Srikar Dronamraju <sri...@linux.vnet.ibm.com> writes: > If there are shared processor LPARs, underlying Hypervisor can have more > virtual cores to handle than actual physical cores. > > Starting with Power 9, a big core (aka SMT8 core) has 2 nearly > independent thread groups. On a shared processors LPARs, it helps to > pack threads to lesser number of cores so that the overall system > performance and utilization improves. PowerVM schedules at a big core > level. Hence packing to fewer cores helps. > > For example: Lets says there are two 8-core Shared LPARs that are > actually sharing a 8 Core shared physical pool, each running 8 threads > each. Then Consolidating 8 threads to 4 cores on each LPAR would help > them to perform better. This is because each of the LPAR will get > 100% time to run applications and there will no switching required by > the Hypervisor. >
Will this patch consolidate things to first 8 threads or just the one Big core? /me continues to look at other patches and wonder whether 4/5 should come before this? > > To achieve this, enable SD_ASYM_PACKING flag at CACHE, MC and DIE level > when the system is running in shared processor mode and has big cores. > > Signed-off-by: Srikar Dronamraju <sri...@linux.vnet.ibm.com> -aneesh