Compile kernel for various times and problem of too long time consuming

[psomas@gentoo.org (Stratos Psomadakis)]

On 08/07/2011 10:48 PM, Amirali Shambayati wrote:
> Would you say how you rebuild kernel?
>
> On Sun, Aug 7, 2011 at 10:34 PM, Randy Dunlap <rdunlap@xenotime.net> wrote:
>> On Sun, 7 Aug 2011 21:39:12 +0430 Amirali Shambayati wrote:
>>
>>> Hi all,
>>> Since I want to evaluate performance improvements by changing just one
>>> file in kernel(noop-iosched) and compiling kernel is too much
>>> time-consuming, I want to know that if I compile kernel for more than
>>> one time, does it take similar time to first time?
>>>
>>> I use following commands. If I don't use "make-kpkg clean" for next
>>> times, does it just compile the files which have been modified or it
>>> compile whole kernel package again?
>>>
>>> make-kpkg clean
>>> fakeroot make-kpkg --initrd --append-to-version=-some-string-here
>>> kernel-image kernel-headers
>> Since I never use make-kpkg, I can only tell you that when I modified
>> block/noop-iosched.c and rebuilt the kernel, here is what was rebuilt:
>>
>>  GEN     /lnx/src/NEXT/linux-next-20110805/X32/Makefile
>>  CHK     include/linux/version.h
>>  Using /lnx/src/NEXT/linux-next-20110805 as source for kernel
>>  CHK     include/generated/utsrelease.h
>>  CALL    /lnx/src/NEXT/linux-next-20110805/scripts/checksyscalls.sh
>>  CHK     include/generated/compile.h
>>  CHK     kernel/config_data.h
>>  CC      block/noop-iosched.o
>>  LD      block/built-in.o
>>  LD      vmlinux.o
>>  MODPOST vmlinux.o
>>  GEN     .version
>>  CHK     include/generated/compile.h
>>  UPD     include/generated/compile.h
>>  CC      init/version.o
>>  LD      init/built-in.o
>>  LD      .tmp_vmlinux1
>>  KSYM    .tmp_kallsyms1.S
>>  AS      .tmp_kallsyms1.o
>>  LD      .tmp_vmlinux2
>>  KSYM    .tmp_kallsyms2.S
>>  AS      .tmp_kallsyms2.o
>>  LD      vmlinux
>>  SYSMAP  System.map
>>  SYSMAP  .tmp_System.map
>>  Building modules, stage 2.
>>  VOFFSET arch/x86/boot/voffset.h
>>  CC      arch/x86/boot/version.o
>>  OBJCOPY arch/x86/boot/compressed/vmlinux.bin
>>  LZMA    arch/x86/boot/compressed/vmlinux.bin.lzma
>>  MODPOST 575 modules
>>  MKPIGGY arch/x86/boot/compressed/piggy.S
>>  AS      arch/x86/boot/compressed/piggy.o
>>  LD      arch/x86/boot/compressed/vmlinux
>>  ZOFFSET arch/x86/boot/zoffset.h
>>  OBJCOPY arch/x86/boot/vmlinux.bin
>>  AS      arch/x86/boot/header.o
>>  LD      arch/x86/boot/setup.elf
>>  OBJCOPY arch/x86/boot/setup.bin
>>  BUILD   arch/x86/boot/bzImage
>> Setup is 14972 bytes (padded to 15360 bytes).
>> System is 1287 kB
>> CRC 64ecf4d
>> Kernel: arch/x86/boot/bzImage is ready  (#18)
>>
>>
>> so it's a minimal rebuild, not a full kernel rebuild.
>>
>> ---
>> ~Randy
>> *** Remember to use Documentation/SubmitChecklist when testing your code ***
>>
just run a make at the toplevel kernel sources directory...if you change
just one file, make won't rebuild everything, just what it needs to be
rebuilt and 'relinked'...

you're rebuilding the whole kernel every time, because you're running
make-pkg clean, which I think runs make clean and cleans every object
file you've built so far...

-- 
Stratos Psomadakis
<psomas@gentoo.org>


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