Re: [Gems-users] Invalidate directory entry

["hongxia sun" <sunhx.seraph@xxxxxxxxx>]

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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