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Re: spinlocks (was Re: [f-cpu] another DATE report)
On Tue, Mar 19, 2002 at 09:05:02AM +0100, Juergen Goeritz wrote:
> 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?
Cache coherency protocol.
(talking MESI now)
After thinking it over, I guess it's not necessary to get the line into
E state. The only thing we have to check for is whether another CPU
modified the cache line behind our back (which invalidates our copy).
--
Michael "Tired" Riepe <Michael.Riepe@stud.uni-hannover.de>
"All I wanna do is have a little fun before I die"
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