Re: How to compose kernel makeoptions

[charles <charles.westerman%gmail.com@localhost>]

so why doesn't the GENERIC kernel config use the -march-native and/i think
use march486?

On Fri, Feb 25, 2011 at 8:53 PM, charles 
<charles.westerman%gmail.com@localhost>wrote:

> ha, i yearn for the time when i'm tasked to eek the last bit of process.
>
> so man cc, cool thanks chuck.
>
> that "info" thing still perplexes me, i don't get it.
>
> anyway thanks for your help, right on.
>
> charles
>
>
> On Fri, Feb 25, 2011 at 8:38 PM, Chuck Swiger <cswiger%mac.com@localhost> 
> wrote:
>
>> On Feb 25, 2011, at 5:25 PM, charles wrote:
>> > so i guess i can ignore/not worry about the makeoptions line in the
>> config or/and add "-march=pentium3"
>> >
>> > and if that's so ... well it was strange to see the new option as a
>> makeoption instead of what is was before, so i'm making something out of
>> nothing perhaps.
>>
>> Well, you're welcome to try your own benchmarks and see for yourself
>> whether there is a meaningful difference for your workload.  :-)
>>
>> > where do i find the march definitions? is there a master list?
>>
>> -march=native is easier than processing the whole list, but "man cc" (or
>> "info gcc", perhaps) will give you a huge long list which starts:
>>
>>           i386
>>               Original Intel's i386 CPU.
>>
>>           i486
>>               Intel's i486 CPU.  (No scheduling is implemented for this
>> chip.)
>>
>>           i586, pentium
>>               Intel Pentium CPU with no MMX support.
>>
>>           pentium-mmx
>>               Intel PentiumMMX CPU based on Pentium core with MMX
>> instruction
>>               set support.
>>
>>           pentiumpro
>>               Intel PentiumPro CPU.
>>
>>           i686
>>               Same as "generic", but when used as "march" option,
>> PentiumPro
>>               instruction set will be used, so the code will run on all
>> i686
>>               family chips.
>>
>>           pentium2
>>               Intel Pentium2 CPU based on PentiumPro core with MMX
>> instruc-
>>               tion set support.
>>
>>           pentium3, pentium3m
>>               Intel Pentium3 CPU based on PentiumPro core with MMX and SSE
>>               instruction set support.
>> [ ...and then wanders off into P4/Prescott/Nocona, AMD Athlon/Opteron, VIA
>> C3, etc... ]
>>
>> Regards,
>> --
>> -Chuck