Speculation: Silicon’s Most Expensive Compulsion

Dr. Thang Tran, the Founder and CTO of Simplex Micro, discusses the significant silicon area and power dedicated to speculative execution in modern high-performance processors. He introduces Time-Based Scheduling (TBS) as an alternative architecture that eliminates the need for speculation by dispatching instructions when their data is ready. TBS focuses on vector processing units (VPUs) for AI workloads, where speculation can lead to wasted work across data elements. By removing speculation overhead, TBS allows for more efficient allocation of resources like execution units, cache capacity, and core count. The article highlights the drawbacks of speculation, the benefits of TBS, and the potential impact on various workload types.