AMD Engineer Details Zen 6 IBS Memory Profiler

"Linux currently finds those pages by scanning page tables and trapping page faults. AMD wants to feed the profiler's samples into pghot, a proposed kernel subsystem for hot page tracking. The results, however, are a mixed bag. On a test system with 256 logical CPUs and 256 GB of CXL memory, XSBench ran at 4.57x over a no-tiering baseline against 1.18x for the current method, and Graph500 hit 3.17x against 2.34x. Redis saw no gain, and NAS BT landed 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. These are AMD's own numbers, and the slides list no virtualization support for the profiler. The pghot patches are still in development, and EPYC Venice is in production with cloud deployments expected later this year."



Source: https://www.techpowerup.com/353525/amd-engineer-details-zen-6-ibs-memory-profiler

I just saw IBS and thought. wtf...