Re: [Gems-users] Invalidate directory entry

["Lei Yang" <lya755@xxxxxxxxxxxxxxxxxxxx>]

Mike, Thanks for your prompt reply. So there is actually no directory stored 
on each chip to keep the state of a memory address?
Lei
----- Original Message ----- 
From: "Mike Marty" <mikem@xxxxxxxxxxx>
To: "Lei Yang" <lya755@xxxxxxxxxxxxxxxxxxxx>; "Gems Users" 
<gems-users@xxxxxxxxxxx>
Sent: Wednesday, January 10, 2007 4:59 PM
Subject: Re: [Gems-users] Invalidate directory entry


> This protocol stores the directory state in the L2 cache tag.  The
> L2_Replacement will eventually cause the L2 controller to deallocate the
> L2 cache tag.  When both the TBE (for handling the replacement of shared
> or dirty data) and the L2 tag is deallocated, then the Directory state is
> gone and considered NP (Not Present), equivalent to I.
>
> For example, replacing M will deallocate L2 tag immediately but allocate a
> TBE (to handle the demand miss causing the replacement in parallel).
> Eventually this transition occurs, which will actually result in state NP
> (Not Present) even though the target transition state is L2_I.  If there
> is nothing to hold the state L2_I, then the state is L2_NP
>
>  transition(L2_MIN, Dir_WB_ack, L2_I) {
>    s_deallocateTBE;
>    l_popForwardedRequestQueue;
>  }
>
>
> That was a confusing explanation.
>
> --Mike
>
>
> > Hi list, >
> > I'm looking at MSI_MOSI_CMP_directory-L2cache.sm file and I'm wondering 
> > after a L2_Replacement, where/how did the protocol change the state of 
> > the corresponding directory entry to invalidate that? Please advise.
> > Thanks,
> > Lei