Kernel-Level Troubleshooting 101

Beyond User-Space: Mastering the Kernel Data Plane

Real-time platforms require predictable execution. Traditional "stock" kernels often introduce non-deterministic delays (jitter). This document covers the baseline configurations for low-latency kernel tuning.

CPU Isolation & Interrupt Affinity

Prevent the OS scheduler from interrupting critical processing threads.

• Isolcpus: Reserve specific CPU cores for the application logic only.
• IRQ Balance: Manually pin network card interrupts to specific cores to avoid "softirq" bottlenecks.

Memory Management: HugePages

Standard 4KB memory pages lead to high TLB (Translation Lookaside Buffer) miss rates under heavy loads.

• HugePages (2MB/1GB): Pre-allocate large memory blocks to reduce page table depth.
• Pre-faulting: Zero-fill and map all memory at startup to avoid "Major Page Faults" during execution.

Kernel Bypass Techniques

For ultra-high performance, bypass the networking stack entirely.

• DPDK/AF_XDP: Move the data plane to user-space for zero-copy packet processing.