Processors except the CPU

GPU

SPMD model implemented by a SIMD processor

SIMD vs SIMT

• SIMD: a single sequential instruction stream of SIMD instruction
• SIMT: Multiple instruction streams of scalar instructions

Grouping thread into warp --> advantage of SIMD
Independent execution of threads --> advantage of SPMD

VLIW

• simple hardware (no dynamic scheduling, dependency checking)

• compilation (complex and recompilation is needed for various thing, width, latency changes)
• lockstep execution causes independent operations to stall

DAE (Decoupled Access / Execute)

Motivation: Tomasulo's algorithm is too complex
Decouple Access (memory) / Execute (computing), communicate with queue

• Queues reduce registers
• OoO without wakeup/select complexity

• Branch synchronization between A and E
• multiple instruction streams?