Parallel Computer Architecture

5.3 Design Space for Snooping Protocols 291

FIGURE 5.12 Preserving the orders in a sequential

program running on a uniprocessor. Only the orders

corresponding to the two dependence arcs must be pre-

served.

The first two operations can be reordered

with-

out a problem, as can the last two or the middle two.

that seen by the programmer. On the hardware side, we assume that the sufficient

conditions must be satisfied. To do this, we need mechanisms for a processor to

detect completion of its writes so it may proceed past them (completion of reads is

easy; a read completes when the data returns to the processor) and mechanisms to

satisfy the conditio ...