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 621C2C74A5B for ; Wed, 29 Mar 2023 08:20:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230483AbjC2IUb (ORCPT ); Wed, 29 Mar 2023 04:20:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46734 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230449AbjC2IUB (ORCPT ); Wed, 29 Mar 2023 04:20:01 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C0858526E for ; Wed, 29 Mar 2023 01:18:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.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=GjB9ZbCegMQhM5Q6LjfEh62fnlRUwmV++cEbAcHP2BI=; b=oM4lCOywwCWUrFGLg8ZghL1wvo kKoleikexrSL8RKjSRDfc6Ne+OI/CusTeNuNKcE4Yv3qzFl20jyzd/yqej5zI59o07XKu5JBMsdIW OXey2ZRG41zU1eq6XO/lYbIMK14FOQalgPZyk+XfF2ZUOzopEI2zG6SgdJ3OGLk1NBRTOm47UWkTV OH1JW/hiBxh9zb0Wdgr0CZhb8pfU9exdcVWgJsONZOQ42X0Ol8katRmECElxvGFjvsFjRkkSM0SgY q4rzKbbtE3sq22CDLiDjplPQ4mKPZD1RXfSFhPMUk+6NV+kOn3vwCIlh2kkXVpIAjKxgdbTfHIDFi 1E2OKCow==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1phR0Z-009Exi-RK; Wed, 29 Mar 2023 08:18:15 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 527FB3002A3; Wed, 29 Mar 2023 10:18:14 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 348F02CB94EE8; Wed, 29 Mar 2023 10:18:14 +0200 (CEST) Date: Wed, 29 Mar 2023 10:18:14 +0200 From: Peter Zijlstra To: Josh Don Cc: mingo@kernel.org, vincent.guittot@linaro.org, linux-kernel@vger.kernel.org, juri.lelli@redhat.com, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, corbet@lwn.net, qyousef@layalina.io, chris.hyser@oracle.com, patrick.bellasi@matbug.net, pjt@google.com, pavel@ucw.cz, qperret@google.com, tim.c.chen@linux.intel.com, timj@gnu.org, kprateek.nayak@amd.com, yu.c.chen@intel.com, youssefesmat@chromium.org, joel@joelfernandes.org, efault@gmx.de Subject: Re: [PATCH 08/17] sched/fair: Implement an EEVDF like policy Message-ID: <20230329081814.GN4253@hirez.programming.kicks-ass.net> References: <20230328092622.062917921@infradead.org> <20230328110354.141543852@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 28, 2023 at 06:26:51PM -0700, Josh Don wrote: > Hi Peter, > > This is a really interesting proposal and in general I think the > incorporation of latency/deadline is quite a nice enhancement. We've > struggled for a while to get better latency bounds on performance > sensitive threads in the face of antagonism from overcommit. Right; so the big caveat is of course that these are virtual deadlines, overcommit *will* push them out. We have SCHED_DEADLINE that does the 'real' deadline thing ;-) But what these virtual deadlines do is provide an order inside the virtual time domain. It makes the whole preemption business well defined. And with that, provides means to mix varying request sizes.