RE: [PATCH] Display Intel Dynamic Acceleration feature in /proc/cpuinfo

Pallipadi, Venkatesh
2007-05-25T00:00:44Z

>-----Original Message-----
>From: H. Peter Anvin [mailto:hpa@zytor.com]
>Sent: Thursday, May 24, 2007 4:23 PM
>To: Pallipadi, Venkatesh
>Cc: Andi Kleen; Dave Jones; Andrew Morton; Brown, Len; linux-kernel
>Subject: Re: [PATCH] Display Intel Dynamic Acceleration
>feature in /proc/cpuinfo
>
>Pallipadi, Venkatesh wrote:
>>
>> Yes. But it only has 3 features defined right now. 2 in EAX
>and one in
>> ECX. Should I use 2 new words for these bits or just use the software
>> defined bits as in my earlier patch?
>>
>
>Oh for heaven's sake. Could you please do the world a favour and shoot
>your CPUID architect?
>
>The real answer depends on how you expect it to grow in the future.
>Intel has a piss-poor record at being consistent in this matter, which
>speaks for a more ad hoc approach, but if there really is a sane growth
>path going forward, then go ahead and define two new words.
>

The way new Intel features are being exposed in CPUID is kind of
changing.
Now we have different CPUID leafs for different kind of features with
each of them growing much slowly.
I mean, there is
monitor-mwait related features in CPUID 5
powermanagement features in CPUID 6 EAX, ECX
Perfmon features in CPUID 10

This does not fit well with the way we use the feature words in Linux.
Probably
it is better to have one new word for new Intel features and add bits
from all
CPUIDs as they come. I will take a look at all the other fields and try
for
a better solution than adding new words for different CPUIDs like above.

Thanks,
Venki