Re: [Gems-users] Invalidate directory entry

["Lei Yang" <lya755@xxxxxxxxxxxxxxxxxxxx>]

Thanks Mike! That helps a lot. I also added the relationship between L2 and 
directory below for the references of other gems users.
L2 Cache                                                       Directory
----------------------------------------------------------------------------
out: DirRequestFromL2Cache (1)          in: requestToDir (1)
out: finalAckFromL2Cache (4)               in: finalAckToDir (4)
in: forwardedRequestToL2Cache (2)      out: forwardedRequestFromDir (2)
in: responseToL2Cache (3)                     out:  responseFromDir (3)

One more question till I totally understand this, what does "ordered" mean 
for messagebuffers?
Thank you!

Lei

----- Original Message ----- 
From: "Mike Marty" <mikem@xxxxxxxxxxx>
To: "Lei Yang" <lya755@xxxxxxxxxxxxxxxxxxxx>; "Gems Users" 
<gems-users@xxxxxxxxxxx>
Cc: "hongxia sun" <sunhx.seraph@xxxxxxxxx>
Sent: Friday, January 12, 2007 8:36 AM
Subject: Re: [Gems-users] Invalidate directory entry


> Here are the relationships between the L1/L2 ports for
> MSI_MOSI_CMP_directory
>
> L1Cache                         L2Cache
> --------                        -------------
> out: requestFromL1Cache (0)     in: L1RequestToL2Cache (0)
> out: responseFromL1Cache (3)    in: responseToL2Cache (3)
> in:  requestToL1Cache (2)       out: L1RequestFromL2Cache (2)
> in:  responseToL1Cache (3)      out: responseFromL2Cache (3)
>
> Does this help?
>
> --Mike
>
>
> > So let's take protocol as an example, in the L2Cache.sm file:
> >
> > // L2 BANK QUEUES
> > // From local bank of L2 cache TO the network
> > MessageBuffer dummyFrom0, network="To", virtual_network="0", 
> > ordered="false";  // dummy buffer that shouldn't be used
> > MessageBuffer DirRequestFromL2Cache, network="To", virtual_network="1", 
> > ordered="false";  // this L2 bank -> mod-directory
> > >>>>>>>>>  MessageBuffer L1RequestFromL2Cache, network="To", 
> > >>>>>>>>> virtual_network="2", ordered="true";  // this L2 bank -> a 
> > >>>>>>>>> local L1
> > MessageBuffer responseFromL2Cache, network="To", virtual_network="3", 
> > ordered="false";  // this L2 bank -> a local L1 || mod-directory
> > MessageBuffer finalAckFromL2Cache, network="To", virtual_network="4", 
> > ordered="false";  // this L2 bank -> mod-directory
> > // FROM the network to this local bank of L2 cache
> > //MessageBuffer L1RequestToL2Cache, network="From", virtual_network="1", 
> > ordered="true";  // a local L1 -> this L2 bank
> > MessageBuffer L1RequestToL2Cache, network="From", virtual_network="0", 
> > ordered="true";  // a local L1 -> this L2 bank
> > MessageBuffer dummyTo1, network="From", virtual_network="1", 
> > ordered="false";  // dummy buffer that shouldn't be used
> > >>>>>>>>> MessageBuffer forwardedRequestToL2Cache, network="From", 
> > >>>>>>>>> virtual_network="2", ordered="true";  // mod-directory -> this 
> > >>>>>>>>> L2bank
> > MessageBuffer responseToL2Cache, network="From", virtual_network="3", 
> > ordered="false";  // a local L1 || mod-directory -> this L2 bank
> > MessageBuffer dummyTo4, network="From", virtual_network="4", 
> > ordered="false";  // dummy buffer that shouldn't be used
> > While in the L1Cache.sm file:
> >
> > // From this node's L1 cache TO the network
> > // a local L1 -> this L2 bank, currently ordered with directory forwarded 
> > requests
> > MessageBuffer requestFromL1Cache, network="To", virtual_network="0", 
> > ordered="true";
> > MessageBuffer dummyFrom1, network="To", virtual_network="1", 
> > ordered="false";  // dummy buffer that shouldn't be used
> > MessageBuffer dummyFrom2, network="To", virtual_network="2", 
