MX and vector world

 VMXDOTP: A RISC-V Vector ISA Extension for Efficient Microscaling (MX) Format Acceleration

Takeaways:

1. Microscaling (MX) data formats, based on block floating-point (BFP) representations, have emerged as a promising solution to reduce data volumes while preserving accuracy. However, MX semantics are poorly aligned with vector execution: block scaling and multi-step mixed-precision operations break the regularity of vector pipelines, leading to underutilized compute resources and performance degradation. 

2. As bitwidths decrease, preserving model accuracy becomes increasingly challenging due to the reduced dynamic range and precision [1]. To alleviate this trade-off, block-scaled data formats have emerged as a compelling solution. By associating a shared scale factor with a block of low-bitwidth elements, these formats preserve high dynamic range while retaining the benefits of a compact representation

3. While the memory savings of MX formats are a direct consequence of their compact design, their computational benefits are often overlooked. MX quantization is frequently treated as a storage-only compression approach to alleviate memory bottlenecks, requiring decompression to wider formats before computation [4], [5]