I want to evaluate a private L2 CMP directory protocol in GEMS. Looking at some of the previous discussion it seems that lowering the network latencies and using an SMP protocol could mimic a private L2 CMP protocol.
My concern is that this would not model an on-chip directory cache. If I specify the directory link latency to be 200 cycles (to model off-chip memory), every check of the sharing vectors would incur an off-chip 200 cycle access.
You can add a directory cache to MOESI_SMP_directory-dir.sm. Just modify the actions to check for a directory cache hit and use a different latency value if you hit.
Am I correct? How have private L2 configurations been previously evaluated inside Gems?
Yes they have.
With private L2s, you can't really store directory state in the L2 tags.
--Mike
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