A Macrotask-level Unlimited Speculative Execution on Multiprocessors
(16/19)
The following description is based on the paper presented at
1995 ACM International Conference on Supercomputing head
in Spain on July 3rd to 7th,1995.
If you want to have the copy of the paper, please
let me know.
Now, I'd like to address myself to the most important part. "Evaluation
of the distributed control scheme". The speedup in comparison with the
normal execution - I mean without speculation - is presented.
The target machine is the EM-4 Multiprocessor consisting of 80 PEs
whose clock cycle is 12.5MHz. In our implementation, the point to point
communication costs 3.3us. and Broadcast costs 26.4us.
This figure illustrates the implementation of the distributed control
on the EM-4. Four kinds of threads are programmed and running at every
processor.
- Broadcast controller sends the control signal to the two
neighbor processors for broadcasting.
- Status controller controls the execution of macrotasks.
- Scheduler allocates newly created macrotasks to the free processor.
- Macrotask is the macrotask itself.