Why We Need SIMD
2 days ago
- #Performance Optimization
- #CPU Architecture
- #SIMD
- SIMD (Single Instruction, Multiple Data) delivers significant performance speedups at a modest area cost.
- SIMD instructions reuse existing CPU infrastructure like caches and decoding hardware, making them cost-effective.
- First SIMD on x86 was MMX, which performed 8 byte-sized operations per instruction, followed by wider SSE, AVX, and AVX512.
- SIMD requires software updates to utilize new instructions, unlike transparent CPU improvements like superscalarity.
- Video and cryptography benefit most from SIMD, but 3D rendering shifted to dedicated hardware, limiting SIMD's impact.
- AVX512, Intel's latest SIMD, includes advanced features like per-lane predication and mask registers for better performance.
- SIMD adoption is hindered by the need for developers to manually optimize code, unlike automatic hardware improvements.