Hello! On 2024-05-30 at 16:07:34 -0700, Reinette Chatre wrote: >Hi Maciej, > >On 5/15/24 4:18 AM, Maciej Wieczor-Retman wrote: >> Resctrl selftest prints a message on test failure that Sub-Numa >> Clustering (SNC) could be enabled and points the user to check theirs BIOS >> settings. No actual check is performed before printing that message so >> it is not very accurate in pinpointing a problem. >> >> Figuring out if SNC is enabled is only one part of the problem, the >> other being whether the kernel supports it. As there is no easy >> interface that simply states SNC support in the kernel one can find that >> information by comparing L3 cache sizes from different sources. Cache >> size reported by /sys/devices/system/node/node0/cpu0/cache/index3/size >> will always show the full cache size even if it's split by enabled SNC. >> On the other hand /sys/fs/resctrl/size has information about L3 size, >> that with kernel support is adjusted for enabled SNC. >> >> Add a function to find a cache size from /sys/fs/resctrl/size since >> finding that information from the other source is already implemented. >> >> Add a function that compares the two cache sizes and use it to make the >> SNC support message more meaningful. > >Please note that the new version of SNC kernel support ([1]) that this >series is based on no longer adjusts the cache size. Detecting kernel support >for SNC (if the new solution is accepted) can be done with the test for the >existence of the files Tony mentioned in [2]. Thank you for your comments on both patches, I don't know how I missed this fact. I'll revise my patches accordingly. > >> >> Add the SNC support message just after MBA's check_results() since MBA >> shares code with MBM and also can suffer from enabled SNC if there is no >> support in the kernel. >> >> Signed-off-by: Maciej Wieczor-Retman <maciej.wieczor-retman@xxxxxxxxx> >> --- > >Reinette > >[1] https://lore.kernel.org/all/20240503203325.21512-1-tony.luck@xxxxxxxxx/ >[2] https://lore.kernel.org/lkml/SJ1PR11MB6083320F30DBCBB59574F0BDFCEC2@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/ > -- Kind regards Maciej Wieczór-Retman
