On Wed, Mar 10, 2021 at 11:02:33AM -0800, Alison Schofield wrote:
Commit 1340ccfa9a9a ("x86,sched: Allow topologies where NUMA nodes share an LLC") added a vendor and model specific check to never call topology_sane() for Intel Skylake Server systems where NUMA nodes share an LLC.
Intel Ice Lake and Sapphire Rapids CPUs also enumerate an LLC that is shared by multiple NUMA nodes. The LLC on these CPUs is shared for off-package data access but private to the NUMA node for on-package access. Rather than managing a list of allowable SNC topologies, make this SNC topology the default, and treat Intel's Cluster-On-Die (COD) topology as the exception.
In SNC mode, Sky Lake, Ice Lake, and Sapphire Rapids servers do not emit this warning:
sched: CPU #3's llc-sibling CPU #0 is not on the same node! [node: 1 != 0]. Ignoring dependency.
Acked-by: Dave Hansen dave.hansen@linux.intel.com Suggested-by: Peter Zijlstra (Intel) peterz@infradead.org Signed-off-by: Alison Schofield alison.schofield@intel.com
Seeing how this is basically what I gave you earlier; but now tested and with comments on,
Acked-by: Peter Zijlstra (Intel) peterz@infradead.org
Boris, will you make it happen, or you want me to queue it somewhere x86/core like?