvSnpWzdyEAQ RTvlEN6nE5hy6ejREzEtPmGxV+FbsgP+Wsq8Yip3Q5G6tOYwWADfc9eTzArkBXIPkZ3X 91sg== X-Gm-Message-State: AOAM532M8zc9eYS+ee/rUxa60tgVAEsfOLjnWb4KTjdWa0hYuqEi8dj1 aJp8KWxJ0KAXpvahQfxzxME37+Z6+lh62j9Z5kb1Ng== X-Google-Smtp-Source: ABdhPJzGtXjdMbMM/GsyjUK1dt6LJdKXXx5TXzyfV3qsBUJLVLduzkwVY1GI2ihcB867i4GvIboh6gWmKxGwbpqAO5c= X-Received: by 2002:a05:620a:4454:: with SMTP id w20mr2776732qkp.369.1638315423230; Tue, 30 Nov 2021 15:37:03 -0800 (PST) MIME-Version: 1.0 References: <20211115170241.1.I94825a614577505bd1a8be9aeff208a49cb39b3d@changeid> In-Reply-To: From: Joel Fernandes Date: Tue, 30 Nov 2021 18:36:52 -0500 Message-ID: Subject: Re: [PATCH] sched/rt: Don't reschedule a throttled task even if it's higher priority To: Doug Anderson , Qais Yousef Cc: Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Steven Rostedt , Ben Segall , Daniel Bristot de Oliveira , Dietmar Eggemann , Mel Gorman , linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 30, 2021 at 11:30 AM Doug Anderson wrote: > I know this isn't crazy urgent and I'm happy to sit and twiddle my > thumbs a bit longer if everyone is still sleepy from tryptophan, but > I'm curious if anyone had a chance to look at this. Can anyone confirm > that my script reproduces for them on something other than my system? Maybe +Qais Yousef can also chime in. Just to add, I think Doug's issue is that under RT group scheduling, he expects *other* well behaved RT tasks to not be throttled while the tasks that are misbehaving to be *gracefully* throttled. Gracefully being- it is probably WAI that they are exceeding their runtime and so *should naturally* be bandwidth-limited similar to deadline. I am not sure if the design of RT throttling considers throttling as an anomaly or something that's expected to happen. If it is expected to happen, then I see Doug's point that the mechanism shouldn't affect other RT tasks. > Does my patch seem sane? To be honest, I don't understand that bit enough :( -Joel