Re: [parisc-linux] sched_clock implementation

[Joel Soete <soete.joel@tiscali.be>]

Carlos O'Donell wrote:

>On Fri, Sep 19, 2003 at 03:32:41PM +0000, Joel Soete wrote:
>  
>
>>Matthew Wilcox wrote:
>>
>>    
>>
>>>Anyone want to do better than the lame implementation?  ;-)
>>>
>>>----- Forwarded message from Andrew Morton <akpm@osdl.org> -----
>>>
>>>I'll be merging Ingo & Con's CPOU scheduler changes into Linus's tree soon.
>>>
>>>It does require that the architecture provides a new timing function:
>>>
>>>A lame implementation is:
>>>
>>>/*
>>>* Returns nanoseconds
>>>*/
>>>
>>>
>>>      
>>>
>>Hi Willy,
>>
>>(Certainly yet another stupid question but) to reach such accuracy we 
>>would need to have access to some 'time device' with an accuracy better 
>>then the nanosec (iirc 10^-9) (because it doesn't seems to me possible 
>>to get enough accuracy with cpu clock < 10^9 ie 1Ghz: the most case for 
>>parisc systems). Does it exist such device and where to start to read 
>>some doc?
>>    
>>
>
>We could use cr16 to get better accuracy. See list discussions about
>fast gettimeofday.
>
>c.
>
Hi all,

a quick look into paxx.pdf which about CR16 speak of "peak instruction 
rate" but do not define anywhere?
I presume that is the cpu clock but would like somebody confirm.

Thanks in advance,
    Joel