Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753658AbZJZQo6 (ORCPT ); Mon, 26 Oct 2009 12:44:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752847AbZJZQo5 (ORCPT ); Mon, 26 Oct 2009 12:44:57 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.123]:50839 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751499AbZJZQo4 (ORCPT ); Mon, 26 Oct 2009 12:44:56 -0400 Subject: Re: [PATCH -v6 07/13] tracing: add dynamic function tracer support for MIPS From: Steven Rostedt Reply-To: rostedt@goodmis.org To: wuzhangjin@gmail.com Cc: linux-mips@linux-mips.org, linux-kernel@vger.kernel.org, Frederic Weisbecker , Thomas Gleixner , Ralf Baechle , Richard Sandiford , Nicholas Mc Guire , David Daney , Adam Nemet , Patrik Kluba In-Reply-To: <1256574910.5642.228.camel@falcon> References: <747deea2f18d5ccffe842df95a9dd1c86251a958.1256569489.git.wuzhangjin@gmail.com> <3f47087b70a965fd679b17a59521671296457df1.1256569489.git.wuzhangjin@gmail.com> <07dc907ec62353b1aca99b2850d3b2e4b734189a.1256569489.git.wuzhangjin@gmail.com> <374da7039d2e1b97083edd8bcd7811356884d427.1256569489.git.wuzhangjin@gmail.com> <3c82af564d70be05b92687949ed134ce034bf8db.1256569489.git.wuzhangjin@gmail.com> <1256573175.26028.310.camel@gandalf.stny.rr.com> <1256574910.5642.228.camel@falcon> Content-Type: text/plain Organization: Kihon Technologies Inc. Date: Mon, 26 Oct 2009 12:45:00 -0400 Message-Id: <1256575500.26028.323.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: 943 Lines: 24 On Tue, 2009-10-27 at 00:35 +0800, Wu Zhangjin wrote: > If remove the long jump, we at least to change the $mcount_regex in > scripts/recordmcount.pl, the addr + 12 in arch/mips/include/asm/ftrace.h > and the _mcount & ftrace_caller in mcount.S and the ftrace_make_nop & > ftrace_make_call in arch/mips/kernel/ftrace.c back to the -v4 version. > > I think this method of supporting module is not that BAD, no obvious > overhead added except the "lui...addiu..." and two more "nop" > instructions. and it's very understandable, so, just use this version? You don't nop the lui and addiu do you? If you do you will crash the machine. As for overhead, you might want to test that out. -- Steve -- 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/