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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 D4A82C54FCB for ; Wed, 22 Apr 2020 15:39:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9F9612076E for ; Wed, 22 Apr 2020 15:39:44 +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="WDwPpELf" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726640AbgDVPjn (ORCPT ); Wed, 22 Apr 2020 11:39:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56640 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725980AbgDVPjn (ORCPT ); Wed, 22 Apr 2020 11:39:43 -0400 Received: from merlin.infradead.org (unknown [IPv6:2001:8b0:10b:1231::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 07822C03C1A9 for ; Wed, 22 Apr 2020 08:39:43 -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=FoLUof5mdWUo8b+92mC8LHdFdzDhi/CgXbqz2mqJj/U=; b=WDwPpELfKA5q/XesRT5H2w8UCz 9qhy6l4xRkAZKXTtdIk2VwFSjMuswZzkPG+1D0SeqZP3asQhp7pzTQ34Ey0KvpSS54R9Tdi94KGNH 4cYIFaHg1jGiE9zDb6sfEEIWfMioJSDycnVIqWPO5cXaTdlYa5/Bm32gUY6ZWbctw/rzae2jD209T tQBmTfchAB38KQj4ZP2p6/kEzzfiOhnPF9WW/T0WtQdnes13dV0monZ75wXdLEq7Q9WvJa74zrCV1 oq/8Lchkt0JDkxahGe349mNoeLb6BWnD5tFtBDBcU39mxrBB7LjMsi4esmYTwQb4aoAifKkKFY35M GRTkDYWQ==; 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 1jRHSy-0003dx-Fg; Wed, 22 Apr 2020 15:39:12 +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 67BEF300739; Wed, 22 Apr 2020 17:39:10 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 30D32286B71BE; Wed, 22 Apr 2020 17:39:10 +0200 (CEST) Date: Wed, 22 Apr 2020 17:39:10 +0200 From: Peter Zijlstra To: Vincent Guittot Cc: Ingo Molnar , linux-kernel , Thomas Gleixner , Steven Rostedt , Qais Yousef , Juri Lelli , Dietmar Eggemann , Ben Segall , Mel Gorman , John Stultz Subject: Re: [PATCH 13/23] sched,ion: Convert to sched_set_normal() Message-ID: <20200422153910.GN20730@hirez.programming.kicks-ass.net> References: <20200422112719.826676174@infradead.org> <20200422112831.988065598@infradead.org> <20200422132923.GK20730@hirez.programming.kicks-ass.net> <20200422135921.GL20730@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 22, 2020 at 05:09:15PM +0200, Vincent Guittot wrote: > > It's not unbounded, like a true idle-time scheduler would be, but it can > > still be pretty horrible. nice19 has some of that too of course, but > > idle has it worse, esp. also because it begs others to preempt it. > > Yeah... you have to pay the benefit of letting other tasks to preempt > faster. But both sched_idle and nice19 have the same weight #define WEIGHT_IDLEPRIO 3 /* 15 */ 36, 29, 23, 18, 15, 15 != 3 Also, like said elsewhere, idle is much more eager to let itself be preempted.