Minimal Kernel Config for a F14 KVM guest

[Eamon Walsh]

On 07/01/2011 11:49 AM, David Quigley wrote:
>  On Fri, 01 Jul 2011 16:01:32 +0100, agraham wrote:
>> On 07/01/2011 04:12 AM, Dave Quigley wrote:
>>> Hello,
>>>      I will be teaching a one day class in a few weeks and I am 
>>> going to
>>> have the students do some kernel programming. Since it is only a one 
>>> day
>>> course I need to pack as much info into it as possible so I would 
>>> like
>>> to minimize the build times as much as possible. The modifications 
>>> that
>>> they will be making will be touching core kernel headers so it will 
>>> have
>>> to rebuild almost all of the kernel every time. Because of this I'd 
>>> like
>>> to get a kernel config that can get F14 booting (the minimal 
>>> install) in
>>> KVM with the shortest build time possible. I've gotten the build 
>>> down to
>>> 9 minutes and 55 seconds but I would like it sub 5 minutes. Does 
>>> anyone
>>> have or know of a place where I can find a bare minimum config. I've
>>> been working on trimming down the stock F14 kernel but there is so 
>>> much
>>> to go through I'm thinking it might be best to build it up from an
>>> allnoconfig instead.
>>>
>>> Dave
>> When making the kernel use make -j8 (assuming you have 8 cores) that
>> should reduce your time by running 8 parallel processes, in addition,
>> install ccache, that only compiles the code if it has changed or is
>> dependant on some other change, this should result in recompile of 
>> only
>> a few mins.
>>
>> Albert.
>  I doubt that people will be allocating 8 cores to a VM. I have 2 cores 
>  and 1GB of memory allocated at the moment and use -j3 to compile. The 
>  problem is they will be touching security.h which in one way or another 
>  is pretty much included by every source file in the Linux kernel so 
>  ccache won't be of much help (my normal dev box has ccache installed and 
>  it doesn't save me much time). The biggest way to cut down on time seems 
>  to be remove all the drivers that I can from being built. I think I have 
>  this almost complete. It would be nice if there was a make kvmconfig 
>  which gave you the base for an x86 or x86_64 kvm kernel config and then 
>  you can turn on whatever else you want filesystem and driver wise for 
>  passthrough devices.
>
>  Dave
>

Maybe you could try building allmodconfig, then boot the kernel and lsmod to see what has been loaded.  Then disable everything except for those modules.

--Eamon


-- 

Eamon Walsh 
National Security Agency