From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932774Ab0KSWL6 (ORCPT ); Fri, 19 Nov 2010 17:11:58 -0500 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.125]:63407 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932711Ab0KSWLv (ORCPT ); Fri, 19 Nov 2010 17:11:51 -0500 X-Authority-Analysis: v=1.1 cv=6ptpMFIBtxRk0xdOb6IhJTbTLVRlKjWFes7R4SsWCrA= c=1 sm=0 a=7c-JFGxozsUA:10 a=bbbx4UPp9XUA:10 a=OPBmh+XkhLl+Enan7BmTLg==:17 a=pGLkceISAAAA:8 a=meVymXHHAAAA:8 a=2rs2RijT8D-jbCgwNtgA:9 a=QYSxkNT07ikeMSyrh1cA:7 a=ejenB99CELfE48ECfLhhg6XBvjUA:4 a=MSl-tDqOz04A:10 a=jeBq3FmKZ4MA:10 a=OPBmh+XkhLl+Enan7BmTLg==:117 X-Cloudmark-Score: 0 X-Originating-IP: 67.242.120.143 Message-Id: <20101119221148.271352565@goodmis.org> User-Agent: quilt/0.48-1 Date: Fri, 19 Nov 2010 17:11:23 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Thomas Gleixner , Frederic Weisbecker , Michal Marek , Wu Zhangjin Subject: [PATCH 1/2] ftrace: Speed up recordmcount References: <20101119221122.946280474@goodmis.org> Content-Disposition: inline; filename=0001-ftrace-Speed-up-recordmcount.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Wu Zhangjin cmd_record_mcount is used to locate the _mcount symbols in the object files, only the files compiled with -pg has the _mcount symbol, so, it is only needed for such files, but the current cmd_record_mcount is used for all of the object files, so, we need to fix it and speed it up. Since -pg may be removed by the method used in kernel/trace/Makefile: ORIG_CFLAGS := $(KBUILD_CFLAGS) KBUILD_CFLAGS = $(subst -pg,,$(ORIG_CFLAGS)) Or may be removed by the method used in arch/x86/kernel/Makefile: CFLAGS_REMOVE_file.o = -pg So, we must check the last variable stores the compiling flags, that is c_flags(Please refer to cmd_cc_o_c and rule_cc_o_c defined in scripts/Makefile.build) and since the CFLAGS_REMOVE_file.o is already filtered in _c_flags(Please refer to scripts/Makefile.lib) and _c_flags has less symbols, therefore, we only need to check _c_flags. --------------- Changes from v1: o Don't touch Makefile for CONFIG_FTRACE_MCOUNT_RECORD is enough o Use _c_flags intead of KBUILD_CFLAGS to cover CONFIG_REMOVE_file.o = -pg (feedback from Steven Rostedt ) Acked-by: Michal Marek Signed-off-by: Wu Zhangjin LKML-Reference: <3dc8cddf022eb7024f9f2cf857529a15bee8999a.1288196498.git.wuzhangjin@gmail.com> [ changed if [ .. == .. ] to if [ .. = .. ] to handle dash environments ] Signed-off-by: Steven Rostedt --- scripts/Makefile.build | 13 +++++++++---- 1 files changed, 9 insertions(+), 4 deletions(-) diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 5ad25e1..4eb99ab 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -214,17 +214,22 @@ ifdef BUILD_C_RECORDMCOUNT # The empty.o file is created in the make process in order to determine # the target endianness and word size. It is made before all other C # files, including recordmcount. -cmd_record_mcount = if [ $(@) != "scripts/mod/empty.o" ]; then \ - $(objtree)/scripts/recordmcount "$(@)"; \ - fi; +sub_cmd_record_mcount = \ + if [ $(@) != "scripts/mod/empty.o" ]; then \ + $(objtree)/scripts/recordmcount "$(@)"; \ + fi; else -cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \ +sub_cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \ "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \ "$(if $(CONFIG_64BIT),64,32)" \ "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CFLAGS)" \ "$(LD)" "$(NM)" "$(RM)" "$(MV)" \ "$(if $(part-of-module),1,0)" "$(@)"; endif +cmd_record_mcount = \ + if [ "$(findstring -pg,$(_c_flags))" = "-pg" ]; then \ + $(sub_cmd_record_mcount) \ + fi; endif define rule_cc_o_c -- 1.7.1