
7.8 Implications for Parallel Software 527
7.8.2 Shared Address Space Operations
It is useful to compare the communication architectures of the case study machines
for shared address space operations: read and write. These operations can easily be
built on top of the user-level message abstraction, but this does not exploit the oppor-
tunity to optimize for these simple, frequently occurring operations. In addition, on
machines where the assist does not provide enough interpretation, the remote proces-
sor is involved whenever its memory is accessed. In machines with a dedicated CP, it
can potentially service memory requests on behalf of remot ...