Fresh Linux 4.16 Kernel Benchmarks With KPTI & Retpolines

When focusing on PostgreSQL with just database reads, the performance hit since Linux 4.15 with KPTI/Retpolines is small.

But when introducing writes is where the hit is quite significant and even with disabling Retpolines and Kernel Page Table Isolations, the hit remains very dramatic.

Though if dealing with just one thread, as in a very lightly loaded database, the performance impact is obviously much less severe.

GIMP manipulation of image files is slightly slower with Linux 4.15 and 4.16 due to KPTI/Retpolines.