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=-0.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 93216C433DF for ; Tue, 16 Jun 2020 17:07:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7079C2098B for ; Tue, 16 Jun 2020 17:07:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="hH5W1bOg" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730915AbgFPRHw (ORCPT ); Tue, 16 Jun 2020 13:07:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59006 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729005AbgFPRHv (ORCPT ); Tue, 16 Jun 2020 13:07:51 -0400 Received: from merlin.infradead.org (unknown [IPv6:2001:8b0:10b:1231::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8BA20C061573 for ; Tue, 16 Jun 2020 10:07:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; 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=bX5RxJCfhao4qGkqFy8rLm+I3C4jvjPT2fFLvPCoBgM=; b=hH5W1bOgR9508FnCl3pPwtAr26 z3wWRiIK2CQJX3/v5uyHd3+uX9UZU6RGKVo3ZnaSh2rJCMI1qjWzT29NIrAfXSnVycoe7YGuXo6DX 9go0YDbtqRsJ1Ox0CWVmMegK8YvuAJSXzP2RZHwWZ3Gg1XWKMEMaDi8176Zr3xu0Wqcps5ZRcXRO+ Ux87ere+iHJWwzlSYoMV5OVzXL5wA1qH+8v+AFRJINTITDJWbeCD/Q0S5kmOm3Aaiqb418JsJelTz mcQ8+LmEU7JQBkBYCQIPs0gucPShKKNE/50cDRvSmpSunWCadd/3b4FX1Fqk320Y8bLFqQ+/ro3Dz rr9P0CeQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jlF3L-0001lX-Tc; Tue, 16 Jun 2020 17:07:16 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 8D3D53017B7; Tue, 16 Jun 2020 19:07:11 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 6B7522038E4F2; Tue, 16 Jun 2020 19:07:11 +0200 (CEST) Date: Tue, 16 Jun 2020 19:07:11 +0200 From: Peter Zijlstra To: Steven Rostedt Cc: Lichao Liu , mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, bsegall@google.com, mgorman@suse.de, linux-kernel@vger.kernel.org Subject: Re: [PATCH] sched/rt: Don't active rt throtting when no running cfs task Message-ID: <20200616170711.GZ2531@hirez.programming.kicks-ass.net> References: <20200616123729.153430-1-liulichao@loongson.cn> <20200616095027.1a2048d0@oasis.local.home> <20200616140158.GY2531@hirez.programming.kicks-ass.net> <20200616105900.5cb0671d@oasis.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200616105900.5cb0671d@oasis.local.home> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 16, 2020 at 10:59:00AM -0400, Steven Rostedt wrote: > On Tue, 16 Jun 2020 16:01:58 +0200 > Peter Zijlstra wrote: > > > On Tue, Jun 16, 2020 at 09:50:27AM -0400, Steven Rostedt wrote: > > > On Tue, 16 Jun 2020 20:37:29 +0800 > > > Lichao Liu wrote: > > > > > > > Active rt throtting will dequeue rt_rq from rq at least 50ms, > > > > When there is no running cfs task, do we still active it? > > > > > > > > > > This is something I would like to have. > > > > > > Peter, what's your thought on this? > > > > I'd love to just delete all of this.. that said, I'm not sure this > > change makes sense, because it doesn't deal sanely with the case where > > the task will appear right after we did this. > > I haven't looked closely at the surrounding code, but wouldn't it get > throttled in the next period? Do we care if a task has to wait a bit > longer? Either way around, who cares? > > The right thing to do is that fair deadline server thing. > > But we've been saying that for years now. Hey, I even coded most of it, but clearly nobody cares about this enough to finish it ...