Huge difference in build sizes

[Vinícius Tinti]

On Tue, Dec 2, 2014 at 10:50 AM, Vinícius Tinti <viniciustinti at gmail.com> wrote:
> On Tue, Dec 2, 2014 at 10:37 AM, Raghavendra <arrao at cdac.in> wrote:
>> Hello Tinti,
>>
>> Thank you for the reply.
>>
>> On Tuesday 02 December 2014 05:21 PM, Vinícius Tinti wrote:
>>>
>>> On Tue, Dec 2, 2014 at 7:08 AM, Raghavendra <arrao at cdac.in> wrote:
>>>>
>>>> Hello all,
>>>>
>>>> I am using Ubuntu-12.04 which came with 3.2 kernel. Parallel to this,
>>>> I've compiled and installed 3.12.1 kernel using the Ubuntu-3.2's
>>>> configuration, and the compiler which came with the distro. I've noticed
>>>> that there is a huge difference in the size of the .ko file between the
>>>> Ubuntu's kernel and the kernel which I've compiled. Sample results are :
>>>>
>>>> $ du -sh usb-storage.ko
>>>> It shows : 56K for the Ubuntu's 3.2 kernel
>>>>                   1.3M for the custom kernel that I've compiled
>>>>
>>>> I've tested the same thing for a simple hello world module :
>>>> $ du -sh hello.ko
>>>> It shows : 4.0k for the Ubuntu's 3.2 kernel
>>>>                   56k for the custom kernel that I've compiled
>>>>
>>>> What could be the reason for this huge amount of difference of storage
>>>> space in spite of using the same config file and compiler?
>>>
>>> Are you sure that you have build with the same optimization flags?
>>>
>>> I guess that "-O2" is missing in the big example. Could you double check?
>>
>> Actually, I haven't use any optimization flags. I've just hit 'make' from
>> the command line while compiling for both the kernels. I even checked the
>> Makefile of both the kernels. -O2 flag is used in the same way in both the
>> Makefiles.
>
> Strange. Can you try this?

Opps.
http://stackoverflow.com/questions/1999654/how-can-i-tell-if-a-library-was-compiled-with-g

Maybe there are debug symbols in one of the kernels. Dunno.

>
>> Regards,
>> Raghavendra
>>
>>>
>>> Regards
>>>
>>>> Thanks in advance.
>>>>
>>>> Raghavendra
>>>>
>>>>
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>>
>>
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