AMD outlines Zen 6 memory profiling feature

AMD has detailed the IBS Memory Profiler, a hardware feature planned for Zen 6 processors, during the Linux Plumbers Conference (LPC) 2026 in Prague on October 5. The feature builds on AMD’s existing Instruction-Based Sampling hardware by adding a separate, lighter instance focused only on data memory accesses. Each sample gives the kernel the physical address of the access and indicates whether the data came from DRAM or external memory such as CXL.

The capability is aimed at tiered-memory servers, where Linux needs to identify frequently used hot pages sitting on slower CXL memory and move them to DRAM. AMD’s EPYC 9006 Venice chips support memory expansion through CXL 3.1, and AMD wants the profiler’s samples to feed into pghot, a proposed Linux kernel subsystem for hot page tracking.

AMD’s benchmark results were uneven. On a test system with 256 logical CPUs and 256 GB of CXL memory, XSBench ran at 4.57x over a no-tiering baseline compared with 1.18x for the current method, while Graph500 reached 3.17x compared with 2.34x. Redis saw no gain, and NAS BT was slightly behind. Per-folio promotion cost fell from 26.1 to 15.8 microseconds in an overhead test, though that benchmark finished about 5% slower. The slides list no virtualization support, pghot patches remain in development, and EPYC Venice is in production with cloud deployments expected later this year.