From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751262AbdKMJXv convert rfc822-to-8bit (ORCPT ); Mon, 13 Nov 2017 04:23:51 -0500 Received: from mout.gmx.net ([212.227.15.18]:52024 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750983AbdKMJXu (ORCPT ); Mon, 13 Nov 2017 04:23:50 -0500 Message-ID: <1510565015.15042.38.camel@gmx.de> Subject: Re: [GIT PULL] scheduler updates for v4.15 From: Mike Galbraith To: Ingo Molnar , Linus Torvalds Cc: linux-kernel@vger.kernel.org, Peter Zijlstra , Thomas Gleixner , Andrew Morton , Steven Rostedt Date: Mon, 13 Nov 2017 10:23:35 +0100 In-Reply-To: <20171113080054.hvpfoo6bd7ae2yu4@gmail.com> References: <20171113080054.hvpfoo6bd7ae2yu4@gmail.com> Content-Type: text/plain; charset="ISO-8859-15" X-Mailer: Evolution 3.20.5 Mime-Version: 1.0 Content-Transfer-Encoding: 8BIT X-Provags-ID: V03:K0:T33Wvg6f8wACW+ERTQoFwWgC0W4rRJHFfPM8psBdRY/IW0BPswn YE1RPFuSHqICIyUutHBthh1CZYRyGxXW3cfY84B8bcfB2CJjJnMLvufNT517LBSZp/ZCAFA PQLrPL48b9C58u4c0fJzJZbC50jYk/gegqZsLWxgnS5X+WINbN/v5xoL8uJPZ6hZXJhdv2h 2I8jKXKV9DPmhsO/qHcqw== X-UI-Out-Filterresults: notjunk:1;V01:K0:1enMWC42ztM=:MdLHkgmko7obnARdrZDe40 tgAjmWpK7Y3l8LyPSY6UzZuNu5MdTR3/F45aw+YDj4xEjkpz2Zaqd+RFxeuMll3yZOVXL/Tht bgVxVkA7Kz2lXFS0CFbPRbqJz9IEWfRNje3nbZwxpJWO/QCIRYWpWg92sde4DKFFgAwmPpVNf aDa0jnwiaexN7Tx9ruriKE4Ouxr/IyXE1OuVXhTK4KmuLrsXq1rB04Bwdu5EBJHarsiabeZG5 TBljnZU1r9NZY+rbEeTgrIUtPvNyGQmx3qA580EZqGOXKiaCBwsVAGUxr+TRV0lgyZYHrr0l2 3bidljBYICMRT1oudhyn7GVYMUImsnuLihjpqjT252cNPv2bfCRr4/zbqT+oS74EEEOCYGvPP fR/BKmLpWRkmqGrpFIrDd7QvOJ1V0mssD12oSMsW7bxKlf4cwTM/AtGljtLJ4I5kV/nejVv9v tGZhfqjEwmtVnyQv0T2Smz2W+Z87wmFauHaUoQa1RrCLxg+RUbRzlMUpPrDRQeuAujci2s21v Aj5TdynQtqQupxrs50S+sesBxzFyroSzNBTsYJ4CrvYGCsc4oamBwNoLUnHb5NcfY/Ch5dWBB qtCWwCw1rmnXE1+GVpF4mYNXHEREsJ4V4Cz7QgHYUCB4dOPyHwixTcFA7s9JSG2KiJSYEZ5q7 rawwsr6bwXNBg9HN9tB5xOkYzvvtgQ45d+okiK+YAXa7/SL2xFb5XYt2Sr99EPWeqyDOdOGY2 U+oi0hha/6eErWJr/ZuQY8cH2TF5O7WK7Q/SSmjRnR58+KxIPmrqcEKyZehTgCDt/7Y8wShuX kz+4O91r06kRxOS50DbA9L1JfdZ/ofROesw9kevggda5lg65J0= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2017-11-13 at 09:00 +0100, Ingo Molnar wrote: > > - Improve the RT IPI based balancing logic (Steven Rostedt) Well how 'bout that, serendipity strikes again: I just got a report that a proggy Gregory Haskins wrote back in 2007 (preempt-test) was claiming RT was broken, but no, it's every kernel containing b6366f048e0c.  What the proggy does is to start a gaggle of RT tasks of descending priority, giving each an identical quantum of work to do, expecting higher priority tasks to get it done before lower.  That currently does not always happen, we occasionally do not get a task pushed for long enough that a task that should have been preempted by a push shortly after hitting the CPU, manages to remain long enough to finish well before it should have been able to. This patch fixed it up before I could even get my troubleshooting wheels properly smoking (they spin a bit before getting traction).  Given that, not to mention b6366f048e0c being capable of log jamming even fairly modest boxen, perhaps this patch wants a stable tag? -Mike