Key information
AMD engineer Bharata Bhasker Rao introduced a new IBS Memory Profiler for upcoming Zen 6 processors at the Linux Plumbers Conference 2026. This hardware feature specifically samples data memory accesses, providing the kernel with physical addresses and identifying whether data originated from DRAM or external sources like CXL.
The profiler aims to improve tiered-memory management in servers, particularly for EPYC 9006 Venice chips supporting CXL 3.1. By integrating these samples into the proposed pghot kernel subsystem, AMD intends to optimize the identification and migration of frequently accessed pages from slower CXL memory to faster DRAM.
Performance results shared by AMD show mixed outcomes. While XSBench and Graph500 demonstrated significant speedups compared to current page-table scanning methods, Redis showed no improvement, and NAS BT performed slightly worse. Additionally, an overhead test revealed a 5% slowdown despite reduced per-folio promotion costs.
The profiler currently lacks virtualization support according to the presentation slides. While the pghot patches remain under development, EPYC Venice chips are already in production, with cloud deployments anticipated later this year.
