After being in the works for the past two years and going through 18+ rounds of code review, AMD ABMC looks poised to be mainlined for the upcoming Linux 6.18 kernel.
AMD ABMC is short for the Assignable Bandwidth Monitoring Counters. ABMC allows for full control over the L3 bandwidth monitoring resources in the QOS Domain. The “assignable” aspect is that system software can assign the bandwidth counters to a particular source RMID/COS for tracking the memory bandwidth of that particular source.
AMD ABMC took a lot of work to get into shape for the mainline kernel due to early objections around some design choices and making the implementation jive with ARM’s MPAM within the Linux kernel. The v18 patch series provides more detail onto ABMC and the Linux kernel usage of it with modern AMD EPYC server processors.
The news today is that the AMD ABMC patches have been queued into the x86/cache tip/tip.git branch. With the ABMC patches having finally reached a TIP branch, they’ll likely be submitted and merged for the upcoming Linux 6.18 kernel cycle to enable using this quality of service monitoring feature with recent AMD servers.
