Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752126AbcKGUAY (ORCPT ); Mon, 7 Nov 2016 15:00:24 -0500 Received: from smtprelay0143.hostedemail.com ([216.40.44.143]:55106 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750905AbcKGUAV (ORCPT ); Mon, 7 Nov 2016 15:00:21 -0500 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Spam-Summary: 2,0,0,,d41d8cd98f00b204,rostedt@goodmis.org,:::::::::::,RULES_HIT:41:355:379:541:599:800:960:973:988:989:1260:1277:1311:1313:1314:1345:1359:1437:1515:1516:1518:1534:1538:1593:1594:1711:1714:1730:1747:1777:1792:2393:2553:2559:2562:2691:2693:3138:3139:3140:3141:3142:3351:3622:3865:3866:3868:3871:3872:3874:4250:5007:6261:7875:10004:10400:10848:10967:11232:11658:11914:12296:12740:12760:13069:13161:13229:13311:13357:13439:14181:14659:14721:21080:30054:30090:30091,0,RBL:none,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fn,MSBL:0,DNSBL:none,Custom_rules:0:0:0,LFtime:2,LUA_SUMMARY:none X-HE-Tag: cake66_8bddfb9ea916 X-Filterd-Recvd-Size: 1742 Date: Mon, 7 Nov 2016 14:47:38 -0500 From: Steven Rostedt To: Christoph Lameter Cc: Daniel Bristot de Oliveira , Ingo Molnar , Peter Zijlstra , linux-rt-users , LKML Subject: Re: [PATCH] sched/rt: RT_RUNTIME_GREED sched feature Message-ID: <20161107144738.4811a5dd@gandalf.local.home> In-Reply-To: References: <20161107133207.4282de69@gandalf.local.home> X-Mailer: Claws Mail 3.14.0 (GTK+ 2.24.31; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 568 Lines: 14 On Mon, 7 Nov 2016 13:30:15 -0600 (CST) Christoph Lameter wrote: > SCHED_RR tasks alternately running on on cpu can cause endless deferral of > kworker threads. With the global effect of the OS processing reserved > it may be the case that the processor we are executing never gets any > time. And if that kworker threads role is releasing a mutex (like the > cgroup_lock) then deadlocks can result. I believe SCHED_RR tasks will still throttle if they use up too much of the CPU. But I still don't see how this patch helps your situation. -- Steve