Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756262AbXJBWeS (ORCPT ); Tue, 2 Oct 2007 18:34:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752995AbXJBWeJ (ORCPT ); Tue, 2 Oct 2007 18:34:09 -0400 Received: from mx1.redhat.com ([66.187.233.31]:58930 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751300AbXJBWeH (ORCPT ); Tue, 2 Oct 2007 18:34:07 -0400 Message-ID: <4702C756.8090108@redhat.com> Date: Tue, 02 Oct 2007 18:33:58 -0400 From: Chuck Ebbert Organization: Red Hat User-Agent: Thunderbird 1.5.0.12 (X11/20070719) MIME-Version: 1.0 To: Andrew Morton CC: =?ISO-8859-1?Q?Anders_Bostr=F6m?= , linux-kernel@vger.kernel.org, arjan@linux.intel.com, torvalds@linux-foundation.org Subject: Re: PROBLEM: high load average when idle References: <20071002.233731.119908363.anders@bostrom.dyndns.org> <20071002150748.906970bc.akpm@linux-foundation.org> In-Reply-To: <20071002150748.906970bc.akpm@linux-foundation.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2478 Lines: 56 On 10/02/2007 06:07 PM, Andrew Morton wrote: > On Tue, 02 Oct 2007 23:37:31 +0200 (CEST) > Anders Bostr__m wrote: > >> My computer suffers from high load average when the system is idle, >> introduced by commit 44d306e1508fef6fa7a6eb15a1aba86ef68389a6 . >> >> Long story: >> >> 2.6.20 and all later versions I've tested, including 2.6.21 and >> 2.6.22, make the load average high. Even when the computer is totally >> idle (I've tested in single user mode), the load average end up >> at ~0.30. The computer is still responsive, and the only fault seems >> to be the too high load average. All versions up to and including >> 2.6.19.7 is fine, and don't suffer from the problem. >> >> I git bisect between 2.6.19 and 2.6.20 gave me >> 44d306e1508fef6fa7a6eb15a1aba86ef68389a6 "[PATCH] user of the jiffies >> rounding code: JBD" as the first patch with the >> problem. 2.6.20 with 44d306e1508fef6fa7a6eb15a1aba86ef68389a6 reverted >> works fine. 2.6.23-rc8 with 44d306e1508fef6fa7a6eb15a1aba86ef68389a6 >> reverted also works fine. >> >> This fixes the problem: >> >> -------------------------- fs/jbd/transaction.c ----------------------------- >> index cceaf57..d38e0d5 100644 >> @@ -55,7 +55,7 @@ get_transaction(journal_t *journal, transaction_t *transaction) >> spin_lock_init(&transaction->t_handle_lock); >> >> /* Set up the commit timer for the new transaction. */ >> - journal->j_commit_timer.expires = round_jiffies(transaction->t_expires); >> + journal->j_commit_timer.expires = transaction->t_expires; >> add_timer(&journal->j_commit_timer); >> >> J_ASSERT(journal->j_running_transaction == NULL); >> >> >> I've only seen this problem on my home desktop computer. My work >> desktop computer and several other computers at work don't suffer from >> this problem. However, all other computers I've tested on is using >> AMD64 as architecture, and not i386 as my home desktop computer. >> >> Please let me know how I can assist in further debugging of this, if >> needed. > > This is unexpected. High load average is due to either a task chewing a > lot of CPU time or a task stuck in uninterruptible sleep. > Or, everybody wakes up at once right when we are taking a sample. :) - 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/