Rep:Re: spinlocks (was Re: [f-cpu] another DATE report)

["Nicolas Boulay" <nicolas.boulay@ifrance.com>]

-----Message d'origine-----
De: Juergen Goeritz <goeritz@oekomm.de>
A: f-cpu@seul.org
Date: 19/03/02
Objet: Re: spinlocks (was Re: [f-cpu] another DATE report)

On Mon, 18 Mar 2002, Michael Riepe wrote:

> On Mon, Mar 18, 2002 at 12:41:41PM +0100, Yann Guidon wrote:
> > hello,
> > 
> > Christophe wrote:
> > > > We could easily do this kind of operation in hardware, btw.
> > > Oh fine.
> > 
> > just a question : "how" ?
> 
>  repeat
>   pull the requested memory location into the cache
>   make the executing CPU the owner of the cache line (SMP)

Ain't that exactly the problem? How do you become exclusive owner?

>>> Thats why the bus that we used must have CAS2 cycle and there is no
more problem. Shared or not shared data information should only be used
to manage caches.
nicO


>   read data and compare
>   if (the line is still valid and owned by us)
>    if (the result was true)
>     write data
>    end if
>    return (result)
>   end if
>  end repeat

JG

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