A Look At The Relative Spectre/Meltdown Mitigation Costs On Windows vs. Linux

First up was the Golang benchmark where the patched Windows installation was running at 80% the speed of without the branch target injection mitigation and kernel VA shadow active. Ubuntu and Clear Linux meanwhile were still running at 90% of the speed without their KPTI and Retpoline code active.

With the BlogBench benchmark that aims to mimick the workload of a web server hosting a blog, both Clear Linux and Windows 10 were at 98% of their unpatched speed but Ubuntu was at 76%.

With the Git test profile that measures the time to carry out common Git commands on the GTK source repository, the performance impact was measurable but on all three operating systems just a few percent slower.

OSBench is one of the newest test profiles added this week to OpenBenchmarking.org as an operating system micro-benchmark. Unfortunately it wasn't working with Clear Linux but on Ubuntu and Windows 10 it shows clear cases of the impact of Spectre/Meltdown mitigation. The Windows vs. Linux impact varied from being about the same to Ubuntu having less of an impact on its daily Ubuntu 18.04 snapshot where KPTI and Retpoline are active.