Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753952Ab3EIVCN (ORCPT ); Thu, 9 May 2013 17:02:13 -0400 Received: from mail-bk0-f49.google.com ([209.85.214.49]:35813 "EHLO mail-bk0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753805Ab3EIVCK (ORCPT ); Thu, 9 May 2013 17:02:10 -0400 MIME-Version: 1.0 In-Reply-To: <20130508203042.GA18895@redhat.com> References: <20130508203042.GA18895@redhat.com> Date: Thu, 9 May 2013 23:02:08 +0200 Message-ID: Subject: Re: rcu_preempt running flat out on idle desktop. From: Frederic Weisbecker To: Dave Jones , paulmck@linux.vnet.ibm.com, Linux Kernel Cc: Ingo Molnar Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2246 Lines: 61 2013/5/8 Dave Jones : > 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 I can't reproduce that issue even with the above setting. Could you please send me your whole config? Thanks. -- 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/