Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755734AbZJVPU0 (ORCPT ); Thu, 22 Oct 2009 11:20:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755670AbZJVPUX (ORCPT ); Thu, 22 Oct 2009 11:20:23 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:64993 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756208AbZJVPUT (ORCPT ); Thu, 22 Oct 2009 11:20:19 -0400 Subject: Re: [PATCH -v4 9/9] tracing: add function graph tracer support for MIPS From: Steven Rostedt Reply-To: rostedt@goodmis.org To: wuzhangjin@gmail.com Cc: David Daney , linux-kernel@vger.kernel.org, linux-mips@linux-mips.org, Thomas Gleixner , Ralf Baechle , Nicholas Mc Guire In-Reply-To: <1256218263.3852.115.camel@falcon> References: <028867b99ec532b84963a35e7d552becc783cafc.1256135456.git.wuzhangjin@gmail.com> <2f73eae542c47ac5bbb9f7280e6c0271d193e90d.1256135456.git.wuzhangjin@gmail.com> <3f0d3515f74a58f4cfd11e61b62a129fdc21e3a7.1256135456.git.wuzhangjin@gmail.com> <96110ea5dd4d3d54eb97d0bb708a5bd81c7a50b5.1256135456.git.wuzhangjin@gmail.com> <5dda13e8e3a9c9dba4bb7179183941bda502604f.1256135456.git.wuzhangjin@gmail.com> <53bdfdd95ec4fa00d4cc505bb5972cf21243a14d.1256135456.git.wuzhangjin@gmail.com> <1256141540.18347.3118.camel@gandalf.stny.rr.com> <4ADF38D5.9060100@caviumnetworks.com> <1256143568.18347.3169.camel@gandalf.stny.rr.com> <4ADF3FE0.5090104@caviumnetworks.com> <1256145813.18347.3210.camel@gandalf.stny.rr.com> <1256211516.3852.47.camel@falcon> <1256217444.20866.599.camel@gandalf.stny.rr.com> <1256218263.3852.115.camel@falcon> Content-Type: text/plain Organization: Kihon Technologies Inc. Date: Thu, 22 Oct 2009 11:20:22 -0400 Message-Id: <1256224822.20866.728.camel@gandalf.stny.rr.com> Mime-Version: 1.0 X-Mailer: Evolution 2.26.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1545 Lines: 41 On Thu, 2009-10-22 at 21:31 +0800, Wu Zhangjin wrote: > > If we don't stop at just one save, but look for the saving of ra, it > > should not fail. > > > > We can not look for the saving of ra continuously(when should we stop? When we hit something other than sw .... I'm sure we will get to something other than a store. ;-) > if with -fno-omit-fram-pointer, we have "move s8,sp" or "addiu sp, sp, > -offset", but without it, we have no "guideboard" to know that is the > beginning of the function!), 'Cause we may find the saving of ra of > another function, which will fail at that time. But that other function should have a jump to mcount before it, or some other kind of return. A function that has _mcount attached, can not be inlined. So something must have jumped to it. There should be no cases where code from above just "falls" into the leaf function. > > BTW: Just replace probe_kernel_read() and tracing_stop/tracing_start by > asm, it works in 32bit, but fails in 64bit, I'm trying to find why!(TLB > miss on load or ifetch, will fix it asap! and resend the patchset out!) Thanks! -- Steve Note, I'm going to try booting a vanilla kernel on the notebook. If it works, I'll start applying your patches and playing with it too. But I also have some other work to do first. -- 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/