[PATCH v3] printk: add option to print cpu id

[Pandita, Vikram]

On Fri, Aug 3, 2012 at 2:59 PM, Greg KH <gregkh at linuxfoundation.org> wrote:
> On Fri, Aug 03, 2012 at 02:24:20PM -0700, Pandita, Vikram wrote:
>> Aaro
>>
>> On Fri, Aug 3, 2012 at 1:08 PM, Aaro Koskinen <aaro.koskinen at iki.fi> wrote:
>> > Hi,
>> >
>> > On Fri, Aug 03, 2012 at 11:25:37AM -0700, Pandita, Vikram wrote:
>> >> > And really: Wasting 1/3 of the 80 character line is too much.
>> >>
>> >> You _WASTE_ 4 chars only if you are interested in this info by
>> >> enabling: CONFIG_PRINTK_CPUID
>> >
>> > I guess you waste 4 + 3 chars? You could optimize the length by checking
>> > CONFIG_NR_CPUS?
>>
>> Good point.
>> Looks there is a variable 'nr_cpu_ids' that could be used as well.
>>
>> If there is general consensus that the patch can help the arm
>> community, and others in general,
>> this optimization should be easy to implement - saving few chars space
>> in each line of console output.
>>
>> For now i will stick to this v3 version of path, unless you think otherwise.
>
> I don't think is is something that anyone needs, and if you do, as
> pointed out, you can use the trace function to make it happen.
>

This was something that got used internally and helped at times.
This attempt to give back to community, but i understand the rationale to go
with larger consensus.

At least the patch is out there in public for anyone to make use of.

> Adding features are not "free", someone has to maintain them and all of
> the other work involved with it.  So don't just think that because it is
> hidden behind a config option, that it doesn't affect people.

At least the v3 patch is a complete working implementation wrt
kernel/printk.c file
as it exists on linus tree master today.

Understand long term this does have maintenance overhead just like
printk_time does.

>
> greg k-h