Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932197Ab1CaFdD (ORCPT ); Thu, 31 Mar 2011 01:33:03 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:53061 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754786Ab1CaFdB convert rfc822-to-8bit (ORCPT ); Thu, 31 Mar 2011 01:33:01 -0400 MIME-Version: 1.0 In-Reply-To: <20110331035511.GA1255@redhat.com> References: <20110329040939.GA32764@redhat.com> <20110331030917.GB26057@redhat.com> <20110331035511.GA1255@redhat.com> From: Linus Torvalds Date: Wed, 30 Mar 2011 22:32:11 -0700 Message-ID: Subject: Re: excessive kworker activity when idle. (was Re: vma corruption in today's -git) To: Dave Jones , Linus Torvalds , Andrew Morton , Linux Kernel , Tejun Heo Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1125 Lines: 27 On Wed, Mar 30, 2011 at 8:55 PM, Dave Jones wrote: > > I tried that, and wasn't particularly enlightened. > > + ? ? ?6.53% ?kworker/1:2 ?[kernel.kallsyms] ?[k] read_hpet > + ? ? ?4.83% ?kworker/0:0 ?[kernel.kallsyms] ?[k] read_hpet Go into those, deeper into the callchain. That's how to see what the upper-level problem is - by seeing who actually calls it. The leafs themselves (where the time is obviously spent) don't tend to be very informative, no. > ?> (Powertop can also do it, and is probably a better thing to use, I'm > ?> just used to "perf record" for other reasons, so..) > > Tried that too, here's what it said.. Hmm. Powertop is _supposed_ to be able to look into the kwork things (it has special trace points for it), but as mentioned, the times I've seen it I've used 'perf', so I haven't actually tried it myself. Linus -- 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/