Benchmarking Linux Kernel Memory Page Allocations (8094)

Technical Overview

Engineering breakdown of Benchmarking Linux Kernel Memory Page Allocations (8094). Bare-metal hardware performance requires isolated kernel parameters, NUMA-aware page placement, and precise measurement of allocation latency across order-0 to order-9 page requests. This article dissects the page allocator's fastpaths, the per-CPU page caches, the buddy allocator, and the impact of transparent huge pages (THP) on allocation throughput.

Methodology

• Kernel version: 6.8-rc3 with CONFIG_DEBUG_VM=y
• Workload: custom ftrace + perf benchmarks on isolated CPUs
• Metrics: allocation latency (ns), fragmentation index, THP promotion rate

Key Findings

Order-0 allocations exhibit sub-150ns latency on idle systems but degrade under memory pressure. Higher-order allocations (order-3+) show exponential latency growth due to buddy allocator scanning and compaction overhead. THP enables 2MB page allocations with 40% latency reduction for order-9 requests when khugepaged is active.