Huge difference in build sizes

[arrao@cdac.in (Raghavendra)]

On Wednesday 03 December 2014 09:45 AM, Greg KH wrote:
> On Wed, Dec 03, 2014 at 09:26:34AM +0530, Raghavendra wrote:
>> Hello Greg,
>>
>> Thank you for the reply.
>>
>> On Tuesday 02 December 2014 11:46 PM, Greg KH wrote:
>>> On Tue, Dec 02, 2014 at 02:38:27PM +0530, Raghavendra 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?
>>> You have not "stripped" the debug symbols from the kernel you built,
>>> which is what Ubuntu does as part of their build process.  I suggest
>>> turning off that kernel configuration option, as it's probably not
>>> needed for your development.
>> If you are referring to the option "CONFIG_DEBUG_INFO", then it is said to
>> 'y' in both the kernel's configuration files.
>> Is there any other config. option or compiler flags that I need to look for?
> That's a good one to turn off, start with that and see what happens.
>
Yeah, I turned off the config option and compared the sizes. Now, both 
result in the same build size. Thanks for the suggestion Greg. Still, my 
concern is that the distro's build is generating a small build size in 
spite of having the option 'CONFIG_DEBUG_INFO' set to 'y'. Any thoughts?

Thanks,
Raghavendra

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