Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753874AbZDVMLc (ORCPT ); Wed, 22 Apr 2009 08:11:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752327AbZDVMLW (ORCPT ); Wed, 22 Apr 2009 08:11:22 -0400 Received: from mx2.redhat.com ([66.187.237.31]:33190 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752087AbZDVMLW (ORCPT ); Wed, 22 Apr 2009 08:11:22 -0400 Subject: Re: [Patch] mm tracepoints update From: Larry Woodman To: Ingo Molnar Cc: KOSAKI Motohiro , =?ISO-8859-1?Q?Fr=E9d=E9ric?= Weisbecker , Li Zefan , Pekka Enberg , eduard.munteanu@linux360.ro, linux-kernel@vger.kernel.org, linux-mm@kvack.org, riel@redhat.com, rostedt@goodmis.org In-Reply-To: <20090422095727.GG18226@elte.hu> References: <1240353915.11613.39.camel@dhcp-100-19-198.bos.redhat.com> <20090422095916.627A.A69D9226@jp.fujitsu.com> <20090422095727.GG18226@elte.hu> Content-Type: text/plain Date: Wed, 22 Apr 2009 08:07:17 -0400 Message-Id: <1240402037.4682.3.camel@dhcp47-138.lab.bos.redhat.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2190 Lines: 57 On Wed, 2009-04-22 at 11:57 +0200, Ingo Molnar wrote: > * KOSAKI Motohiro wrote: > > > > I've cleaned up the mm tracepoints to track page allocation and > > > freeing, various types of pagefaults and unmaps, and critical > > > page reclamation routines. This is useful for debugging memory > > > allocation issues and system performance problems under heavy > > > memory loads. > > > > In past thread, Andrew pointed out bare page tracer isn't useful. > > (do you have a link to that mail?) > > > Can you make good consumer? I will work up some good examples of what these are useful for. I use the mm tracepoint data in the debugfs trace buffer to locate customer performance problems associated with memory allocation, deallocation, paging and swapping frequently, especially on large systems. Larry > > These MM tracepoints would be automatically seen by the > ftrace-analyzer GUI tool for example: > > git://git.kernel.org/pub/scm/utils/kernel/ftrace/ftrace.git > > And could also be seen by other tools such as kmemtrace. Beyond, of > course, embedding in function tracer output. > > Here's the list of advantages of the types of tracepoints Larry is > proposing: > > - zero-copy and per-cpu splice() based tracing > - binary tracing without printf overhead > - structured logging records exposed under /debug/tracing/events > - trace events embedded in function tracer output and other plugins > - user-defined, per tracepoint filter expressions > > I think the main review question is: are they properly structured > and do they expose essential information to analyze behavioral > details of the kernel in this area? > > Ingo > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: email@kvack.org -- 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/