svn commit: r314669 - head/sys/i386/conf

[Pedro Giffuni]

On 03/04/17 10:32, Slawa Olhovchenkov wrote:
> On Sat, Mar 04, 2017 at 03:04:17PM +0000, Pedro F. Giffuni wrote:
>
>> Author: pfg
>> Date: Sat Mar  4 15:04:17 2017
>> New Revision: 314669
>> URL: https://svnweb.freebsd.org/changeset/base/314669
>>
>> Log:
>>   Drop i486 from the default i386 GENERIC kernel configuration.
>>
>>   80486 production was stopped by Intel on September 2007. Dropping the 486
>>   configuration option from the GENERIC kernel improves performance
>>   slightly.
>>
>>   Removing I486_CPU is consistent at this time: we don't support any
>>   processor without a FPU and the PC-98 arch, which frequently involved i486
>>   CPUs, is also gone so we don't test such platforms anymore.
>
> What is realy mean?

This means we don't do work-arounds that would be required for raw 486.
Instead we will use the 586 instructions by default.

> Some Via CPU is like i486 (by instruction set).
>
> CPU: VIA Ezra (800.04-MHz 686-class CPU)
>   Origin="CentaurHauls"  Id=0x678  Family=0x6  Model=0x7  Stepping=8
>   Features=0x803035<FPU,DE,TSC,MSR,MTRR,PGE,MMX>
>   AMD Features=0x80000000<3DNow!>
>

486 never had MMX extensions.
This is a 686, performance should improve ~4%.

Pedro.