Vectorizing for Fun and Performance
6 months ago
- #Performance Optimization
- #Vectorization
- #IBM Power
- IBM Power processors feature a vector processing facility (AltiVec, VMX, VSX) enabling SIMD operations.
- POWER8 has 64 vector-scalar registers (VSRs), each 128 bits, capable of holding multiple floating-point quantities.
- Vector instructions can perform operations like add, subtract, multiply, divide, and multiply-add simultaneously.
- Compilers support auto-vectorization but often require explicit implementation for optimal performance.
- Example provided: vectorized code for finding the maximum value in an array shows significant performance gains for larger arrays.
- Performance comparison: Non-vectorized vs. vectorized code shows a drastic reduction in execution time for 32 floats.