Hi Maciej,
On 12/16/24 7:18 AM, Maciej Wieczor-Retman wrote:
Sub-NUMA Cluster divides CPUs sharing an L3 cache into separate NUMA nodes. Systems may support splitting into either two, three, four or six nodes. When SNC mode is enabled the effective amount of L3 cache available for allocation is divided by the number of nodes per L3.
It's possible to detect which SNC mode is active by comparing the number of CPUs that share a cache with CPU0, with the number of CPUs on node0.
Detect SNC mode once and let other tests inherit that information.
Update CFLAGS after including lib.mk in the Makefile so that fallthrough macro can be used.
To check if SNC detection is reliable one can check the /sys/devices/system/cpu/offline file. If it's empty, it means all cores are operational and the ratio should be calculated correctly. If it has any contents, it means the detected SNC mode can't be trusted and should be disabled.
Check if detection was not reliable due to offline cpus. If it was skip running tests since the results couldn't be trusted.
Co-developed-by: Tony Luck tony.luck@intel.com Signed-off-by: Tony Luck tony.luck@intel.com Signed-off-by: Maciej Wieczor-Retman maciej.wieczor-retman@intel.com
Thank you very much.
Reviewed-by: Reinette Chatre reinette.chatre@intel.com
Reinette