Sub-Numa Clustering (SNC) allows splitting CPU cores, caches and memory into multiple NUMA nodes. When enabled, NUMA-aware applications can achieve better performance on bigger server platforms. The series adding SNC support to the kernel is currently in review [1] but the selftests for resctrl need NUMA-aware adjustments to use these changes. Issues with resctrl selftests not working properly with SNC enabled were originally reported by Shaopeng Tan [2][3] and the following series resolves them. The main concept currently missing from resctrl selftests is that while resctrl tracks memory accesses on a single NUMA node (which normally is the same as the CPU socket) on machines with SNC enabled memory accesses can leak outside of the local NUMA node and into other NUMA nodes on the same socket. In that case resctrl could report a diminished value in one of its monitoring technologies: Cache Monitoring Technology (CMT) or Memory Bandwidth Monitoring (MBM) . Implemented solutions for both CMT and MBM follow the same idea which is to simply sum values reported by different NUMA nodes for a single Resource Monitoring ID (RMID). Series was tested on Ice Lake server platforms with SNC disabled, SNC-2 and SNC-4. The tests were also ran with and without kernel support for SNC. Series applies cleanly on kselftest/next. [1] https://lore.kernel.org/all/20240228112215.8044-tony.luck@xxxxxxxxx/ [2] https://lore.kernel.org/all/TYAPR01MB6330B9B17686EF426D2C3F308B25A@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/ [3] https://lore.kernel.org/lkml/TYAPR01MB6330A4EB3633B791939EA45E8B39A@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/ Maciej Wieczor-Retman (4): selftests/resctrl: Adjust effective L3 cache size with SNC enabled selftests/resctrl: SNC support for CMT selftests/resctrl: SNC support for MBM selftests/resctrl: Adjust SNC support messages tools/testing/selftests/resctrl/cache.c | 17 ++- tools/testing/selftests/resctrl/cat_test.c | 2 +- tools/testing/selftests/resctrl/cmt_test.c | 6 +- tools/testing/selftests/resctrl/mba_test.c | 3 +- tools/testing/selftests/resctrl/mbm_test.c | 4 +- tools/testing/selftests/resctrl/resctrl.h | 13 +- tools/testing/selftests/resctrl/resctrl_val.c | 46 ++++--- tools/testing/selftests/resctrl/resctrlfs.c | 128 +++++++++++++++++- 8 files changed, 185 insertions(+), 34 deletions(-) -- 2.44.0
