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Message-ID: <AANLkTikxQxCYHEe5bJCx9dNY6AZNpVBgHLxp99+MbzgH@mail.gmail.com>
Date: Wed, 27 Oct 2010 22:39:45 +0800
From: wu zhangjin <wuzhangjin@...il.com>
To: Steven Rostedt <rostedt@...dmis.org>
Cc: linux-kernel@...r.kernel.org, mingo@...e.hu,
John Reiser <jreiser@...wagon.com>,
Michal Marek <mmarek@...e.cz>,
linux-kbuild <linux-kbuild@...r.kernel.org>,
Sam Ravnborg <sam@...nborg.org>
Subject: Re: [PATCH] ftrace: Speed up recordmcount
On Wed, Oct 27, 2010 at 9:21 PM, Steven Rostedt <rostedt@...dmis.org> wrote:
> [ Added kbuild maintainers ]
>
> On Wed, 2010-10-27 at 18:39 +0800, Wu Zhangjin wrote:
>> From: Wu Zhangjin <wuzhangjin@...il.com>
>>
>> cmd_record_mcount is only needed for the targets who are compiled with
>> -pg, so, only define it when CONFIG_FTRACE_MCOUNT_RECORD is defined and
>> only use it for the targets who are compiled with -pg.
>
> Thanks! I was going to do this myself, but just have not gotten around
> to it.
When I found the C version of recordmcount tried to cope with the
files under arch/mips/boot/compressed/, I felt a little nervous and
tried to fix it ;-)
>
>>
>> Signed-off-by: Wu Zhangjin <wuzhangjin@...il.com>
>
> I need a SoB from Michal to apply it.
>
>> ---
>> Makefile | 11 ++++++++---
>> scripts/Makefile.build | 26 ++++++++++++++++----------
>> 2 files changed, 24 insertions(+), 13 deletions(-)
>>
>> diff --git a/Makefile b/Makefile
>> index 3e43805..60d7a87 100644
>> --- a/Makefile
>> +++ b/Makefile
>> @@ -576,9 +576,14 @@ endif
>> ifdef CONFIG_FUNCTION_TRACER
>> KBUILD_CFLAGS += -pg
>> ifdef CONFIG_DYNAMIC_FTRACE
>> - ifdef CONFIG_HAVE_C_RECORDMCOUNT
>> - BUILD_C_RECORDMCOUNT := y
>> - export BUILD_C_RECORDMCOUNT
>> + ifdef CONFIG_FTRACE_MCOUNT_RECORD
>
> FTRACE_MCOUNT_RECORD depends on DYNAMIC_FTRACE, so if you require
> FTRACE_MCOUNT_RECORD, you can remove the ifdef CONFIG_DYNAMIC_FTRACE.
ok, will remove it.
>
>
>> + DEFINE_CMD_RECORD_MCOUNT := y
>> + export DEFINE_CMD_RECORD_MCOUNT
>> +
>> + ifdef CONFIG_HAVE_C_RECORDMCOUNT
>> + BUILD_C_RECORDMCOUNT := y
>> + export BUILD_C_RECORDMCOUNT
>> + endif
>> endif
>> endif
>> endif
>> diff --git a/scripts/Makefile.build b/scripts/Makefile.build
>> index 5ad25e1..ceb5175 100644
>> --- a/scripts/Makefile.build
>> +++ b/scripts/Makefile.build
>> @@ -208,22 +208,28 @@ cmd_modversions = \
>> fi;
>> endif
>>
>> -ifdef CONFIG_FTRACE_MCOUNT_RECORD
>> +ifdef DEFINE_CMD_RECORD_MCOUNT
>> ifdef BUILD_C_RECORDMCOUNT
>> # Due to recursion, we must skip empty.o.
>> # 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;
>> +cmd_record_mcount = \
>> + if [ "$(findstring -pg,$(KBUILD_CFLAGS))" == "-pg" ]; then \
>> + if [ $(@) != "scripts/mod/empty.o" ]; then \
>> + $(objtree)/scripts/recordmcount "$(@)"; \
>> + fi; \
>> + fi;
>> else
>> -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 $(part-of-module),1,0)" "$(@)";
>> +cmd_record_mcount = \
>> + if [ "$(findstring -pg,$(KBUILD_CFLAGS))" == "-pg" ]; then \
>> + 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 $(part-of-module),1,0)" "$(@)"; \
>> + fi;
>> endif
>> endif
>>
>
>
> Note, this does not catch objects that have the -pg stripped by
> CFLAGS_REMOVE_object.o
Just checked the scripts/Makefile.lib and found c_flags:
106 _c_flags = $(filter-out $(CFLAGS_REMOVE_$(basetarget).o),
$(orig_c_flags))
And after used it instead of KBUILD_CFLAGS, it works well. Here is the
testing result:
1. The normal files with -pg
$ make ARCH=mips CROSS_COMPILE=mips64el-unknown-linux-gnu- -j5 init/main.o
CHK include/linux/version.h
CHK include/generated/utsrelease.h
Checking missing-syscalls for N32
CALL scripts/checksyscalls.sh
Checking missing-syscalls for O32
CALL scripts/checksyscalls.sh
CALL scripts/checksyscalls.sh
CC init/main.o
****printed by scripts/recordmcount.c: main
2. the files with CONFIG_REMOVE_file.o = -pg
$ make ARCH=mips CROSS_COMPILE=mips64el-unknown-linux-gnu- -j5
arch/mips/kernel/ftrace.o
CHK include/linux/version.h
CHK include/generated/utsrelease.h
Checking missing-syscalls for N32
CALL scripts/checksyscalls.sh
Checking missing-syscalls for O32
CALL scripts/checksyscalls.sh
CALL scripts/checksyscalls.sh
CC arch/mips/kernel/ftrace.o
3. the files with obvious filter of -pg
$ make ARCH=mips CROSS_COMPILE=mips64el-unknown-linux-gnu- -j5
arch/mips/boot/compressed/dbg.o
CHK include/linux/version.h
CHK include/generated/utsrelease.h
Checking missing-syscalls for N32
CALL scripts/checksyscalls.sh
Checking missing-syscalls for O32
CALL scripts/checksyscalls.sh
CALL scripts/checksyscalls.sh
CC arch/mips/boot/compressed/dbg.o
$ make ARCH=mips CROSS_COMPILE=mips64el-unknown-linux-gnu- -j5
kernel/trace/ftrace.o
CHK include/linux/version.h
CHK include/generated/utsrelease.h
Checking missing-syscalls for N32
CALL scripts/checksyscalls.sh
Checking missing-syscalls for O32
CALL scripts/checksyscalls.sh
CALL scripts/checksyscalls.sh
CC kernel/trace/ftrace.o
>
>
> How about something like this:
>
> ifdef DEFINE_CMD_RECORD_MCOUNT
> ifdef BUILD_C_RECORDMCOUNT
> sub_cmd_record_mcount = if [ $(@) != "scripts/mod/empty.o" ]; then \
> $(objtree)/scripts/recordmcount "$(@)"; \
> fi;
> else
> 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
>
>
>
> I tested the above and it seemed to work (although, I did it on another
> machine, and copied it here by hand, so this version may have a typo).
>
Yeah, this removed the duplicated findstring, will fix the typo and apply it.
Thanks!
Wu Zhangjin
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