The resctrl MBA selftest is currently Intel-only: the test is vendor-gated to GenuineIntel and its reference bandwidth measurement is hard-wired to the Intel iMC uncore PMU. MPAM on arm64 exposes the same MB resource through resctrl, and NVIDIA Grace/Vera systems provide an uncore PMU (the SoC coherency fabric, SCF) that can serve as the same kind of independent reference that the iMC provides on x86.
Patches 1-2 decouple the test machinery from the iMC with no functional change and no NVIDIA code: a mechanical rename, then a small backend abstraction (detect()/setup_counters()) with the iMC as the only backend. Patch 3 teaches the framework the MPAM memory bandwidth monitoring layout (NUMA-node-keyed MB domains, MB_MON's mbm_total_bytes, ABMC counter assignment). Patch 4 switches the MBA test from vendor gating to feature detection. Patch 5 adds the NVIDIA SCF PMU as a reference bandwidth backend, making the MBA test runnable on arm64. The series builds after each patch, and mid-series behavior is sane: on arm64 the MBA test skips cleanly until patch 5, after which it runs and passes. x86 behavior is preserved throughout - the iMC stays the default backend and the mbm_local_bytes comparison path is unchanged. This series applies on top of the 26.04_linux-nvidia.glue.others.cpu_less.hardlimit branch of https://github.com/fyu1/NV-Kernels.fenghuay.baseos The base-commit recorded below is the current tip of that branch. Validated on a two-socket VR-NVL72 (Vera) system: the SCF-measured bandwidth and resctrl mbm_total_bytes agree within 3-4% across all MBA schemata levels (10%..100%), against the test's 8% threshold. Richard Cheng (5): selftests/resctrl: Make memory bandwidth measurement vendor-neutral selftests/resctrl: Abstract reference bandwidth counters behind a backend selftests/resctrl: Support the MPAM memory bandwidth monitoring layout selftests/resctrl: Gate the MBA test on features, not CPU vendor selftests/resctrl: Add NVIDIA SCF reference bandwidth backend tools/testing/selftests/resctrl/mba_test.c | 38 +- tools/testing/selftests/resctrl/mbm_test.c | 23 +- tools/testing/selftests/resctrl/resctrl.h | 6 +- tools/testing/selftests/resctrl/resctrl_val.c | 530 ++++++++++++++---- tools/testing/selftests/resctrl/resctrlfs.c | 45 +- 5 files changed, 519 insertions(+), 123 deletions(-) base-commit: 475f355d0408698d9f632ba3b9a5dfb1f91e928b -- 2.43.0
