08-01-2013, 11:15 AM
Instruction-Level Parallel Processors
Instruction-Level.ppt (Size: 573.5 KB / Downloads: 96)
Improve CPU performance by
increasing clock rates
(CPU running at 2GHz!)
increasing the number of instructions to be executed in parallel
(executing 6 instructions at the same time)
Dependencies between instructions
Instructions often depend on each other in such a way that a particular instruction cannot be executed until a preceding instruction or even two or three preceding instructions have been executed.
1 Data dependencies
2 Control dependencies
3 Resource dependencies
Instruction scheduling
scheduling or arranging two or more instruction to be executed in parallel
Need to detect code dependency (detection)
Need to remove false dependency (resolution)
a means to extract parallelism
instruction-level parallelism which is implicit, is made explicit
Two basic approaches
Static: done by compiler
Dynamic: done by processor