Another Look At The Performance Impact To IBM's POWER9 L1d Flushing Change
On this larger POWER9 server backed by a Samsung 860 SATA 3.0 solid-state drive, the performance hit tended to be more noticeable than on the smaller POWER9 Blackbird test system.
In other I/O workloads as well there tended to be a measurable difference from this kernel change to beef up the POWER9 CPU security.