From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757525AbZLXACJ (ORCPT ); Wed, 23 Dec 2009 19:02:09 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755762AbZLXACH (ORCPT ); Wed, 23 Dec 2009 19:02:07 -0500 Received: from acsinet11.oracle.com ([141.146.126.233]:61746 "EHLO acsinet11.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752247AbZLXACG (ORCPT ); Wed, 23 Dec 2009 19:02:06 -0500 Date: Wed, 23 Dec 2009 16:00:50 -0800 From: Randy Dunlap To: Li Zefan Cc: lkml , eduard.munteanu@linux360.ro, Pekka Enberg , Frederic Weisbecker , Ingo Molnar Subject: Re: kmemtrace.txt question: kernel parameter(s)? Message-Id: <20091223160050.0c282ad2.randy.dunlap@oracle.com> In-Reply-To: <4B2AD38D.3070605@cn.fujitsu.com> References: <20091217141342.9ae2072b.randy.dunlap@oracle.com> <4B2AD38D.3070605@cn.fujitsu.com> Organization: Oracle Linux Eng. X-Mailer: Sylpheed 2.7.1 (GTK+ 2.12.0; x86_64-unknown-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Source-IP: acsmt353.oracle.com [141.146.40.153] X-Auth-Type: Internal IP X-CT-RefId: str=0001.0A0B0207.4B32AF5C.0164:SCFMA4539814,ss=1,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 18 Dec 2009 08:57:49 +0800 Li Zefan wrote: > Randy Dunlap wrote: > > Hi, > > > > Documentation/trace/kmemtrace.txt says: > > > > Q: 'cat /sys/kernel/debug/kmemtrace/total_overruns' is non-zero, how do I fix > > this? Should I worry? > > A: If it's non-zero, this affects kmemtrace's accuracy, depending on how > > large the number is. You can fix it by supplying a higher > > 'kmemtrace.subbufs=N' kernel parameter. > > > > > > Where is this kernel parameter implemented and where is it documented? > > or should this Answer just be fixed? > > > > The whole documentation is out-dated. The original kmemtrace was based on > relay, and then it moved to ftrace, without updating the documentation. Thank you. I guess that explains why kmemtraced (from kmemtrace-user.git) fails with: Could not open() file /sys/kernel/debug/kmemtrace/cpu0: No such file or directory Eduard, can we get Documentation/trace/kmemtrace.txt updated, please? --- ~Randy