Linux 7.4 scheduler cuts short-slice task latency up to 55%, adds NVIDIA Vera SMT preference
The Linux 7.4 kernel merges scheduler improvements including up to 55% lower latency for short-slice tasks and new SMT optimizations for NVIDIA's Vera CPUs.
Summary
Linaro engineer Vincent Guittot's EEVDF scheduler patches reduce short-slice task latency by up to 55% in Linux 7.4, building on similar work in 7.3. The merge also introduces a steal governor for dynamic vCPU management in virtual machines, NVIDIA Olympus core enhancements that prefer SMT siblings on Vera CPUs for 3-6% gains, and random idle CPU selection among equally-shallow cores for better performance on high core-count systems.
What's new in Linux 7.4 scheduling
- EEVDF scheduler update: Reduces scheduling latency for short-slice tasks by up to 55%, continuing work from Linux 7.3
- Steal governor: New dynamic vCPU management based on steal time to reduce preemption costs in Linux VMs
- NVIDIA Vera SMT preference: Olympus core enhancement prefers SMT siblings, showing 3-6% performance gains
- Random idle CPU selection: Picks randomly among equally-shallow idle CPU cores, targeting high core-count servers and workstations
- Cache scheduling fix: Prevents publishing partial last-level cache (LLC) utilization data
Why it matters
The latency improvements benefit real-time and interactive workloads on Linux desktops and servers, while the steal governor and SMT optimizations target cloud virtualization and NVIDIA's emerging Vera CPU platform respectively.
Original reference: www.phoronix.com →