MESI Two Level directory protocol: L1Cache - L2Cache - Directory - DMA - AccelL1Cache - AccelL2Cache - GPUCopyDMA - CrossingGuard

Fetch Data Memory Data Memory Ack DMA READ DMA WRITE CleanReplacement
I qf j / IM       qfd j / ID dw qwp j / ID W   I
ID z z dr q kd / I   zz zz   ID
ID W z z   da q kd / I zz zz   ID W
M inv z m qw k / MI     inv j / M DRD v inv j / M DWR a k kd / I M
IM z z d q kd / M   zz zz   IM
MI z z   aa q kd / I zz zz   MI
M DRD   drp m qw k / M DRDI     zz zz   M DRD
M DRDI z z   aa q kd / I zz zz   M DRDI
M DWR   m qwt k / M DWRI     zz zz   M DWR
M DWRI z z   dwt aa da w q kd / I zz zz   M DWRI
Fetch Data Memory Data Memory Ack DMA READ DMA WRITE CleanReplacement