Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756644Ab3EHUat (ORCPT ); Wed, 8 May 2013 16:30:49 -0400 Received: from mx1.redhat.com ([209.132.183.28]:19060 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755472Ab3EHUas (ORCPT ); Wed, 8 May 2013 16:30:48 -0400 Date: Wed, 8 May 2013 16:30:42 -0400 From: Dave Jones To: paulmck@linux.vnet.ibm.com Cc: Linux Kernel Subject: rcu_preempt running flat out on idle desktop. Message-ID: <20130508203042.GA18895@redhat.com> Mail-Followup-To: Dave Jones , paulmck@linux.vnet.ibm.com, Linux Kernel MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2845 Lines: 58 On what should be an idle desktop, I'm seeing really strange things. The XFCE CPU meter shows both cores are running with no idle time. here's the top of the top(1) output.. PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 10 root 20 0 0 0 0 S 200.0 0.0 185301:36 rcu_preempt 553 root 20 0 268m 76m 6764 S 200.0 2.6 144579:53 Xorg 1199 root 20 0 0 0 0 S 200.0 0.0 306:17.85 kworker/1:0 501 root 20 0 0 0 0 S 200.0 0.0 4471:03 kworker/0:2 12 root 20 0 0 0 0 S 200.0 0.0 67277:16 rcuop/1 1237 davej 20 0 535m 15m 8484 S 200.0 0.5 3645:16 Terminal 859 davej 20 0 117m 3036 1336 S 200.0 0.1 1986:55 htop There are a lot of processes allegedly using "200%" of CPU time, a handful in the "196%" range, and then a bunch at 0. rcu_preempt is staying at the top of the list while everything else bubbles up the list. And what's up with those TIME entries? Box has only been up a few hours, so those numbers look really crazy. RCU options for this build are.. CONFIG_TREE_PREEMPT_RCU=y CONFIG_PREEMPT_RCU=y CONFIG_RCU_STALL_COMMON=y CONFIG_RCU_USER_QS=y CONFIG_RCU_FANOUT=64 CONFIG_RCU_FANOUT_LEAF=16 # CONFIG_RCU_FANOUT_EXACT is not set # CONFIG_RCU_FAST_NO_HZ is not set CONFIG_TREE_RCU_TRACE=y CONFIG_RCU_BOOST=y CONFIG_RCU_BOOST_PRIO=1 CONFIG_RCU_BOOST_DELAY=500 CONFIG_RCU_NOCB_CPU=y CONFIG_RCU_NOCB_CPU_ALL=y CONFIG_DEBUG_OBJECTS_RCU_HEAD=y CONFIG_PROVE_RCU=y # CONFIG_PROVE_RCU_REPEATEDLY is not set CONFIG_PROVE_RCU_DELAY=y CONFIG_SPARSE_RCU_POINTER=y # CONFIG_RCU_TORTURE_TEST is not set CONFIG_RCU_CPU_STALL_TIMEOUT=60 CONFIG_RCU_CPU_STALL_VERBOSE=y # CONFIG_RCU_CPU_STALL_INFO is not set CONFIG_RCU_TRACE=y Dave -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/