> > ordered="false";  // dummy buffer that shouldn't be used
> > MessageBuffer responseFromL1Cache, network="To", virtual_network="3", 
> > ordered="false";
> > MessageBuffer dummyFrom4, network="To", virtual_network="4", 
> > ordered="false";  // dummy buffer that shouldn't be used
> > // To this node's L1 cache FROM the network
> > MessageBuffer dummyTo0, network="From", virtual_network="0", 
> > ordered="false";  // dummy buffer that shouldn't be used
> > MessageBuffer dummyTo1, network="From", virtual_network="1", 
> > ordered="false";  // dummy buffer that shouldn't be used
> > >>>>>>>>>>>  MessageBuffer requestToL1Cache, network="From", 
> > >>>>>>>>>>> virtual_network="2", ordered="true";
> > MessageBuffer responseToL1Cache, network="From", virtual_network="3", 
> > ordered="false";
> > MessageBuffer dummyTo4, network="From", virtual_network="4", 
> > ordered="false";  // dummy buffer that shouldn't be used
> >
> > So these three buffers should be connected together: 
> > L1RequestFromL2Cache, forwardedRequestToL2Cache, requestToL1Cache
> > because they have the same virtual network number, right? But this 
> > doesn't make sense to me, why should L1RequestFromL2Cache
> > be connected to forwardedRequestToL2Cache?
> >
> > Your advice is very much appreciated!
> >
> > Thanks,
> > Lei
> >   ----- Original Message -----
> >   From: hongxia sun
> >   To: Lei Yang ; Gems Users
> >   Sent: Thursday, January 11, 2007 8:45 PM
> >   Subject: Re: [Gems-users] Invalidate directory entry
> >
> >
> >   For the first question, you can modify the protocol as your design, 
> > both of the L2 cache and the directory.
> >   For the second question, these buffer are not connected according to 
> > their name, but according to their "virtual_network" No. Buffers with the 
> > same No. are connected together.
> >
> >   2007/1/12, Lei Yang <lya755@xxxxxxxxxxxxxxxxxxxx>:
> >     I see. So with this protocol (MSI_MOSI_CMP_directory), if Processor 0 
> > is the
> >     only sharer of one cache line, after it evicts this line, the 
> > directory
> >     state is still S. I've verified this with a simple trace. It doesn't 
> > matter
> >     with the current protocol because even if a line is shared by other 
> > L2
> >     caches, as long as it is not in M state, it's always fetched from 
> > main
> >     memory.  But for a protocol that supports clean cache-to-cache data
> >     transfer, this may be a problem.
> >
> >     Another question is, when reading the protocol sm files, I couldn't 
> > find
> >     where/how the buffers are connected. For example, there is a buffer 
> > for L2
> >     cache called L1RequestToL2Cache (a local L1 -> this L2 bank), but for 
> > L1
> >     cache, the buffer requestFromL1Cache is supposed to be Local L1 -> 
> > this L2
> >     bank. So with different names, how are they actually connected? I 
> > mean,
> >     after L1 sends a request to L2 using the requestFromL1Cache buffer, 
> > how does
> >     L2 actually receive it?
> >
> >     Thanks list, you've been super helpful!
> >
> >     Lei
> >
> >     ----- Original Message -----
> >     From: "Mike Marty" < mikem@xxxxxxxxxxx>
> >     To: "Lei Yang" <lya755@xxxxxxxxxxxxxxxxxxxx>
> >     Cc: "'Gems Users'" < gems-users@xxxxxxxxxxx>
> >     Sent: Thursday, January 11, 2007 9:41 AM
> >     Subject: Re: [Gems-users] Invalidate directory entry
> >
> >
> >     >> That's for M state, right? For S state, would any action be taken? 
> > Thanks
> >     >> a
> >     >> lot for your time!
> >     >>
> >     >
> >     > Yes, for S state the L2 silently replaces.
> >     >
> >     >
> >
> >
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